Bump io.papermc.paperweight.userdev from 2.0.0-beta.21 to 2.0.0-beta.24 (#441)

* Some overall code health improvement
* Spigot BlockState handling optimization

.editorconfig

@@ -0,0 +1,491 @@
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 2
+indent_style = space
+insert_final_newline = false
+max_line_length = 120
+tab_width = 2
+ij_continuation_indent_size = 4
+ij_formatter_off_tag = @formatter:off
+ij_formatter_on_tag = @formatter:on
+ij_formatter_tags_enabled = true
+ij_smart_tabs = false
+ij_visual_guides = 
+ij_wrap_on_typing = false
+
+[*.java]
+ij_smart_tabs = true
+ij_java_align_consecutive_assignments = false
+ij_java_align_consecutive_variable_declarations = false
+ij_java_align_group_field_declarations = false
+ij_java_align_multiline_annotation_parameters = false
+ij_java_align_multiline_array_initializer_expression = false
+ij_java_align_multiline_assignment = false
+ij_java_align_multiline_binary_operation = false
+ij_java_align_multiline_chained_methods = false
+ij_java_align_multiline_deconstruction_list_components = true
+ij_java_align_multiline_extends_list = false
+ij_java_align_multiline_for = true
+ij_java_align_multiline_method_parentheses = false
+ij_java_align_multiline_parameters = false
+ij_java_align_multiline_parameters_in_calls = false
+ij_java_align_multiline_parenthesized_expression = false
+ij_java_align_multiline_records = true
+ij_java_align_multiline_resources = true
+ij_java_align_multiline_ternary_operation = false
+ij_java_align_multiline_text_blocks = false
+ij_java_align_multiline_throws_list = false
+ij_java_align_subsequent_simple_methods = false
+ij_java_align_throws_keyword = false
+ij_java_align_types_in_multi_catch = true
+ij_java_annotation_parameter_wrap = off
+ij_java_array_initializer_new_line_after_left_brace = false
+ij_java_array_initializer_right_brace_on_new_line = true
+ij_java_array_initializer_wrap = off
+ij_java_assert_statement_colon_on_next_line = false
+ij_java_assert_statement_wrap = off
+ij_java_assignment_wrap = off
+ij_java_binary_operation_sign_on_next_line = false
+ij_java_binary_operation_wrap = off
+ij_java_blank_lines_after_anonymous_class_header = 0
+ij_java_blank_lines_after_class_header = 0
+ij_java_blank_lines_after_imports = 1
+ij_java_blank_lines_after_package = 1
+ij_java_blank_lines_around_class = 1
+ij_java_blank_lines_around_field = 0
+ij_java_blank_lines_around_field_in_interface = 0
+ij_java_blank_lines_around_field_with_annotations = 0
+ij_java_blank_lines_around_initializer = 1
+ij_java_blank_lines_around_method = 1
+ij_java_blank_lines_around_method_in_interface = 1
+ij_java_blank_lines_before_class_end = 1
+ij_java_blank_lines_before_imports = 1
+ij_java_blank_lines_before_method_body = 0
+ij_java_blank_lines_before_package = 0
+ij_java_block_brace_style = end_of_line
+ij_java_block_comment_add_space = false
+ij_java_block_comment_at_first_column = true
+ij_java_builder_methods = 
+ij_java_call_parameters_new_line_after_left_paren = false
+ij_java_call_parameters_right_paren_on_new_line = true
+ij_java_call_parameters_wrap = off
+ij_java_case_statement_on_separate_line = true
+ij_java_catch_on_new_line = false
+ij_java_class_annotation_wrap = split_into_lines
+ij_java_class_brace_style = end_of_line
+ij_java_class_count_to_use_import_on_demand = 1000
+ij_java_class_names_in_javadoc = 1
+ij_java_deconstruction_list_wrap = normal
+ij_java_do_not_indent_top_level_class_members = false
+ij_java_do_not_wrap_after_single_annotation = false
+ij_java_do_not_wrap_after_single_annotation_in_parameter = false
+ij_java_do_while_brace_force = never
+ij_java_doc_add_blank_line_after_description = true
+ij_java_doc_add_blank_line_after_param_comments = false
+ij_java_doc_add_blank_line_after_return = false
+ij_java_doc_add_p_tag_on_empty_lines = true
+ij_java_doc_align_exception_comments = false
+ij_java_doc_align_param_comments = false
+ij_java_doc_do_not_wrap_if_one_line = false
+ij_java_doc_enable_formatting = true
+ij_java_doc_enable_leading_asterisks = true
+ij_java_doc_indent_on_continuation = false
+ij_java_doc_keep_empty_lines = true
+ij_java_doc_keep_empty_parameter_tag = true
+ij_java_doc_keep_empty_return_tag = true
+ij_java_doc_keep_empty_throws_tag = true
+ij_java_doc_keep_invalid_tags = true
+ij_java_doc_param_description_on_new_line = false
+ij_java_doc_preserve_line_breaks = false
+ij_java_doc_use_throws_not_exception_tag = true
+ij_java_else_on_new_line = false
+ij_java_enum_constants_wrap = off
+ij_java_enum_field_annotation_wrap = off
+ij_java_extends_keyword_wrap = off
+ij_java_extends_list_wrap = off
+ij_java_field_annotation_wrap = split_into_lines
+ij_java_field_name_prefix = 
+ij_java_field_name_suffix = 
+ij_java_finally_on_new_line = false
+ij_java_for_brace_force = never
+ij_java_for_statement_new_line_after_left_paren = false
+ij_java_for_statement_right_paren_on_new_line = true
+ij_java_for_statement_wrap = off
+ij_java_generate_final_locals = false
+ij_java_generate_final_parameters = false
+ij_java_generate_use_type_annotation_before_type = true
+ij_java_if_brace_force = never
+ij_java_imports_layout = @*,*,|,java.**,|,$*
+ij_java_indent_case_from_switch = true
+ij_java_insert_inner_class_imports = false
+ij_java_insert_override_annotation = true
+ij_java_keep_blank_lines_before_right_brace = 2
+ij_java_keep_blank_lines_between_package_declaration_and_header = 2
+ij_java_keep_blank_lines_in_code = 2
+ij_java_keep_blank_lines_in_declarations = 2
+ij_java_keep_builder_methods_indents = false
+ij_java_keep_control_statement_in_one_line = true
+ij_java_keep_first_column_comment = true
+ij_java_keep_indents_on_empty_lines = false
+ij_java_keep_line_breaks = true
+ij_java_keep_multiple_expressions_in_one_line = false
+ij_java_keep_simple_blocks_in_one_line = false
+ij_java_keep_simple_classes_in_one_line = true
+ij_java_keep_simple_lambdas_in_one_line = false
+ij_java_keep_simple_methods_in_one_line = false
+ij_java_label_indent_absolute = false
+ij_java_label_indent_size = 0
+ij_java_lambda_brace_style = end_of_line
+ij_java_layout_on_demand_import_from_same_package_first = true
+ij_java_layout_static_imports_separately = true
+ij_java_line_comment_add_space = false
+ij_java_line_comment_add_space_on_reformat = false
+ij_java_line_comment_at_first_column = true
+ij_java_local_variable_name_prefix = 
+ij_java_local_variable_name_suffix = 
+ij_java_method_annotation_wrap = split_into_lines
+ij_java_method_brace_style = end_of_line
+ij_java_method_call_chain_wrap = off
+ij_java_method_parameters_new_line_after_left_paren = true
+ij_java_method_parameters_right_paren_on_new_line = true
+ij_java_method_parameters_wrap = on_every_item
+ij_java_modifier_list_wrap = false
+ij_java_multi_catch_types_wrap = normal
+ij_java_names_count_to_use_import_on_demand = 10
+ij_java_new_line_after_lparen_in_annotation = false
+ij_java_new_line_after_lparen_in_deconstruction_pattern = true
+ij_java_new_line_after_lparen_in_record_header = false
+ij_java_new_line_when_body_is_presented = false
+ij_java_packages_to_use_import_on_demand = 
+ij_java_parameter_annotation_wrap = off
+ij_java_parameter_name_prefix = 
+ij_java_parameter_name_suffix = 
+ij_java_parentheses_expression_new_line_after_left_paren = false
+ij_java_parentheses_expression_right_paren_on_new_line = true
+ij_java_place_assignment_sign_on_next_line = false
+ij_java_prefer_longer_names = true
+ij_java_prefer_parameters_wrap = false
+ij_java_preserve_module_imports = true
+ij_java_record_components_wrap = normal
+ij_java_repeat_synchronized = true
+ij_java_replace_instanceof_and_cast = true
+ij_java_replace_null_check = true
+ij_java_replace_sum_lambda_with_method_ref = true
+ij_java_resource_list_new_line_after_left_paren = false
+ij_java_resource_list_right_paren_on_new_line = true
+ij_java_resource_list_wrap = off
+ij_java_rparen_on_new_line_in_annotation = true
+ij_java_rparen_on_new_line_in_deconstruction_pattern = true
+ij_java_rparen_on_new_line_in_record_header = true
+ij_java_space_after_closing_angle_bracket_in_type_argument = false
+ij_java_space_after_colon = true
+ij_java_space_after_comma = true
+ij_java_space_after_comma_in_type_arguments = true
+ij_java_space_after_for_semicolon = true
+ij_java_space_after_quest = true
+ij_java_space_after_type_cast = true
+ij_java_space_before_annotation_array_initializer_left_brace = false
+ij_java_space_before_annotation_parameter_list = false
+ij_java_space_before_array_initializer_left_brace = false
+ij_java_space_before_catch_keyword = true
+ij_java_space_before_catch_left_brace = true
+ij_java_space_before_catch_parentheses = true
+ij_java_space_before_class_left_brace = true
+ij_java_space_before_colon = true
+ij_java_space_before_colon_in_foreach = true
+ij_java_space_before_comma = false
+ij_java_space_before_deconstruction_list = false
+ij_java_space_before_do_left_brace = true
+ij_java_space_before_else_keyword = true
+ij_java_space_before_else_left_brace = true
+ij_java_space_before_finally_keyword = true
+ij_java_space_before_finally_left_brace = true
+ij_java_space_before_for_left_brace = true
+ij_java_space_before_for_parentheses = true
+ij_java_space_before_for_semicolon = false
+ij_java_space_before_if_left_brace = true
+ij_java_space_before_if_parentheses = true
+ij_java_space_before_method_call_parentheses = false
+ij_java_space_before_method_left_brace = true
+ij_java_space_before_method_parentheses = false
+ij_java_space_before_opening_angle_bracket_in_type_parameter = false
+ij_java_space_before_quest = true
+ij_java_space_before_switch_left_brace = true
+ij_java_space_before_switch_parentheses = true
+ij_java_space_before_synchronized_left_brace = true
+ij_java_space_before_synchronized_parentheses = true
+ij_java_space_before_try_left_brace = true
+ij_java_space_before_try_parentheses = true
+ij_java_space_before_type_parameter_list = false
+ij_java_space_before_while_keyword = true
+ij_java_space_before_while_left_brace = true
+ij_java_space_before_while_parentheses = true
+ij_java_space_inside_one_line_enum_braces = false
+ij_java_space_within_empty_array_initializer_braces = false
+ij_java_space_within_empty_method_call_parentheses = false
+ij_java_space_within_empty_method_parentheses = false
+ij_java_spaces_around_additive_operators = true
+ij_java_spaces_around_annotation_eq = true
+ij_java_spaces_around_assignment_operators = true
+ij_java_spaces_around_bitwise_operators = true
+ij_java_spaces_around_equality_operators = true
+ij_java_spaces_around_lambda_arrow = true
+ij_java_spaces_around_logical_operators = true
+ij_java_spaces_around_method_ref_dbl_colon = false
+ij_java_spaces_around_multiplicative_operators = true
+ij_java_spaces_around_relational_operators = true
+ij_java_spaces_around_shift_operators = true
+ij_java_spaces_around_type_bounds_in_type_parameters = true
+ij_java_spaces_around_unary_operator = false
+ij_java_spaces_inside_block_braces_when_body_is_present = false
+ij_java_spaces_within_angle_brackets = false
+ij_java_spaces_within_annotation_parentheses = false
+ij_java_spaces_within_array_initializer_braces = false
+ij_java_spaces_within_braces = false
+ij_java_spaces_within_brackets = false
+ij_java_spaces_within_cast_parentheses = false
+ij_java_spaces_within_catch_parentheses = false
+ij_java_spaces_within_deconstruction_list = false
+ij_java_spaces_within_for_parentheses = false
+ij_java_spaces_within_if_parentheses = false
+ij_java_spaces_within_method_call_parentheses = false
+ij_java_spaces_within_method_parentheses = false
+ij_java_spaces_within_parentheses = false
+ij_java_spaces_within_record_header = false
+ij_java_spaces_within_switch_parentheses = false
+ij_java_spaces_within_synchronized_parentheses = false
+ij_java_spaces_within_try_parentheses = false
+ij_java_spaces_within_while_parentheses = false
+ij_java_special_else_if_treatment = true
+ij_java_static_field_name_prefix = 
+ij_java_static_field_name_suffix = 
+ij_java_subclass_name_prefix = 
+ij_java_subclass_name_suffix = Impl
+ij_java_switch_expressions_wrap = normal
+ij_java_ternary_operation_signs_on_next_line = false
+ij_java_ternary_operation_wrap = off
+ij_java_test_name_prefix = 
+ij_java_test_name_suffix = Test
+ij_java_throws_keyword_wrap = off
+ij_java_throws_list_wrap = off
+ij_java_use_external_annotations = false
+ij_java_use_fq_class_names = false
+ij_java_use_relative_indents = false
+ij_java_use_single_class_imports = true
+ij_java_variable_annotation_wrap = off
+ij_java_visibility = public
+ij_java_while_brace_force = never
+ij_java_while_on_new_line = false
+ij_java_wrap_comments = false
+ij_java_wrap_first_method_in_call_chain = false
+ij_java_wrap_long_lines = false
+ij_java_wrap_semicolon_after_call_chain = false
+
+[*.properties]
+ij_properties_align_group_field_declarations = false
+ij_properties_keep_blank_lines = false
+ij_properties_key_value_delimiter = equals
+ij_properties_spaces_around_key_value_delimiter = false
+
+[.editorconfig]
+ij_editorconfig_align_group_field_declarations = false
+ij_editorconfig_space_after_colon = false
+ij_editorconfig_space_after_comma = true
+ij_editorconfig_space_before_colon = false
+ij_editorconfig_space_before_comma = false
+ij_editorconfig_spaces_around_assignment_operators = true
+
+[{*.ant,*.fxml,*.jhm,*.jnlp,*.jrxml,*.jspx,*.pom,*.rng,*.tagx,*.tld,*.wsdl,*.xml,*.xsd,*.xsl,*.xslt,*.xul}]
+ij_xml_align_attributes = true
+ij_xml_align_text = false
+ij_xml_attribute_wrap = normal
+ij_xml_block_comment_add_space = false
+ij_xml_block_comment_at_first_column = true
+ij_xml_keep_blank_lines = 2
+ij_xml_keep_indents_on_empty_lines = false
+ij_xml_keep_line_breaks = true
+ij_xml_keep_line_breaks_in_text = true
+ij_xml_keep_whitespaces = false
+ij_xml_keep_whitespaces_around_cdata = preserve
+ij_xml_keep_whitespaces_inside_cdata = false
+ij_xml_line_comment_at_first_column = true
+ij_xml_space_after_tag_name = false
+ij_xml_space_around_equals_in_attribute = false
+ij_xml_space_inside_empty_tag = false
+ij_xml_text_wrap = normal
+
+[{*.bash,*.sh,*.zsh}]
+ij_shell_binary_ops_start_line = false
+ij_shell_keep_column_alignment_padding = false
+ij_shell_minify_program = false
+ij_shell_redirect_followed_by_space = false
+ij_shell_switch_cases_indented = false
+ij_shell_use_unix_line_separator = true
+
+[{*.kt,*.kts}]
+ij_kotlin_align_in_columns_case_branch = false
+ij_kotlin_align_multiline_binary_operation = false
+ij_kotlin_align_multiline_extends_list = false
+ij_kotlin_align_multiline_method_parentheses = false
+ij_kotlin_align_multiline_parameters = true
+ij_kotlin_align_multiline_parameters_in_calls = false
+ij_kotlin_allow_trailing_comma = false
+ij_kotlin_allow_trailing_comma_on_call_site = false
+ij_kotlin_assignment_wrap = normal
+ij_kotlin_blank_lines_after_class_header = 0
+ij_kotlin_blank_lines_around_block_when_branches = 0
+ij_kotlin_blank_lines_before_declaration_with_comment_or_annotation_on_separate_line = 1
+ij_kotlin_block_comment_add_space = false
+ij_kotlin_block_comment_at_first_column = true
+ij_kotlin_call_parameters_new_line_after_left_paren = true
+ij_kotlin_call_parameters_right_paren_on_new_line = true
+ij_kotlin_call_parameters_wrap = on_every_item
+ij_kotlin_catch_on_new_line = false
+ij_kotlin_class_annotation_wrap = split_into_lines
+ij_kotlin_code_style_defaults = KOTLIN_OFFICIAL
+ij_kotlin_continuation_indent_for_chained_calls = false
+ij_kotlin_continuation_indent_for_expression_bodies = false
+ij_kotlin_continuation_indent_in_argument_lists = false
+ij_kotlin_continuation_indent_in_elvis = false
+ij_kotlin_continuation_indent_in_if_conditions = false
+ij_kotlin_continuation_indent_in_parameter_lists = false
+ij_kotlin_continuation_indent_in_supertype_lists = false
+ij_kotlin_else_on_new_line = false
+ij_kotlin_enum_constants_wrap = off
+ij_kotlin_extends_list_wrap = normal
+ij_kotlin_field_annotation_wrap = split_into_lines
+ij_kotlin_finally_on_new_line = false
+ij_kotlin_if_rparen_on_new_line = true
+ij_kotlin_import_nested_classes = false
+ij_kotlin_imports_layout = *,java.**,javax.**,kotlin.**,^
+ij_kotlin_indent_before_arrow_on_new_line = true
+ij_kotlin_insert_whitespaces_in_simple_one_line_method = true
+ij_kotlin_keep_blank_lines_before_right_brace = 2
+ij_kotlin_keep_blank_lines_in_code = 2
+ij_kotlin_keep_blank_lines_in_declarations = 2
+ij_kotlin_keep_first_column_comment = true
+ij_kotlin_keep_indents_on_empty_lines = false
+ij_kotlin_keep_line_breaks = true
+ij_kotlin_lbrace_on_next_line = false
+ij_kotlin_line_break_after_multiline_when_entry = true
+ij_kotlin_line_comment_add_space = false
+ij_kotlin_line_comment_add_space_on_reformat = false
+ij_kotlin_line_comment_at_first_column = true
+ij_kotlin_method_annotation_wrap = split_into_lines
+ij_kotlin_method_call_chain_wrap = normal
+ij_kotlin_method_parameters_new_line_after_left_paren = true
+ij_kotlin_method_parameters_right_paren_on_new_line = true
+ij_kotlin_method_parameters_wrap = on_every_item
+ij_kotlin_name_count_to_use_star_import = 5
+ij_kotlin_name_count_to_use_star_import_for_members = 3
+ij_kotlin_packages_to_use_import_on_demand = java.util.*,kotlinx.android.synthetic.**,io.ktor.**
+ij_kotlin_parameter_annotation_wrap = off
+ij_kotlin_space_after_comma = true
+ij_kotlin_space_after_extend_colon = true
+ij_kotlin_space_after_type_colon = true
+ij_kotlin_space_before_catch_parentheses = true
+ij_kotlin_space_before_comma = false
+ij_kotlin_space_before_extend_colon = true
+ij_kotlin_space_before_for_parentheses = true
+ij_kotlin_space_before_if_parentheses = true
+ij_kotlin_space_before_lambda_arrow = true
+ij_kotlin_space_before_type_colon = false
+ij_kotlin_space_before_when_parentheses = true
+ij_kotlin_space_before_while_parentheses = true
+ij_kotlin_spaces_around_additive_operators = true
+ij_kotlin_spaces_around_assignment_operators = true
+ij_kotlin_spaces_around_elvis = true
+ij_kotlin_spaces_around_equality_operators = true
+ij_kotlin_spaces_around_function_type_arrow = true
+ij_kotlin_spaces_around_logical_operators = true
+ij_kotlin_spaces_around_multiplicative_operators = true
+ij_kotlin_spaces_around_range = false
+ij_kotlin_spaces_around_relational_operators = true
+ij_kotlin_spaces_around_unary_operator = false
+ij_kotlin_spaces_around_when_arrow = true
+ij_kotlin_variable_annotation_wrap = off
+ij_kotlin_while_on_new_line = false
+ij_kotlin_wrap_elvis_expressions = 1
+ij_kotlin_wrap_expression_body_functions = 1
+ij_kotlin_wrap_first_method_in_call_chain = false
+
+[{*.har,*.json,*.jsonc,*.mcmeta,.prettierrc}]
+ij_json_array_wrapping = split_into_lines
+ij_json_keep_blank_lines_in_code = 0
+ij_json_keep_indents_on_empty_lines = false
+ij_json_keep_line_breaks = true
+ij_json_keep_trailing_comma = false
+ij_json_object_wrapping = split_into_lines
+ij_json_property_alignment = do_not_align
+ij_json_space_after_colon = true
+ij_json_space_after_comma = true
+ij_json_space_before_colon = false
+ij_json_space_before_comma = false
+ij_json_spaces_within_braces = false
+ij_json_spaces_within_brackets = false
+ij_json_wrap_long_lines = false
+
+[{*.htm,*.html,*.sht,*.shtm,*.shtml}]
+ij_html_add_new_line_before_tags = body,div,p,form,h1,h2,h3
+ij_html_align_attributes = true
+ij_html_align_text = false
+ij_html_attribute_wrap = normal
+ij_html_block_comment_add_space = false
+ij_html_block_comment_at_first_column = true
+ij_html_do_not_align_children_of_min_lines = 0
+ij_html_do_not_break_if_inline_tags = title,h1,h2,h3,h4,h5,h6,p
+ij_html_do_not_indent_children_of_tags = html,body,thead,tbody,tfoot
+ij_html_enforce_quotes = false
+ij_html_inline_tags = a,abbr,acronym,b,basefont,bdo,big,br,cite,cite,code,dfn,em,font,i,img,input,kbd,label,q,s,samp,select,small,span,strike,strong,sub,sup,textarea,tt,u,var
+ij_html_keep_blank_lines = 2
+ij_html_keep_indents_on_empty_lines = false
+ij_html_keep_line_breaks = true
+ij_html_keep_line_breaks_in_text = true
+ij_html_keep_whitespaces = false
+ij_html_keep_whitespaces_inside = span,pre,textarea
+ij_html_line_comment_at_first_column = true
+ij_html_new_line_after_last_attribute = never
+ij_html_new_line_before_first_attribute = never
+ij_html_quote_style = double
+ij_html_remove_new_line_before_tags = br
+ij_html_space_after_tag_name = false
+ij_html_space_around_equality_in_attribute = false
+ij_html_space_inside_empty_tag = false
+ij_html_text_wrap = normal
+
+[{*.markdown,*.md}]
+ij_markdown_force_one_space_after_blockquote_symbol = true
+ij_markdown_force_one_space_after_header_symbol = true
+ij_markdown_force_one_space_after_list_bullet = true
+ij_markdown_force_one_space_between_words = true
+ij_markdown_format_tables = true
+ij_markdown_insert_quote_arrows_on_wrap = true
+ij_markdown_keep_indents_on_empty_lines = false
+ij_markdown_keep_line_breaks_inside_text_blocks = true
+ij_markdown_max_lines_around_block_elements = 1
+ij_markdown_max_lines_around_header = 1
+ij_markdown_max_lines_between_paragraphs = 1
+ij_markdown_min_lines_around_block_elements = 1
+ij_markdown_min_lines_around_header = 1
+ij_markdown_min_lines_between_paragraphs = 1
+ij_markdown_wrap_text_if_long = true
+ij_markdown_wrap_text_inside_blockquotes = true
+
+[{*.toml,Cargo.lock,Cargo.toml.orig,Gopkg.lock,Pipfile,poetry.lock,uv.lock}]
+ij_toml_keep_indents_on_empty_lines = false
+
+[{*.yaml,*.yml}]
+ij_yaml_align_values_properties = do_not_align
+ij_yaml_autoinsert_sequence_marker = true
+ij_yaml_block_mapping_on_new_line = false
+ij_yaml_indent_sequence_value = true
+ij_yaml_keep_indents_on_empty_lines = false
+ij_yaml_keep_line_breaks = true
+ij_yaml_line_comment_add_space = false
+ij_yaml_line_comment_add_space_on_reformat = false
+ij_yaml_line_comment_at_first_column = true
+ij_yaml_sequence_on_new_line = false
+ij_yaml_space_before_colon = false
+ij_yaml_spaces_within_braces = true
+ij_yaml_spaces_within_brackets = true

.gitattributes

@@ -0,0 +1,11 @@
+# Use lf endings by default.
+* text=auto eol=lf
+
+# Declare text file types just in case
+*.java text
+*.yml text
+*.xml text
+*.md text
+
+# Exclude binary files
+*.png binary

.github/dependabot.yml

@@ -4,7 +4,16 @@ updates:
     directory: "/"
     schedule:
       interval: "monthly"
-  - package-ecosystem: "maven"
+  - package-ecosystem: "gradle"
     directory: "/"
     schedule:
       interval: "monthly"
+    ignore:
+      # The SQLite JDBC is provided by Spigot and, for now, Paper.
+      # To ensure it is still present even if Paper stops providing it,
+      # we need to declare it as a library.
+      # To prevent needlessly downloading (and loading) a second copy,
+      # we want to ensure that we are using the provided version.
+      - dependency-name: "org.xerial:sqlite-jdbc"
+      # Spigot and Spigot API updates are manual.
+      - dependency-name: "org.spigotmc:*"

.github/workflows/automerge_dependabot.yml

@@ -15,7 +15,7 @@ jobs:
       # Note: this is directly from GitHub's example for using data from a triggering workflow:
       # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#using-data-from-the-triggering-workflow
       - name: 'Download artifact'
-        uses: actions/github-script@v7
+        uses: actions/github-script@v9
         with:
           script: |
             let allArtifacts = await github.rest.actions.listWorkflowRunArtifacts({
@@ -47,7 +47,7 @@ jobs:
           github-token: "${{ secrets.GITHUB_TOKEN }}"
           pull-request-number: "${{ env.PR_NUMBER }}"
       - name: Merge
-        uses: pascalgn/automerge-action@v0.16.3
+        uses: pascalgn/automerge-action@v0.16.4
         env:
           GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
           MERGE_LABELS: "dependencies,java"

.github/workflows/ci.yml

@@ -3,9 +3,11 @@ name: OpenInv CI
 on:
   push:
     branches:
-      - '**'
+      - 'master'
     tags-ignore:
       - '**'
+    paths-ignore:
+      - resource-pack/openinv-legibility-pack/**
   # Enable running CI via other Actions, i.e. for drafting releases and handling PRs.
   workflow_call:
 
@@ -13,31 +15,22 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
-      - uses: actions/setup-java@v4
+      - uses: actions/setup-java@v6
         with:
           distribution: 'temurin'
-          java-version: '21'
-          cache: 'maven'
+          java-version: '25'
 
-      # Install Spigot dependencies if necessary.
-      - name: Install Spigot Dependencies
-        run: . scripts/install_spigot_dependencies.sh
+      - uses: gradle/actions/setup-gradle@v5
 
-      - name: Build With Maven
-        run: mvn -e clean package -am -P all
+      - name: Build with Gradle
+        run: ./gradlew build
 
       # Upload artifacts
       - name: Upload Distributable Jar
         id: upload-final
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: dist
-          path: ./target/OpenInv.jar
-      - name: Upload API Jar
-        id: upload-api
-        uses: actions/upload-artifact@v4
-        with:
-          name: api
-          path: ./api/target/openinvapi*.jar
+          path: ./dist/*

.github/workflows/draft_release.yml

@@ -12,28 +12,27 @@ jobs:
     needs: [ run-ci ]
     runs-on: ubuntu-latest
     steps:
-      # Fetch all history - used to assemble changelog.
-      - uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-
-      - name: Set Release Variables
-        run: bash ./scripts/set_release_env.sh
-
-      - name: Download Artifact
-        uses: actions/download-artifact@v4
+      - name: Download build
+        uses: actions/download-artifact@v8
         with:
           name: dist
           path: dist
 
       - name: Create Release
         id: create-release
-        uses: softprops/action-gh-release@v2.0.4
+        uses: softprops/action-gh-release@v3.0.3
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
-          name: ${{ env.VERSIONED_NAME }}
-          body: ${{ env.GENERATED_CHANGELOG }}
+          name: "OpenInv ${{ github.ref_name }}"
+          body: |-
+            ## Supported server versions
+            
+            **Paper:** TODO VERSION, 26.1.2, 1.21.11, 1.21.10, 1.21.9, 1.21.8, 1.21.7, 1.21.6  
+            **Spigot:** TODO VERSION
+            
+            TODO HELLO HUMAN, PRESS THE GENERATE CHANGELOG BUTTON PLEASE.
+            Don't forget to add a newline after the resulting header and prettify the tag compare link!
           draft: true
           prerelease: false
-          files: ./dist/OpenInv.jar
+          files: ./dist/**

.github/workflows/external_release.yml

@@ -1,4 +1,4 @@
-name: Release to CurseForge
+name: Release to external sites
 
 on:
   release:
@@ -8,30 +8,103 @@ jobs:
   curseforge_release:
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout Code
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
+      - &parse-paper-versions
+        name: Parse Paper Versions
+        id: parse_versions
+        run: |
+          # Find line declaring Paper versions.
+          raw=$(grep "\\*\\*Paper:\\*\\*" <<< "${{ github.event.release.body }}")
 
-      - name: Fetch Github Release Asset
+          # Enable extended glob pattern to match 0 or more whitespace characters.
+          shopt -s extglob
+          # Trim Paper versions identifier prefix.
+          raw=${raw/*([[:space:]])'**'Paper:'**'*([[:space:]])/}
+          # Replace commas and optional spaces with a newline.
+          raw=${raw//,*([[:space:]])/$'\n'}
+          # Turn extglob back off.
+          shopt -u extglob
+
+          echo "$raw"
+          printf "PAPER_VERSIONS<<EOF\n%s\nEOF\n" "$raw" >> "$GITHUB_OUTPUT"
+
+      - &fetch-release-asset
+        name: Fetch Github Release Asset
         uses: dsaltares/fetch-gh-release-asset@1.1.2
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           version: ${{ github.event.release.id }}
           file: OpenInv.jar
 
-      - name: Set CurseForge Variables
-        run: . scripts/set_curseforge_env.sh "${{ github.event.release.body }}"
-
       - name: Create CurseForge Release
-        uses: itsmeow/curseforge-upload@v3
+        uses: Kira-NT/mc-publish@v3.3
         with:
-          token: "${{ secrets.CURSEFORGE_TOKEN }}"
-          project_id: 31432
-          game_endpoint: minecraft
-          file_path: ./OpenInv.jar
-          display_name: "${{ github.event.release.name }}"
-          game_versions: "${{ env.CURSEFORGE_MINECRAFT_VERSIONS }}"
-          release_type: release
-          changelog_type: markdown
-          changelog: "${{ env.CURSEFORGE_CHANGELOG }}"
+          curseforge-token: ${{ secrets.CURSEFORGE_TOKEN }}
+          curseforge-id: 31432
+          files: ./OpenInv.jar
+          game-versions: "${{ steps.parse_versions.outputs.PAPER_VERSIONS }}"
+          game-version-filter: releases
+          loaders: |
+            spigot
+            paper
+            folia
+
+  modrinth_release:
+    runs-on: ubuntu-latest
+    steps:
+      - *parse-paper-versions
+      - *fetch-release-asset
+
+      - name: Create Modrinth Release
+        uses: Kira-NT/mc-publish@v3.3
+        with:
+          modrinth-id: 1UlvXbzL
+          modrinth-featured: false
+          modrinth-unfeature-mode: none
+          modrinth-token: ${{ secrets.MODRINTH_TOKEN }}
+          files: ./OpenInv.jar
+          game-versions: "${{ steps.parse_versions.outputs.PAPER_VERSIONS }}"
+          game-version-filter: releases
+          loaders: |
+            spigot
+            paper
+            folia
+
+  hangar_release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Parse Hangar Paper Versions
+        id: parse_versions
+        run: |
+          # Find line declaring Paper versions.
+          raw=$(grep "\\*\\*Paper:\\*\\*" <<< "${{ github.event.release.body }}")
+          # Trim Paper versions identifier prefix.
+          raw="${raw/'**'Paper:'**'/}"
+          # Trim leading and trailing spaces.
+          raw="${raw##[[:space:]]}"
+          raw="${raw%%[[:space:]]}"
+
+          # Generate JSON for Hangar. GitHub Actions provides jq 1.7 in the 24.04 image.
+          # Split on comma and optional spaces.
+          hangar_versions=$(jq -nc --arg versions "$raw" '{"PAPER": $versions | split(", *";null)}')
+
+          echo "$hangar_versions"
+          echo "HANGAR_PAPER_VERSIONS=$hangar_versions" >> "$GITHUB_OUTPUT"
+
+      - *fetch-release-asset
+
+      - name: Create Hangar Release
+        uses: benwoo1110/hangar-upload-action@v1
+        with:
+          api_token: ${{ secrets.HANGAR_TOKEN }}
+          slug: 'OpenInv'
+          version: ${{ github.event.release.tag_name }}
+          channel: release
+          description: "${{ github.event.release.body }}"
+          files: |-
+            [
+              {
+                "path": "./OpenInv.jar",
+                "platforms": ["PAPER"]
+              }
+            ]
+          platform_dependencies: "${{ steps.parse_versions.outputs.HANGAR_PAPER_VERSIONS }}"

.github/workflows/pull_request.yml

@@ -16,7 +16,7 @@ jobs:
         run: |
           mkdir -p ./pr
           echo ${{ github.event.number }} > ./pr/pr_number
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v7
         with:
           name: pr_number
           path: pr/

.github/workflows/resource_pack_ci.yml

@@ -0,0 +1,24 @@
+name: Resource Pack CI
+
+on:
+  push:
+    branches:
+      - 'master'
+    tags-ignore:
+      - '**'
+    paths:
+      - resource-pack/openinv-legibility-pack/**
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Build resource pack
+        id: upload-resource-pack
+        uses: actions/upload-artifact@v7
+        with:
+          name: openinv-legibility-pack
+          path: ./resource-pack/openinv-legibility-pack/
+          compression-level: 9

.gitignore

@@ -2,9 +2,13 @@
 **/.project
 **/.classpath
 **/.idea/
+**/.gradle/
 **.iml
 **/target/
 **/bin/
 **/out/
+**/build/
+**/dist/
 **/dependency-reduced-pom.xml
 **/pom.xml.versionsBackup
+**/.vscode/

README.MD

@@ -1,139 +0,0 @@
-## About
-OpenInv is a [Bukkit plugin](https://dev.bukkit.org/bukkit-plugins/openinv/) which allows users to open and edit anyone's inventory or ender chest - online or not!
-
-## Features
-- **OpenInv**: Open anyone's inventory, even if they're offline.
-  - Read-only mode! No edits allowed! Don't grant the permission `OpenInv.editinv`
-  - Cross-world support! Don't grant `OpenInv.crossworld`
-  - No self-opening! Don't grant `OpenInv.openself`
-  - Drop items as the player! Place items in the unused slots to the right of the armor to drop them
-- **OpenEnder**: Open anyone's ender chest, even if they're offline.
-  - Read-only mode! No edits allowed! Don't grant `OpenInv.editender`
-  - Cross-world support! Don't grant `OpenInv.crossworld`
-  - No opening others! Don't grant `OpenInv.openenderall`
-- **SilentContainer**: Open containers without displaying an animation or making sound.
-- **AnyContainer**: Open containers, even if blocked by ocelots or blocks.
-
-## Commands
-See [the wiki](https://github.com/Jikoo/OpenInv/wiki/Commands).
-
-## Permissions
-<table>
-  <tr>
-    <th>Node</th>
-    <th>Description</th>
-  </tr>
-  <tr>
-    <td>OpenInv.*</td>
-    <td>Gives permission to use all of OpenInv.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.openinv</td>
-    <td>Required to use /openinv.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.openself</td>
-    <td>Required to open own inventory.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.editinv</td>
-    <td>Required to make changes to open inventories.</td>
-  </tr>
-  <tr>
-      <td>OpenInv.openonline</td>
-      <td>Allows users to open online players' inventories. For compatibility reasons this is granted by the nodes OpenInv.openinv and OpenInv.openender.</td>
-  </tr>
-  <tr>
-      <td>OpenInv.openoffline</td>
-      <td>Allows users to open offline players' inventories. For compatibility reasons this is granted by the nodes OpenInv.openinv and OpenInv.openender.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.openender</td>
-    <td>Required to use /openender.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.editender</td>
-    <td>Required to make changes to open ender chests.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.openenderall</td>
-    <td>Allows users to open others' ender chests. Without it, users can only open their own.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.exempt</td>
-    <td>Prevents the player's inventory being opened by others.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.override</td>
-    <td>Allows bypassing of the exempt permission.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.crossworld</td>
-    <td>Allows cross-world usage of /openinv and /openender.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.search</td>
-    <td>Required to use /searchinv and /searchender.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.searchenchant</td>
-    <td>Required to use /searchenchant.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.anychest</td>
-    <td>Required to use /anychest.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.any.default</td>
-    <td>Cause AnyContainer to be enabled by default.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.silent</td>
-    <td>Required to use /silentcontainer.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.silent.default</td>
-    <td>Cause SilentContainer to be enabled by default.</td>
-  </tr>
-  <tr>
-    <td>OpenInv.spectate</td>
-    <td>Allows users in spectate gamemode to edit inventories.</td>
-  </tr>
-</table>
-
-## For Developers
-
-### As a Dependency
-The OpenInv API is available via [JitPack](https://jitpack.io/).
-```xml
-  <repositories>
-    <repository>
-      <id>jitpack.io</id>
-      <url>https://jitpack.io</url>
-    </repository>
-  </repositories>
-```
-```xml
-  <dependencies>
-    <dependency>
-      <groupId>com.github.jikoo.OpenInv</groupId>
-      <artifactId>openinvapi</artifactId>
-      <version>${openinv.version}</version>
-    </dependency>
-  </dependencies>
-```
-
-### Compilation
-To compile, the relevant Spigot jars must be installed in the local repository.
-As OpenInv is compiled against Mojang's mappings, you must run BuildTools with the `--remapped` argument:  
-`java -jar BuildTools.jar --remapped --rev $serverVersion`  
-`$serverVersion` is the version of the server, i.e. `1.18.1`
-
-To compile for a single version, specify the module you are targeting:  
-`mvn -pl $moduleName -am clean install`  
-`$moduleName` is the name of the module, i.e. `internal/v1_18_R1`.
-
-To compile for a set of versions, use a profile. Select a profile using the `-P` argument:  
-`mvn clean package -am -P all`  
-The only provided profile is `all`. The final file is `target/OpenInv.jar`  
-For more information, check out the [official Maven guide](http://maven.apache.org/guides/introduction/introduction-to-profiles.html).

README.md

@@ -0,0 +1,65 @@
+## About
+
+OpenInv is a Bukkit plugin which allows users to open and edit anyone's
+inventory or ender chest - online or not!
+
+Downloads are available on [GitHub](https://github.com/Jikoo/OpenInv/releases), [DBO](https://dev.bukkit.org/projects/openinv)/[CurseForge](https://www.curseforge.com/minecraft/bukkit-plugins/openinv), [Modrinth](https://modrinth.com/plugin/openinv), and [Hangar](https://hangar.papermc.io/jikoo/OpenInv).
+
+## Features
+
+- **OpenInv**: Open anyone's inventory, even if they're offline.
+  - Read-only mode! Don't grant edit permission.
+  - Cross-world support! Allow access only from the same world.
+  - No duplicate slots! Only armor is accessible when opening self (if allowed at all)!
+  - Drop items as the player! Place items in the dropper slot in the bottom right. Can be disabled via permission!
+  - Allow any item in armor slots! Configurable via permission.
+- **OpenEnder**: Open anyone's ender chest, even if they're offline.
+  - Allow access only to own ender chest! Don't grant permission to open others.
+  - Read-only mode! Don't grant edit permission.
+  - Cross-world support! Allow access only from the same world.
+- **SilentContainer**: Open containers without displaying an animation or making sound.
+- **AnyContainer**: Open containers, even if blocked by ocelots or blocks.
+- **Resource Pack Support**: Personalize view using resource pack tricks like custom fonts and characters. See [the wiki](https://github.com/Jikoo/OpenInv/wiki/Customizing-Inventories) for details.
+
+## Commands
+
+See [the wiki](https://github.com/Jikoo/OpenInv/wiki/Commands).
+
+## Permissions
+
+See [the wiki](https://github.com/Jikoo/OpenInv/wiki/Permissions)
+
+## For Developers
+
+### As a Dependency
+
+The OpenInv API is available via [JitPack](https://jitpack.io/).
+
+```xml
+  <repositories>
+    <repository>
+      <id>jitpack.io</id>
+      <url>https://jitpack.io</url>
+    </repository>
+  </repositories>
+```
+
+```xml
+  <dependencies>
+    <dependency>
+      <groupId>com.github.Jikoo</groupId>
+      <artifactId>OpenInv</artifactId>
+      <version>${openinv.version}</version>
+    </dependency>
+  </dependencies>
+```
+
+Note that since JitPack only builds the API now, the "full" OpenInv jar on JitPack is actually the openinvapi artifact.
+This is a change from previous dependency declaration that I hope to revert.
+
+### Compilation
+
+Execute the gradle wrapper:  
+`./gradlew build`
+
+If you encounter issues with building the Spigot module, try running BuildTools manually.

addon/togglepersist/build.gradle.kts

@@ -0,0 +1,31 @@
+repositories {
+  mavenCentral()
+  maven("https://hub.spigotmc.org/nexus/content/groups/public/")
+}
+
+dependencies {
+  compileOnly(libs.spigotapi)
+  implementation(project(":openinvapi"))
+}
+
+java {
+  toolchain.languageVersion = JavaLanguageVersion.of(21)
+}
+
+tasks.withType<JavaCompile>().configureEach {
+  options.release = 21
+}
+
+tasks.processResources {
+  expand("version" to version)
+}
+
+tasks.register<Copy>("distributeAddons") {
+  into(rootProject.layout.projectDirectory.dir("dist"))
+  from(tasks.jar)
+  rename("openinvtogglepersist.*\\.jar", "OITogglePersist.jar")
+}
+
+tasks.assemble {
+  dependsOn(tasks.named("distributeAddons"))
+}

addon/togglepersist/src/main/java/com/github/jikoo/openinv/togglepersist/TogglePersist.java

@@ -0,0 +1,152 @@
+package com.github.jikoo.openinv.togglepersist;
+
+import com.google.errorprone.annotations.Keep;
+import com.lishid.openinv.event.PlayerToggledEvent;
+import com.lishid.openinv.util.setting.PlayerToggle;
+import com.lishid.openinv.util.setting.PlayerToggles;
+import org.bukkit.configuration.Configuration;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import java.util.logging.Level;
+
+public class TogglePersist extends JavaPlugin implements Listener {
+
+  private final Map<UUID, Set<String>> enabledToggles = new HashMap<>();
+
+  @Override
+  public void onEnable() {
+    getServer().getPluginManager().registerEvents(this, this);
+
+    File file = new File(getDataFolder(), "toggles.yml");
+
+    // If there's no save file, there's nothing to load.
+    if (!file.exists()) {
+      return;
+    }
+
+    Configuration loaded = YamlConfiguration.loadConfiguration(file);
+
+    // For each toggle, enable loaded players.
+    for (String toggleName : loaded.getKeys(false)) {
+      PlayerToggle toggle = PlayerToggles.get(toggleName);
+      // Ensure toggle exists.
+      if (toggle == null) {
+        continue;
+      }
+
+      for (String idString : loaded.getStringList(toggleName)) {
+        // Ensure valid UUID.
+        UUID uuid;
+        try {
+          uuid = UUID.fromString(idString);
+        } catch (IllegalArgumentException e) {
+          continue;
+        }
+
+        // Track that toggle is enabled.
+        set(uuid, toggleName);
+      }
+    }
+  }
+
+  private void set(UUID playerId, String toggleName) {
+    enabledToggles.compute(
+        playerId,
+        (uuid, toggles) -> {
+          if (toggles == null) {
+            toggles = new HashSet<>();
+          }
+          toggles.add(toggleName);
+          return toggles;
+        }
+    );
+  }
+
+  @Override
+  public void onDisable() {
+    Map<String, List<String>> converted = getSaveData();
+
+    YamlConfiguration data = new YamlConfiguration();
+    for (Map.Entry<String, List<String>> playerToggle : converted.entrySet()) {
+      data.set(playerToggle.getKey(), playerToggle.getValue());
+    }
+
+    File file = new File(getDataFolder(), "toggles.yml");
+    try {
+      data.save(file);
+    } catch (IOException e) {
+      getLogger().log(Level.SEVERE, "Unable to save player toggle states", e);
+    }
+  }
+
+  private @NotNull Map<String, List<String>> getSaveData() {
+    Map<String, List<String>> converted = new HashMap<>();
+
+    for (Map.Entry<UUID, Set<String>> playerToggles : enabledToggles.entrySet()) {
+      String idString = playerToggles.getKey().toString();
+      for (String toggleName : playerToggles.getValue()) {
+        // Add player ID to listing for each enabled toggle.
+        converted.compute(
+            toggleName,
+            (name, ids) -> {
+              if (ids == null) {
+                ids = new ArrayList<>();
+              }
+              ids.add(idString);
+              return ids;
+            }
+        );
+      }
+    }
+    return converted;
+  }
+
+  @Keep
+  @EventHandler
+  private void onPlayerJoin(@NotNull PlayerJoinEvent event) {
+    UUID playerId = event.getPlayer().getUniqueId();
+    Set<String> toggleNames = enabledToggles.get(playerId);
+
+    if (toggleNames == null) {
+      return;
+    }
+
+    for (String toggleName : toggleNames) {
+      PlayerToggle toggle = PlayerToggles.get(toggleName);
+      if (toggle != null) {
+        toggle.set(playerId, true);
+      }
+    }
+  }
+
+  @Keep
+  @EventHandler
+  private void onToggleSet(@NotNull PlayerToggledEvent event) {
+    if (event.isEnabled()) {
+      set(event.getPlayerId(), event.getToggle().getName());
+    } else {
+      enabledToggles.computeIfPresent(
+          event.getPlayerId(),
+          (uuid, toggles) -> {
+            toggles.remove(event.getToggle().getName());
+            return toggles.isEmpty() ? null : toggles;
+          }
+      );
+    }
+  }
+
+}

addon/togglepersist/src/main/resources/plugin.yml

@@ -0,0 +1,7 @@
+name: OITogglePersist
+main: com.github.jikoo.openinv.togglepersist.TogglePersist
+version: ${version}
+author: Jikoo
+description: An OpenInv addon allowing /anycontainer and /silentcontainer to persist across sessions.
+api-version: "1.20"
+depend: [ OpenInv ]

api/build.gradle.kts

@@ -0,0 +1,30 @@
+plugins {
+  `maven-publish`
+}
+
+repositories {
+  mavenCentral()
+  maven("https://hub.spigotmc.org/nexus/content/groups/public/")
+}
+
+dependencies {
+  compileOnly(libs.spigotapi)
+}
+
+java {
+  toolchain.languageVersion = JavaLanguageVersion.of(21)
+}
+
+tasks.withType<JavaCompile>().configureEach {
+  options.release = 21
+}
+
+publishing {
+  publications {
+    create<MavenPublication>("jitpack") {
+      groupId = "com.github.Jikoo.OpenInv"
+      artifactId = "openinvapi"
+      from(components["java"])
+    }
+  }
+}

api/pom.xml

@@ -1,49 +0,0 @@
-<!--
-  ~ Copyright (C) 2011-2022 lishid. All rights reserved.
-  ~
-  ~ This program is free software: you can redistribute it and/or modify
-  ~ it under the terms of the GNU General Public License as published by
-  ~ the Free Software Foundation, version 3.
-  ~
-  ~ This program is distributed in the hope that it will be useful,
-  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
-  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-  ~ GNU General Public License for more details.
-  ~
-  ~ You should have received a copy of the GNU General Public License
-  ~ along with this program. If not, see <http://www.gnu.org/licenses/>.
-  -->
-
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-  <modelVersion>4.0.0</modelVersion>
-
-  <parent>
-    <artifactId>openinvparent</artifactId>
-    <groupId>com.lishid</groupId>
-    <version>4.4.4</version>
-  </parent>
-
-  <artifactId>openinvapi</artifactId>
-  <name>OpenInvAPI</name>
-
-  <dependencies>
-    <dependency>
-      <artifactId>annotations</artifactId>
-      <groupId>org.jetbrains</groupId>
-    </dependency>
-    <dependency>
-      <artifactId>spigot-api</artifactId>
-      <groupId>org.spigotmc</groupId>
-    </dependency>
-  </dependencies>
-
-  <build>
-    <plugins>
-      <plugin>
-        <artifactId>maven-compiler-plugin</artifactId>
-      </plugin>
-    </plugins>
-  </build>
-
-</project>

api/src/main/java/com/lishid/openinv/IOpenInv.java

@@ -17,274 +17,183 @@
 package com.lishid.openinv;
 
 import com.lishid.openinv.internal.IAnySilentContainer;
-import com.lishid.openinv.internal.IInventoryAccess;
 import com.lishid.openinv.internal.ISpecialEnderChest;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import com.lishid.openinv.util.InventoryAccess;
-import java.util.UUID;
-import java.util.logging.Logger;
 import org.bukkit.Bukkit;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryView;
-import org.bukkit.plugin.Plugin;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.util.UUID;
+import java.util.logging.Logger;
 
 /**
  * Interface defining behavior for the OpenInv plugin.
  */
+@NullMarked
 public interface IOpenInv {
 
-    /**
-     * Check if the server version is supported by OpenInv.
-     *
-     * @return true if the server version is supported
-     */
-    boolean isSupportedVersion();
+  /**
+   * Check if the server version is supported by OpenInv.
+   *
+   * @return true if the server version is supported
+   */
+  boolean isSupportedVersion();
 
-    /**
-     * Check the configuration value for whether OpenInv saves player data when unloading players. This is exclusively
-     * for users who do not allow editing of inventories, only viewing, and wish to prevent any possibility of bugs such
-     * as lishid#40. If true, OpenInv will not ever save any edits made to players.
-     *
-     * @return false unless configured otherwise
-     */
-    boolean disableSaving();
+  /**
+   * Check the configuration value for whether OpenInv saves player data when unloading players. This is exclusively
+   * for users who do not allow editing of inventories, only viewing, and wish to prevent any possibility of bugs such
+   * as lishid#40. If true, OpenInv will not ever save any edits made to players.
+   *
+   * @return false unless configured otherwise
+   */
+  boolean disableSaving();
 
-    /**
-     * Check the configuration value for whether OpenInv allows offline access. If true, OpenInv will not load or allow
-     * modification of players while they are not online. This does not prevent other plugins from using existing loaded
-     * players who have gone offline.
-     *
-     * @return false unless configured otherwise
-     * @since 4.2.0
-     */
-    boolean disableOfflineAccess();
+  /**
+   * Check the configuration value for whether OpenInv allows offline access. If true, OpenInv will not load or allow
+   * modification of players while they are not online. This does not prevent other plugins from using existing loaded
+   * players who have gone offline.
+   *
+   * @return false unless configured otherwise
+   * @since 4.2.0
+   */
+  boolean disableOfflineAccess();
 
-    /**
-     * Check the configuration value for whether OpenInv uses history for opening commands. If false, OpenInv will use
-     * the previous parameterized search when no parameters are provided.
-     *
-     * @return false unless configured otherwise
-     * @since 4.3.0
-     */
-    boolean noArgsOpensSelf();
+  /**
+   * Check the configuration value for whether OpenInv uses history for opening commands. If false, OpenInv will use
+   * the previous parameterized search when no parameters are provided.
+   *
+   * @return false unless configured otherwise
+   * @since 4.3.0
+   */
+  boolean noArgsOpensSelf();
 
-    /**
-     * Get the active {@link IAnySilentContainer} implementation.
-     *
-     * @return the active implementation for the server version
-     * @throws IllegalStateException if the server version is unsupported
-     */
-    @NotNull IAnySilentContainer getAnySilentContainer();
+  /**
+   * Get the active {@link IAnySilentContainer} implementation.
+   *
+   * @return the active implementation for the server version
+   * @throws IllegalStateException if the server version is unsupported
+   */
+  IAnySilentContainer getAnySilentContainer();
 
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default @NotNull IInventoryAccess getInventoryAccess() {
-        return new InventoryAccess();
-    }
+  /**
+   * Get whether a user has AnyContainer mode enabled.
+   *
+   * @param offline the user to obtain the state of
+   * @return true if AnyContainer mode is enabled
+   */
+  boolean getAnyContainerStatus(OfflinePlayer offline);
 
-    /**
-     * @deprecated Use {@link #getAnyContainerStatus(OfflinePlayer)}. Not all containers are chests.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default boolean getPlayerAnyChestStatus(@NotNull OfflinePlayer offline) {
-        return getAnyContainerStatus(offline);
-    }
+  /**
+   * Set whether a user has AnyContainer mode enabled.
+   *
+   * @param offline the user to set the state of
+   * @param status the state of the mode
+   */
+  void setAnyContainerStatus(OfflinePlayer offline, boolean status);
 
-    /**
-     * Get whether a user has AnyContainer mode enabled.
-     *
-     * @param offline the user to obtain the state of
-     * @return true if AnyContainer mode is enabled
-     */
-    boolean getAnyContainerStatus(@NotNull OfflinePlayer offline);
+  /**
+   * Get whether a user has SilentContainer mode enabled.
+   *
+   * @param offline the user to obtain the state of
+   * @return true if SilentContainer mode is enabled
+   */
+  boolean getSilentContainerStatus(OfflinePlayer offline);
 
-    /**
-     * @deprecated Use {@link #setAnyContainerStatus(OfflinePlayer, boolean)}. Not all containers are chests.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default void setPlayerAnyChestStatus(@NotNull OfflinePlayer offline, boolean status) {
-        setAnyContainerStatus(offline, status);
-    }
+  /**
+   * Set whether a user has SilentContainer mode enabled.
+   *
+   * @param offline the user to set the state of
+   * @param status the state of the mode
+   */
+  void setSilentContainerStatus(OfflinePlayer offline, boolean status);
 
-    /**
-     * Set whether a user has AnyContainer mode enabled.
-     *
-     * @param offline the user to set the state of
-     * @param status the state of the mode
-     */
-    void setAnyContainerStatus(@NotNull OfflinePlayer offline, boolean status);
+  /**
+   * Get an {@link ISpecialEnderChest} for a user.
+   *
+   * @param player the {@link Player} owning the inventory
+   * @param online whether the owner is currently online
+   * @return the created inventory
+   * @throws IllegalStateException if the server version is unsupported
+   * @throws InstantiationException if there was an issue creating the inventory
+   */
+  ISpecialEnderChest getSpecialEnderChest(
+      Player player,
+      boolean online
+  ) throws InstantiationException;
 
-    /**
-     * @deprecated Use {@link #getSilentContainerStatus(OfflinePlayer)}. Not all containers are chests.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default boolean getPlayerSilentChestStatus(@NotNull OfflinePlayer offline) {
-        return getSilentContainerStatus(offline);
-    }
+  /**
+   * Get an {@link ISpecialPlayerInventory} for a user.
+   *
+   * @param player the {@link Player} owning the inventory
+   * @param online whether the owner is currently online
+   * @return the created inventory
+   * @throws IllegalStateException if the server version is unsupported
+   * @throws InstantiationException if there was an issue creating the inventory
+   */
+  ISpecialPlayerInventory getSpecialInventory(
+      Player player,
+      boolean online
+  ) throws InstantiationException;
 
-    /**
-     * Get whether a user has SilentContainer mode enabled.
-     *
-     * @param offline the user to obtain the state of
-     * @return true if SilentContainer mode is enabled
-     */
-    boolean getSilentContainerStatus(@NotNull OfflinePlayer offline);
+  /**
+   * @deprecated Use {@link #openInventory(Player, ISpecialInventory, boolean)}
+   */
+  @Deprecated(forRemoval = true, since = "5.2.0")
+  @Nullable InventoryView openInventory(Player player, ISpecialInventory inventory);
 
-    /**
-     * @deprecated Use {@link #setSilentContainerStatus(OfflinePlayer, boolean)}. Not all containers are chests.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default void setPlayerSilentChestStatus(@NotNull OfflinePlayer offline, boolean status) {
-        setSilentContainerStatus(offline, status);
-    }
+  /**
+   * Open an {@link ISpecialInventory} for a {@link Player}.
+   *
+   * @param player the viewer
+   * @param inventory the inventory to open
+   * @param viewOnly whether the inventory should be view-only
+   * @return the resulting {@link InventoryView}
+   */
+  @Nullable InventoryView openInventory(Player player, ISpecialInventory inventory, boolean viewOnly);
 
-    /**
-     * Set whether a user has SilentContainer mode enabled.
-     *
-     * @param offline the user to set the state of
-     * @param status the state of the mode
-     */
-    void setSilentContainerStatus(@NotNull OfflinePlayer offline, boolean status);
+  /**
+   * Check if a {@link Player} is currently loaded by OpenInv.
+   *
+   * @param playerUuid the {@link UUID} of the {@code Player}
+   * @return whether the {@code Player} is loaded
+   * @since 4.2.0
+   */
+  boolean isPlayerLoaded(UUID playerUuid);
 
-    /**
-     * Get a unique identifier by which the OfflinePlayer can be referenced.
-     *
-     * @deprecated Use {@link OfflinePlayer#getUniqueId()} and {@link UUID#toString()}. This was necessary for non-UUID
-     * versions of Minecraft, but support for them has been dropped for years.
-     * @param offline the OfflinePlayer
-     * @return the identifier
-     * @throws IllegalStateException if the server version is unsupported
-     */
-    @Deprecated(forRemoval = true)
-    default @NotNull String getPlayerID(@NotNull OfflinePlayer offline) {
-        return offline.getUniqueId().toString();
-    }
+  /**
+   * Load a {@link Player} from an {@link OfflinePlayer}. If the user has not played before or the default world for
+   * the server is not loaded, this will return {@code null}.
+   *
+   * @param offline the {@code OfflinePlayer} to load a {@code Player} for
+   * @return the loaded {@code Player}
+   * @throws IllegalStateException if the server version is unsupported
+   */
+  @Nullable Player loadPlayer(final OfflinePlayer offline);
 
-    /**
-     * Get an {@link ISpecialEnderChest} for a user.
-     *
-     * @param player the {@link Player} owning the inventory
-     * @param online whether the owner is currently online
-     * @return the created inventory
-     * @throws IllegalStateException if the server version is unsupported
-     * @throws InstantiationException if there was an issue creating the inventory
-     */
-    @NotNull ISpecialEnderChest getSpecialEnderChest(@NotNull Player player, boolean online) throws InstantiationException;
+  /**
+   * Match an existing {@link OfflinePlayer}. If the name is a {@link UUID#toString() UUID string}, this will only
+   * return the user if they have actually played on the server before, unlike {@link Bukkit#getOfflinePlayer(UUID)}.
+   *
+   * <p>This method is potentially very heavily blocking. It should not ever be called on the
+   * main thread, and if it is, a stack trace will be displayed alerting server owners to the
+   * call.
+   *
+   * @param name the string to match
+   * @return the user with the closest matching name
+   */
+  @Nullable OfflinePlayer matchPlayer(String name);
 
-    /**
-     * Get an {@link ISpecialPlayerInventory} for a user.
-     *
-     * @param player the {@link Player} owning the inventory
-     * @param online whether the owner is currently online
-     * @return the created inventory
-     * @throws IllegalStateException if the server version is unsupported
-     * @throws InstantiationException if there was an issue creating the inventory
-     */
-    @NotNull ISpecialPlayerInventory getSpecialInventory(@NotNull Player player, boolean online) throws InstantiationException;
+  /**
+   * Forcibly close inventories of and unload any cached data for a user.
+   *
+   * @param offline the {@link OfflinePlayer} to unload
+   */
+  void unload(OfflinePlayer offline);
 
-    /**
-     * Open an {@link ISpecialInventory} for a {@link Player}.
-     *
-     * @param player the viewer
-     * @param inventory the inventory to open
-     * @return the resulting {@link InventoryView}
-     */
-    @Nullable InventoryView openInventory(@NotNull Player player, @NotNull ISpecialInventory inventory);
-
-    /**
-     * Check if a {@link Player} is currently loaded by OpenInv.
-     *
-     * @param playerUuid the {@link UUID} of the {@code Player}
-     * @return whether the {@code Player} is loaded
-     * @since 4.2.0
-     */
-    boolean isPlayerLoaded(@NotNull UUID playerUuid);
-
-    /**
-     * Load a {@link Player} from an {@link OfflinePlayer}. If the user has not played before or the default world for
-     * the server is not loaded, this will return {@code null}.
-     *
-     * @param offline the {@code OfflinePlayer} to load a {@code Player} for
-     * @return the loaded {@code Player}
-     * @throws IllegalStateException if the server version is unsupported
-     */
-    @Nullable Player loadPlayer(@NotNull final OfflinePlayer offline);
-
-    /**
-     * Match an existing {@link OfflinePlayer}. If the name is a {@link UUID#toString() UUID string}, this will only
-     * return the user if they have actually played on the server before, unlike {@link Bukkit#getOfflinePlayer(UUID)}.
-     *
-     * <p>This method is potentially very heavily blocking. It should not ever be called on the
-     * main thread, and if it is, a stack trace will be displayed alerting server owners to the
-     * call.
-     *
-     * @param name the string to match
-     * @return the user with the closest matching name
-     */
-    @Nullable OfflinePlayer matchPlayer(@NotNull String name);
-
-    /**
-     * @deprecated OpenInv uses action bar chat for notifications. Whether they show is based on language settings.
-     */
-    @Deprecated(forRemoval = true)
-    default boolean notifyAnyChest() {
-        return true;
-    }
-
-    /**
-     * @deprecated OpenInv uses action bar chat for notifications. Whether they show is based on language settings.
-     */
-    @Deprecated(forRemoval = true)
-    default boolean notifySilentChest() {
-        return true;
-    }
-
-    /**
-     * @deprecated see {@link #retainPlayer(Player, Plugin)}
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default void releasePlayer(@NotNull Player player, @NotNull Plugin plugin) {}
-
-    /**
-     * @deprecated OpenInv no longer uses an internal cache beyond maintaining copies of currently open inventories.
-     * If you wish to use/modify a player, ensure either {@link IOpenInv#isPlayerLoaded(UUID)} is false or the player
-     * instance is the same memory address as the one in use by OpenInv.
-     * <pre>
-     *  public &#64;NotNull Player savePlayerData(&#64;NotNull Player player) {
-     *     IOpenInv openInv = ...
-     *     if (!openInv.disableSaving() && openInv.isPlayerLoaded(player.getUniqueId())) {
-     *         Player openInvLoadedPlayer = openInv.loadPlayer(myInUsePlayer);
-     *         if (openInvLoadedPlayer != player) {
-     *             // The copy loaded by OpenInv is not the same as our loaded copy. Push our changes.
-     *             copyPlayerModifications(player, openInvLoadedPlayer);
-     *         }
-     *         // OpenInv will handle saving data when the player is unloaded.
-     *         // Optionally, to be sure our changes will persist, save now.
-     *         // openInvLoadedPlayer.saveData();
-     *         return openInvLoadedPlayer;
-     *     }
-     *
-     *     player.saveData();
-     *     return player;
-     * }
-     * </pre>
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default void retainPlayer(@NotNull Player player, @NotNull Plugin plugin) {}
-
-    /**
-     * Forcibly close inventories of and unload any cached data for a user.
-     *
-     * @param offline the {@link OfflinePlayer} to unload
-     */
-    void unload(@NotNull OfflinePlayer offline);
-
-    Logger getLogger();
+  Logger getLogger();
 
 }

api/src/main/java/com/lishid/openinv/event/OpenPlayerSaveEvent.java

@@ -1,35 +1,39 @@
 package com.lishid.openinv.event;
 
+import com.google.errorprone.annotations.RestrictedApi;
 import com.lishid.openinv.internal.ISpecialInventory;
 import org.bukkit.entity.Player;
-import org.bukkit.event.Cancellable;
-import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
-import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
 
 /**
- * Event fired before OpenInv saves a player's data.
+ * Event fired before OpenInv saves a player's data when closing an {@link ISpecialInventory}.
  */
-public class OpenPlayerSaveEvent extends Event implements Cancellable {
+@NullMarked
+public class OpenPlayerSaveEvent extends PlayerSaveEvent {
 
   private static final HandlerList HANDLERS = new HandlerList();
 
-  private final Player player;
   private final ISpecialInventory inventory;
-  private boolean cancelled = false;
-
-  public OpenPlayerSaveEvent(@NotNull Player player, @NotNull ISpecialInventory inventory) {
-    this.player = player;
-    this.inventory = inventory;
-  }
 
   /**
-   * Get the {@link Player} whose data is being saved.
+   * Construct a new {@code OpenPlayerSaveEvent}.
    *
-   * @return player the Player whose data is being saved
+   * <p>The constructor is not considered part of the API, and may be subject to change.</p>
+   *
+   * @param player the player to be saved
+   * @param inventory the {@link ISpecialInventory} being closed
    */
-  public @NotNull Player getPlayer() {
-    return player;
+  @RestrictedApi(
+      explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/event/OpenEvents.java"
+  )
+  @ApiStatus.Internal
+  OpenPlayerSaveEvent(Player player, ISpecialInventory inventory) {
+    super(player);
+    this.inventory = inventory;
   }
 
   /**
@@ -37,31 +41,10 @@ public class OpenPlayerSaveEvent extends Event implements Cancellable {
    *
    * @return the special inventory
    */
-  public @NotNull ISpecialInventory getInventory() {
+  public ISpecialInventory getInventory() {
     return inventory;
   }
 
-  /**
-   * Get whether the event is cancelled.
-   *
-   * @return true if the event is cancelled
-   */
-  @Override
-  public boolean isCancelled() {
-    return cancelled;
-  }
-
-  /**
-   * Set whether the event is cancelled.
-   *
-   * @param cancel whether the event is cancelled
-   */
-  @Override
-  public void setCancelled(boolean cancel) {
-    this.cancelled = cancel;
-  }
-
-  @NotNull
   @Override
   public HandlerList getHandlers() {
     return HANDLERS;

api/src/main/java/com/lishid/openinv/event/PlayerSaveEvent.java

@@ -0,0 +1,68 @@
+package com.lishid.openinv.event;
+
+
+import com.google.errorprone.annotations.RestrictedApi;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Event fired before a {@link Player} loaded via OpenInv is saved.
+ */
+@NullMarked
+public class PlayerSaveEvent extends PlayerEvent implements Cancellable {
+
+  private static final HandlerList HANDLERS = new HandlerList();
+
+  private boolean cancelled = false;
+
+  /**
+   * Construct a new {@code PlayerSaveEvent}.
+   *
+   * <p>The constructor is not considered part of the API, and may be subject to change.</p>
+   *
+   * @param player the player to be saved
+   */
+  @RestrictedApi(
+      explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/event/(OpenPlayerSaveEvent|OpenEvents).java"
+  )
+  @ApiStatus.Internal
+  PlayerSaveEvent(Player player) {
+    super(player);
+  }
+
+  /**
+   * Get whether the event is cancelled.
+   *
+   * @return true if the event is cancelled
+   */
+  @Override
+  public boolean isCancelled() {
+    return cancelled;
+  }
+
+  /**
+   * Set whether the event is cancelled.
+   *
+   * @param cancel whether the event is cancelled
+   */
+  @Override
+  public void setCancelled(boolean cancel) {
+    this.cancelled = cancel;
+  }
+
+  @Override
+  public HandlerList getHandlers() {
+    return HANDLERS;
+  }
+
+  public static HandlerList getHandlerList() {
+    return HANDLERS;
+  }
+
+}

api/src/main/java/com/lishid/openinv/event/PlayerToggledEvent.java

@@ -0,0 +1,72 @@
+package com.lishid.openinv.event;
+
+import com.google.errorprone.annotations.RestrictedApi;
+import com.lishid.openinv.util.setting.PlayerToggle;
+import org.bukkit.event.Event;
+import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.UUID;
+
+/**
+ * Event fired after OpenInv modifies a toggleable setting for a player.
+ */
+@NullMarked
+public class PlayerToggledEvent extends Event {
+
+  private static final HandlerList HANDLERS = new HandlerList();
+
+  private final PlayerToggle toggle;
+  private final UUID uuid;
+  private final boolean enabled;
+
+  @RestrictedApi(
+      explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/event/OpenEvents.java"
+  )
+  @ApiStatus.Internal
+  PlayerToggledEvent(PlayerToggle toggle, UUID uuid, boolean enabled) {
+    this.toggle = toggle;
+    this.uuid = uuid;
+    this.enabled = enabled;
+  }
+
+  /**
+   * Get the {@link PlayerToggle} affected.
+   *
+   * @return the toggle
+   */
+  public PlayerToggle getToggle() {
+    return toggle;
+  }
+
+  /**
+   * Get the {@link UUID} of the player whose setting was changed.
+   *
+   * @return the player ID
+   */
+  public UUID getPlayerId() {
+    return uuid;
+  }
+
+  /**
+   * Get whether the toggle is enabled.
+   *
+   * @return true if the toggle is enabled
+   */
+  public boolean isEnabled() {
+    return enabled;
+  }
+
+  @Override
+  public HandlerList getHandlers() {
+    return HANDLERS;
+  }
+
+  public static HandlerList getHandlerList() {
+    return HANDLERS;
+  }
+
+}

api/src/main/java/com/lishid/openinv/internal/IAnySilentContainer.java

@@ -16,182 +16,118 @@
 
 package com.lishid.openinv.internal;
 
-import org.bukkit.block.Barrel;
 import org.bukkit.block.Block;
 import org.bukkit.block.BlockFace;
 import org.bukkit.block.BlockState;
 import org.bukkit.block.EnderChest;
-import org.bukkit.block.ShulkerBox;
-import org.bukkit.block.data.BlockData;
 import org.bukkit.block.data.Directional;
-import org.bukkit.block.data.type.Chest;
 import org.bukkit.entity.Cat;
 import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.InventoryHolder;
 import org.bukkit.util.BoundingBox;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
+@NullMarked
 public interface IAnySilentContainer {
 
-    /**
-     * Forcibly open the container at the given coordinates for the Player. This will open blocked containers! Be sure
-     * to check {@link #isAnyContainerNeeded(Block)} first if that is not desirable.
-     *
-     * @param player the {@link Player} opening the container
-     * @param silent whether the container's noise is to be silenced
-     * @param block  the {@link Block} of the container
-     * @return true if the container can be opened
-     */
-    boolean activateContainer(@NotNull Player player, boolean silent, @NotNull Block block);
+  /**
+   * Forcibly open the container at the given coordinates for the Player. This will open blocked containers! Be sure
+   * to check {@link #isAnyContainerNeeded(Block)} first if that is not desirable.
+   *
+   * @param player the {@link Player} opening the container
+   * @param silent whether the container's noise is to be silenced
+   * @param block  the {@link Block} of the container
+   * @return true if the container can be opened
+   */
+  boolean activateContainer(Player player, boolean silent, Block block);
 
-    /**
-     * Perform operations required to close the current container silently.
-     *
-     * @param player the {@link Player} closing a container
-     */
-    void deactivateContainer(@NotNull Player player);
+  /**
+   * Perform operations required to close the current container silently.
+   *
+   * @param player the {@link Player} closing a container
+   */
+  void deactivateContainer(Player player);
 
-    /**
-     * @param player the player opening the container
-     * @param block  the {@link Block} of the container
-     * @return true if the container is blocked
-     * @deprecated use {@link #isAnyContainerNeeded(Block)}
-     */
-    @Deprecated(forRemoval = true, since = "4.1.9")
-    default boolean isAnyContainerNeeded(@NotNull Player player, @NotNull Block block) {
-        return isAnyContainerNeeded(block);
-    }
+  /**
+   * Check if the container at the given coordinates is blocked.
+   *
+   * @param block the {@link Block} of the container
+   * @return true if the container is blocked
+   */
+  boolean isAnyContainerNeeded(Block block);
 
-    /**
-     * Check if the container at the given coordinates is blocked.
-     *
-     * @param block the {@link Block} of the container
-     * @return true if the container is blocked
-     */
-    default boolean isAnyContainerNeeded(@NotNull Block block) {
-        BlockState blockState = block.getState();
+  /**
+   * Check if a shulker box block cannot be opened under ordinary circumstances.
+   *
+   * @param shulkerBox the shulker box block
+   * @return whether the container is blocked
+   */
+  default boolean isShulkerBlocked(Block shulkerBox) {
+    Directional directional = (Directional) shulkerBox.getBlockData();
+    BlockFace facing = directional.getFacing();
+    // Construct a new 1-block bounding box at the origin.
+    BoundingBox box = new BoundingBox(0, 0, 0, 1, 1, 1);
+    // Expand the box in the direction the shulker will open.
+    box.expand(facing, 0.5);
+    // Move the box away from the origin by a block so only the expansion intersects with a box around the origin.
+    box.shift(facing.getOppositeFace().getDirection());
+    // Check if the relative block's collision shape (which will be at the origin) intersects with the expanded box.
+    return shulkerBox.getRelative(facing).getCollisionShape().overlaps(box);
+  }
 
-        // Barrels do not require AnyContainer.
-        if (blockState instanceof Barrel) {
-            return false;
-        }
+  /**
+   * Check if a chest cannot be opened under ordinary circumstances.
+   *
+   * @param chest the chest block
+   * @return whether the container is blocked
+   */
+  default boolean isChestBlocked(Block chest) {
+    org.bukkit.block.Block relative = chest.getRelative(0, 1, 0);
+    return relative.getType().isOccluding()
+        || !chest.getWorld().getNearbyEntities(BoundingBox.of(relative), Cat.class::isInstance).isEmpty();
+  }
 
-        // Enderchests require a non-occluding block on top to open.
-        if (blockState instanceof EnderChest) {
-            return block.getRelative(0, 1, 0).getType().isOccluding();
-        }
+  /**
+   * Check if the given {@link Block} is a container which can be unblocked or silenced.
+   *
+   * @param block the potential container
+   * @return true if the type is a supported container
+   */
+  boolean isAnySilentContainer(Block block);
 
-        // Shulker boxes require half a block clear in the direction they open.
-        if (blockState instanceof ShulkerBox) {
-            return isShulkerBlocked(block);
-        }
+  /**
+   * Check if the given {@link BlockState} is a container which can be unblocked or silenced.
+   *
+   * @param blockState the potential container
+   * @return true if the type is a supported container
+   */
+  default boolean isAnySilentContainer(BlockState blockState) {
+    return (blockState instanceof InventoryHolder holder && isAnySilentContainer(holder))
+        || blockState instanceof EnderChest;
+  }
 
-        if (!(blockState instanceof org.bukkit.block.Chest)) {
-            return false;
-        }
+  /**
+   * Check if the given {@link InventoryHolder} is a container which can be unblocked or silenced.
+   *
+   * @param holder the potential container
+   * @return true if the type is a supported container
+   */
+  default boolean isAnySilentContainer(@Nullable InventoryHolder holder) {
+    return holder instanceof org.bukkit.block.EnderChest
+        || holder instanceof org.bukkit.block.Chest
+        || holder instanceof org.bukkit.block.DoubleChest
+        || holder instanceof org.bukkit.block.ShulkerBox
+        || holder instanceof org.bukkit.block.Barrel;
+  }
 
-        if (isChestBlocked(block)) {
-            return true;
-        }
-
-        BlockData blockData = block.getBlockData();
-        if (!(blockData instanceof Chest chest) || ((Chest) blockData).getType() == Chest.Type.SINGLE) {
-            return false;
-        }
-
-        int ordinal = (chest.getFacing().ordinal() + 4 + (chest.getType() == Chest.Type.RIGHT ? -1 : 1)) % 4;
-        BlockFace relativeFace = BlockFace.values()[ordinal];
-        org.bukkit.block.Block relative = block.getRelative(relativeFace);
-
-        if (relative.getType() != block.getType()) {
-            return false;
-        }
-
-        BlockData relativeData = relative.getBlockData();
-        if (!(relativeData instanceof Chest relativeChest)) {
-            return false;
-        }
-
-        if (relativeChest.getFacing() != chest.getFacing()
-                || relativeChest.getType() != (chest.getType() == Chest.Type.RIGHT ? Chest.Type.LEFT : Chest.Type.RIGHT)) {
-            return false;
-        }
-
-        return isChestBlocked(relative);
-    }
-
-    /**
-     * Check if a {@link ShulkerBox} cannot be opened under ordinary circumstances.
-     *
-     * @deprecated Use {@link #isShulkerBlocked(Block)}.
-     * @param shulkerBox the shulker box container
-     * @return whether the container is blocked
-     */
-    @Deprecated(since = "4.4.4", forRemoval = true)
-    default boolean isShulkerBlocked(@NotNull ShulkerBox shulkerBox) {
-        return isShulkerBlocked(shulkerBox.getBlock());
-    }
-
-    /**
-     * Check if a shulker box block cannot be opened under ordinary circumstances.
-     *
-     * @param shulkerBox the shulker box block
-     * @return whether the container is blocked
-     */
-    default boolean isShulkerBlocked(@NotNull Block shulkerBox) {
-        Directional directional = (Directional) shulkerBox.getBlockData();
-        BlockFace facing = directional.getFacing();
-        BoundingBox box = new BoundingBox(0, 0, 0, 1, 1, 1);
-        box.expand(facing, 0.5);
-        box.shift(facing.getOppositeFace().getDirection());
-        return shulkerBox.getRelative(facing).getCollisionShape().overlaps(box);
-    }
-
-    /**
-     * Check if a chest cannot be opened under ordinary circumstances.
-     *
-     * @param chest the chest block
-     * @return whether the container is blocked
-     */
-    default boolean isChestBlocked(@NotNull Block chest) {
-        org.bukkit.block.Block relative = chest.getRelative(0, 1, 0);
-        return relative.getType().isOccluding()
-                || !chest.getWorld().getNearbyEntities(BoundingBox.of(relative), Cat.class::isInstance).isEmpty();
-    }
-
-    /**
-     * Check if the given {@link Block} is a container which can be unblocked or silenced.
-     *
-     * @param block the potential container
-     * @return true if the type is a supported container
-     */
-    default boolean isAnySilentContainer(@NotNull Block block) {
-        return isAnySilentContainer(block.getState());
-    }
-
-    /**
-     * Check if the given {@link BlockState} is a container which can be unblocked or silenced.
-     *
-     * @param blockState the potential container
-     * @return true if the type is a supported container
-     */
-    default boolean isAnySilentContainer(@NotNull BlockState blockState) {
-        return blockState instanceof InventoryHolder holder && isAnySilentContainer(holder)
-                || blockState instanceof EnderChest;
-    }
-
-    /**
-     * Check if the given {@link InventoryHolder} is a container which can be unblocked or silenced.
-     *
-     * @param holder the potential container
-     * @return true if the type is a supported container
-     */
-    default boolean isAnySilentContainer(@NotNull InventoryHolder holder) {
-        return holder instanceof org.bukkit.block.EnderChest
-                || holder instanceof org.bukkit.block.Chest
-                || holder instanceof org.bukkit.block.DoubleChest
-                || holder instanceof org.bukkit.block.ShulkerBox
-                || holder instanceof org.bukkit.block.Barrel;
-    }
+  /**
+   * Check if the given {@link Inventory} belongs to a container which can be unblocked or silenced.
+   * 
+   * @param inventory the potential container inventory
+   * @return true if the type is a supported container
+   */
+  boolean isAnySilentContainer(Inventory inventory);
 
 }

api/src/main/java/com/lishid/openinv/internal/IInventoryAccess.java

@@ -1,62 +0,0 @@
-/*
- * Copyright (C) 2011-2022 lishid. All rights reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.internal;
-
-import com.lishid.openinv.util.InventoryAccess;
-import org.bukkit.inventory.Inventory;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-
-/**
- * @deprecated Use static {@link InventoryAccess} methods.
- */
-@Deprecated(forRemoval = true)
-public interface IInventoryAccess {
-
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default @Nullable ISpecialEnderChest getSpecialEnderChest(@NotNull Inventory inventory) {
-        return InventoryAccess.getEnderChest(inventory);
-    }
-
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default @Nullable ISpecialPlayerInventory getSpecialPlayerInventory(@NotNull Inventory inventory) {
-        return InventoryAccess.getPlayerInventory(inventory);
-    }
-
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default boolean isSpecialEnderChest(@NotNull Inventory inventory) {
-        return InventoryAccess.isEnderChest(inventory);
-    }
-
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default boolean isSpecialPlayerInventory(@NotNull Inventory inventory) {
-        return InventoryAccess.isPlayerInventory(inventory);
-    }
-
-}

api/src/main/java/com/lishid/openinv/internal/ISpecialEnderChest.java

@@ -16,9 +16,18 @@
 
 package com.lishid.openinv.internal;
 
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
 /**
  * An {@link ISpecialInventory} representing an ender chest.
  */
+@NullMarked
 public interface ISpecialEnderChest extends ISpecialInventory {
 
+  @Override
+  default InventoryType getBukkitType() {
+    return InventoryType.ENDER_CHEST;
+  }
+
 }

api/src/main/java/com/lishid/openinv/internal/ISpecialInventory.java

@@ -18,47 +18,59 @@ package com.lishid.openinv.internal;
 
 import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.Player;
+import org.bukkit.event.inventory.InventoryType;
 import org.bukkit.inventory.Inventory;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * Interface defining behavior for special inventories backed by other inventories' content listings.
  */
+@NullMarked
 public interface ISpecialInventory {
 
-    /**
-     * Get the {@link Inventory} associated with this {@code ISpecialInventory}.
-     *
-     * @return the Bukkit inventory
-     */
-    @NotNull Inventory getBukkitInventory();
+  /**
+   * Get the {@link Inventory} associated with this {@code ISpecialInventory}.
+   *
+   * @return the Bukkit inventory
+   */
+  Inventory getBukkitInventory();
 
-    /**
-     * Set the owning {@link Player} instance to a newly-joined user.
-     *
-     * @param player the user coming online
-     */
-    void setPlayerOnline(@NotNull Player player);
+  /**
+   * Get the {@link InventoryType} corresponding to this {@code ISpecialInventory}.
+   *
+   * @return the type of Bukkit inventory
+   */
+  InventoryType getBukkitType();
 
-    /**
-     * Mark the owner of the inventory offline.
-     */
-    void setPlayerOffline();
+  /**
+   * Set the owning {@link Player} instance to a newly-joined user.
+   *
+   * @param player the user coming online
+   */
+  void setPlayerOnline(Player player);
 
-    /**
-     * Get whether the inventory is being viewed by any users.
-     *
-     * @return true if the inventory is being viewed
-     */
-    default boolean isInUse() {
-        return !getBukkitInventory().getViewers().isEmpty();
-    }
+  /**
+   * Mark the owner of the inventory offline.
+   *
+   * @deprecated No longer used by implementations.
+   */
+  @Deprecated(forRemoval = true, since = "5.1.11")
+  default void setPlayerOffline() {}
 
-    /**
-     * Get the {@link Player} who owns the inventory.
-     *
-     * @return the {@link HumanEntity} who owns the inventory
-     */
-    @NotNull HumanEntity getPlayer();
+  /**
+   * Get whether the inventory is being viewed by any users.
+   *
+   * @return true if the inventory is being viewed
+   */
+  default boolean isInUse() {
+    return !getBukkitInventory().getViewers().isEmpty();
+  }
+
+  /**
+   * Get the {@link Player} who owns the inventory.
+   *
+   * @return the {@link HumanEntity} who owns the inventory
+   */
+  HumanEntity getPlayer();
 
 }

api/src/main/java/com/lishid/openinv/internal/ISpecialPlayerInventory.java

@@ -16,35 +16,18 @@
 
 package com.lishid.openinv.internal;
 
-import java.util.List;
-import org.bukkit.entity.HumanEntity;
-import org.bukkit.inventory.Inventory;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * An {@link ISpecialInventory} representing a player inventory.
  */
+@NullMarked
 public interface ISpecialPlayerInventory extends ISpecialInventory {
 
-    /*
-     * Player inventory usage varies from all other inventories - as the inventory is technically open at all times,
-     * if the player is online or has been online while the inventory is open, they are in the viewer list.
-     */
-    @Override
-    default boolean isInUse() {
-        Inventory inventory = getBukkitInventory();
-        List<HumanEntity> viewers = inventory.getViewers();
-
-        if (viewers.size() != 1) {
-            return !viewers.isEmpty();
-        }
-
-        HumanEntity viewer = viewers.get(0);
-
-        if (!viewer.getUniqueId().equals(getPlayer().getUniqueId())) {
-            return true;
-        }
-
-        return viewer.getOpenInventory().getTopInventory().equals(inventory);
-    }
+  @Override
+  default InventoryType getBukkitType() {
+    return InventoryType.PLAYER;
+  }
 
 }

api/src/main/java/com/lishid/openinv/util/InventoryAccess.java

@@ -16,108 +16,93 @@
 
 package com.lishid.openinv.util;
 
-import com.lishid.openinv.internal.IInventoryAccess;
+import com.google.errorprone.annotations.RestrictedApi;
 import com.lishid.openinv.internal.ISpecialEnderChest;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import java.lang.reflect.Method;
-import org.bukkit.Bukkit;
 import org.bukkit.inventory.Inventory;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
-public final class InventoryAccess implements IInventoryAccess {
+import java.util.function.BiFunction;
 
-    private static Class<?> craftInventory = null;
-    private static Method getInventory = null;
+@NullMarked
+public final class InventoryAccess {
 
-    static {
-        String packageName = Bukkit.getServer().getClass().getPackage().getName();
-        try {
-            craftInventory = Class.forName(packageName + ".inventory.CraftInventory");
-            getInventory = craftInventory.getDeclaredMethod("getInventory");
-        } catch (ClassNotFoundException | NoSuchMethodException ignored) {}
-    }
+  private static @Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, @Nullable ISpecialInventory> provider;
 
-    /**
-     * @deprecated use {@link #isUsable()}
-     */
-    @Deprecated(forRemoval = true)
-    public static boolean isUseable() {
-        return isUsable();
-    }
+  public static boolean isUsable() {
+    return provider != null;
+  }
 
-    public static boolean isUsable() {
-        return craftInventory != null && getInventory != null;
-    }
+  /**
+   * Check if an {@link Inventory} is an {@link ISpecialPlayerInventory} implementation.
+   *
+   * @param inventory the Bukkit inventory
+   * @return true if backed by the correct implementation
+   */
+  public static boolean isPlayerInventory(Inventory inventory) {
+    return getPlayerInventory(inventory) != null;
+  }
 
-    /**
-     * Check if an {@link Inventory} is an {@link ISpecialPlayerInventory} implementation.
-     *
-     * @param inventory the Bukkit inventory
-     * @return true if backed by the correct implementation
-     */
-    public static boolean isPlayerInventory(@NotNull Inventory inventory) {
-        return getPlayerInventory(inventory) != null;
-    }
+  /**
+   * Get the {@link ISpecialPlayerInventory} backing an {@link Inventory}. Returns {@code null} if the inventory is
+   * not backed by the correct class.
+   *
+   * @param inventory the Bukkit inventory
+   * @return the backing implementation if available
+   */
+  public static @Nullable ISpecialPlayerInventory getPlayerInventory(Inventory inventory) {
+    return provider == null ? null : (ISpecialPlayerInventory) provider.apply(inventory, ISpecialPlayerInventory.class);
+  }
 
-    /**
-     * Get the {@link ISpecialPlayerInventory} backing an {@link Inventory}. Returns {@code null} if the inventory is
-     * not backed by the correct class.
-     *
-     * @param inventory the Bukkit inventory
-     * @return the backing implementation if available
-     */
-    public static @Nullable ISpecialPlayerInventory getPlayerInventory(@NotNull Inventory inventory) {
-        return getSpecialInventory(ISpecialPlayerInventory.class, inventory);
-    }
+  /**
+   * Check if an {@link Inventory} is an {@link ISpecialEnderChest} implementation.
+   *
+   * @param inventory the Bukkit inventory
+   * @return true if backed by the correct implementation
+   */
+  public static boolean isEnderChest(Inventory inventory) {
+    return getEnderChest(inventory) != null;
+  }
 
-    /**
-     * Check if an {@link Inventory} is an {@link ISpecialEnderChest} implementation.
-     *
-     * @param inventory the Bukkit inventory
-     * @return true if backed by the correct implementation
-     */
-    public static boolean isEnderChest(@NotNull Inventory inventory) {
-        return getEnderChest(inventory) != null;
-    }
+  /**
+   * Get the {@link ISpecialEnderChest} backing an {@link Inventory}. Returns {@code null} if the inventory is
+   * not backed by the correct class.
+   *
+   * @param inventory the Bukkit inventory
+   * @return the backing implementation if available
+   */
+  public static @Nullable ISpecialEnderChest getEnderChest(Inventory inventory) {
+    return provider == null ? null : (ISpecialEnderChest) provider.apply(inventory, ISpecialEnderChest.class);
+  }
 
-    /**
-     * Get the {@link ISpecialEnderChest} backing an {@link Inventory}. Returns {@code null} if the inventory is
-     * not backed by the correct class.
-     *
-     * @param inventory the Bukkit inventory
-     * @return the backing implementation if available
-     */
-    public static @Nullable ISpecialEnderChest getEnderChest(@NotNull Inventory inventory) {
-        return getSpecialInventory(ISpecialEnderChest.class, inventory);
-    }
+  /**
+   * Get a {@link ISpecialInventory} backing an {@link Inventory}. Returns {@code null} if the inventory is not backed
+   * by the correct class.
+   *
+   * @param inventory the Bukkit inventory
+   * @return the backing implementation if available
+   */
+  public static @Nullable ISpecialInventory getInventory(Inventory inventory) {
+    return provider == null ? null : provider.apply(inventory, ISpecialInventory.class);
+  }
 
-    private static <T extends ISpecialInventory> @Nullable T getSpecialInventory(@NotNull Class<T> expected, @NotNull Inventory inventory) {
-        Object inv;
-        if (isUsable() && craftInventory.isAssignableFrom(inventory.getClass())) {
-            try {
-                inv = getInventory.invoke(inventory);
-                if (expected.isInstance(inv)) {
-                    return expected.cast(inv);
-                }
-            } catch (ReflectiveOperationException ignored) {}
-        }
+  @RestrictedApi(
+      explanation = "Not part of the API.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/util/InternalAccessor.java"
+  )
+  @ApiStatus.Internal
+  static void setProvider(
+      @Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, @Nullable ISpecialInventory> provider
+  ) {
+    InventoryAccess.provider = provider;
+  }
 
-        // Use reflection to find the IInventory
-        inv = ReflectionHelper.grabObjectByType(inventory, expected);
-
-        if (expected.isInstance(inv)) {
-            return expected.cast(inv);
-        }
-
-        return null;
-    }
-
-    /**
-     * @deprecated Do not create a new instance to use static methods.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    public InventoryAccess() {}
+  private InventoryAccess() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
 
 }

api/src/main/java/com/lishid/openinv/util/Permissions.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util;
+
+import org.bukkit.permissions.Permissible;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * An enum containing all permissions directly checked by OpenInv.
+ *
+ * <p>Note that this is not an exhaustive list! This does not contain
+ * all permissions managed by Bukkit, largely parent nodes.</p>
+ */
+@NullMarked
+public enum Permissions {
+
+  /// Permission to open one's own inventory.
+  INVENTORY_OPEN_SELF("inventory.open.self"),
+  /// Permission to open someone else's inventory.
+  INVENTORY_OPEN_OTHER("inventory.open.other"),
+  /**
+   * Permission to edit one's own inventory.
+   *
+   * <p>Note that this does not guarantee that the user has access to open the inventory!
+   * Be sure to check {@link #INVENTORY_OPEN_SELF} first.</p>
+   */
+  INVENTORY_EDIT_SELF("inventory.edit.self"),
+  /**
+   * Permission to edit someone else's inventory.
+   *
+   * <p>Note that this does not guarantee that the user has access to open the inventory!
+   * Be sure to check {@link #INVENTORY_OPEN_OTHER} first.</p>
+   */
+  INVENTORY_EDIT_OTHER("inventory.edit.other"),
+  /// Permission to insert any item into the head slot.
+  INVENTORY_SLOT_HEAD_ANY("inventory.slot.head.any"),
+  /// Permission to insert any item into the chest slot.
+  INVENTORY_SLOT_CHEST_ANY("inventory.slot.chest.any"),
+  /// Permission to insert any item into the legs slot.
+  INVENTORY_SLOT_LEGS_ANY("inventory.slot.legs.any"),
+  /// Permission to insert any item into the feet slot.
+  INVENTORY_SLOT_FEET_ANY("inventory.slot.feet.any"),
+  /// Permission to drop items as the player via the drop slot.
+  INVENTORY_SLOT_DROP("inventory.slot.drop"),
+
+  /// Permission to open one's own ender chest.
+  ENDERCHEST_OPEN_SELF("enderchest.open.self"),
+  /// Permission to open someone else's ender chest.
+  ENDERCHEST_OPEN_OTHER("enderchest.open.other"),
+  /**
+   * Permission to edit one's own ender chest.
+   *
+   * <p>Note that this does not guarantee that the user has access to open the inventory!
+   * Be sure to check {@link #ENDERCHEST_OPEN_SELF} first.</p>
+   */
+  ENDERCHEST_EDIT_SELF("enderchest.edit.self"),
+  /**
+   * Permission to edit someone else's ender chest.
+   *
+   * <p>Note that this does not guarantee that the user has access to open the inventory!
+   * Be sure to check {@link #ENDERCHEST_OPEN_OTHER} first.</p>
+   */
+  ENDERCHEST_EDIT_OTHER("enderchest.edit.other"),
+
+  /// Permission to clear one's own inventory.
+  CLEAR_SELF("clear.self"),
+  /// Permission to clear someone else's inventory.
+  CLEAR_OTHER("clear.other"),
+
+  /// Permission to view inventories and ender chests from other worlds.
+  ACCESS_CROSSWORLD("access.crossworld"),
+  /// Permission to access offline players' inventories and ender chests.
+  ACCESS_OFFLINE("access.offline"),
+  /// Permission to access online players' inventories and ender chests.
+  ACCESS_ONLINE("access.online"),
+  /// Permission granting the ability to edit players with the same access level.
+  ACCESS_EQUAL_EDIT("access.equal.edit"),
+  /// Permission to view, but not edit, players with the same access level.
+  ACCESS_EQUAL_VIEW("access.equal.view"),
+  /// Permission to deny access to players with the same access level.
+  ACCESS_EQUAL_DENY("access.equal.deny"),
+
+  /// Permission to perform inventory interaction while in spectator mode.
+  SPECTATE_CLICK("spectate.click"),
+
+  /// Permission to use the AnyContainer feature.
+  CONTAINER_ANY("container.any"),
+  /// Permission to use the AnyContainer feature but not the command to toggle it.
+  CONTAINER_ANY_USE("container.any.use"),
+  /// Permission to use the SilentContainer feature.
+  CONTAINER_SILENT("container.silent"),
+  /// Permission to use the SilentContainer feature but not the command to toggle it.
+  CONTAINER_SILENT_USE("container.silent.use"),
+  /// Permission to search inventories and ender chests.
+  SEARCH_INVENTORY("search.inventory"),
+  /// Permission to search containers.
+  SEARCH_CONTAINER("search.container");
+
+  private final String permission;
+
+  Permissions(String permission) {
+    this.permission = "openinv." + permission;
+  }
+
+  /**
+   * Check if a {@link Permissible} has this permission.
+   *
+   * @param permissible the Permissible
+   * @return true if the permission is granted
+   */
+  public boolean hasPermission(Permissible permissible) {
+    return permissible.hasPermission(permission);
+  }
+
+}

api/src/main/java/com/lishid/openinv/util/ReflectionHelper.java

@@ -1,75 +0,0 @@
-/*
- * Copyright (C) 2011-2021 lishid. All rights reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.util;
-
-import java.lang.reflect.Field;
-import org.jetbrains.annotations.Nullable;
-
-/**
- * A utility for making reflection easier.
- */
-public final class ReflectionHelper {
-
-    private ReflectionHelper() {}
-
-    /**
-     * Grab an {@link Object} stored in a {@link Field} of another {@code Object}.
-     *
-     * <p>This casts the field to the correct class. Any issues will result in a {@code null} return value.
-     *
-     * @param fieldType the {@link Class} of {@code Object} stored in the {@code Field}
-     * @param holder the containing {@code Object}
-     * @param <T> the type of stored {@code Object}
-     * @return the first matching {@code Object} or {@code null} if none match
-     */
-    public static <T> @Nullable T grabObjectByType(final Object holder, final Class<T> fieldType) {
-        Field field = grabFieldByType(holder.getClass(), fieldType);
-
-        if (field != null) {
-            try {
-                return fieldType.cast(field.get(holder));
-            } catch (IllegalAccessException ignored) {
-                // Ignore issues obtaining field
-            }
-        }
-
-        return null;
-    }
-
-    /**
-     * Grab a {@link Field} of an {@link Object}
-     *
-     * @param fieldType the {@link Class} of the object
-     * @param holderType the containing {@code Class}
-     * @return the first matching object or {@code null} if none match
-     */
-    public static @Nullable Field grabFieldByType(Class<?> holderType, Class<?> fieldType) {
-        for (Field field : holderType.getDeclaredFields()) {
-            field.setAccessible(true);
-            if (fieldType.isAssignableFrom(field.getType())) {
-                return field;
-            }
-        }
-
-        if (holderType.getSuperclass() != null) {
-            return grabFieldByType(fieldType, holderType.getSuperclass());
-        }
-
-        return null;
-    }
-
-}

api/src/main/java/com/lishid/openinv/util/StringMetric.java

@@ -1,150 +0,0 @@
-/*
- * Copyright (C) 2011-2021 lishid. All rights reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.util;
-
-public class StringMetric {
-
-    public static float compareJaroWinkler(String a, String b) {
-        final float jaroScore = compareJaro(a, b);
-
-        if (jaroScore < (float) 0.7) {
-            return jaroScore;
-        }
-
-        String prefix = commonPrefix(a, b);
-        int prefixLength = Math.min(prefix.codePointCount(0, prefix.length()), 4);
-
-        return jaroScore + (prefixLength * (float) 0.1 * (1.0f - jaroScore));
-
-    }
-
-    private static float compareJaro(String a, String b) {
-        if (a.isEmpty() && b.isEmpty()) {
-            return 1.0f;
-        }
-
-        if (a.isEmpty() || b.isEmpty()) {
-            return 0.0f;
-        }
-
-        final int[] charsA = a.codePoints().toArray();
-        final int[] charsB = b.codePoints().toArray();
-
-        // Intentional integer division to round down.
-        final int halfLength = Math.max(0, Math.max(charsA.length, charsB.length) / 2 - 1);
-
-        final int[] commonA = getCommonCodePoints(charsA, charsB, halfLength);
-        final int[] commonB = getCommonCodePoints(charsB, charsA, halfLength);
-
-        // commonA and commonB will always contain the same multi-set of
-        // characters. Because getCommonCharacters has been optimized, commonA
-        // and commonB are -1-padded. So in this loop we count transposition
-        // and use commonCharacters to determine the length of the multi-set.
-        float transpositions = 0;
-        int commonCharacters = 0;
-        for (int length = commonA.length; commonCharacters < length
-                && commonA[commonCharacters] > -1; commonCharacters++) {
-            if (commonA[commonCharacters] != commonB[commonCharacters]) {
-                transpositions++;
-            }
-        }
-
-        if (commonCharacters == 0) {
-            return 0.0f;
-        }
-
-        float aCommonRatio = commonCharacters / (float) charsA.length;
-        float bCommonRatio = commonCharacters / (float) charsB.length;
-        float transpositionRatio = (commonCharacters - transpositions / 2.0f) / commonCharacters;
-
-        return (aCommonRatio + bCommonRatio + transpositionRatio) / 3.0f;
-    }
-
-    /*
-     * Returns an array of code points from a within b. A character in b is
-     * counted as common when it is within separation distance from the position
-     * in a.
-     */
-    private static int[] getCommonCodePoints(final int[] charsA, final int[] charsB, final int separation) {
-        final int[] common = new int[Math.min(charsA.length, charsB.length)];
-        final boolean[] matched = new boolean[charsB.length];
-
-        // Iterate of string a and find all characters that occur in b within
-        // the separation distance. Mark any matches found to avoid
-        // duplicate matchings.
-        int commonIndex = 0;
-        for (int i = 0, length = charsA.length; i < length; i++) {
-            final int character = charsA[i];
-            final int index = indexOf(character, charsB, i - separation, i
-                    + separation + 1, matched);
-            if (index > -1) {
-                common[commonIndex++] = character;
-                matched[index] = true;
-            }
-        }
-
-        if (commonIndex < common.length) {
-            common[commonIndex] = -1;
-        }
-
-        // Both invocations will yield the same multi-set terminated by -1, so
-        // they can be compared for transposition without making a copy.
-        return common;
-    }
-
-    /*
-     * Search for code point in buffer starting at fromIndex to toIndex - 1.
-     *
-     * Returns -1 when not found.
-     */
-    private static int indexOf(int character, int[] buffer, int fromIndex, int toIndex, boolean[] matched) {
-
-        // compare char with range of characters to either side
-        for (int j = Math.max(0, fromIndex), length = Math.min(toIndex, buffer.length); j < length; j++) {
-            // check if found
-            if (buffer[j] == character && !matched[j]) {
-                return j;
-            }
-        }
-
-        return -1;
-    }
-
-    private static String commonPrefix(CharSequence a, CharSequence b) {
-        int maxPrefixLength = Math.min(a.length(), b.length());
-
-        int p;
-
-        p = 0;
-        while (p < maxPrefixLength && a.charAt(p) == b.charAt(p)) {
-            ++p;
-        }
-
-        if (validSurrogatePairAt(a, p - 1) || validSurrogatePairAt(b, p - 1)) {
-            --p;
-        }
-
-        return a.subSequence(0, p).toString();
-    }
-
-    private static boolean validSurrogatePairAt(CharSequence string, int index) {
-        return index >= 0 && index <= string.length() - 2 && Character.isHighSurrogate(string.charAt(index)) && Character.isLowSurrogate(string.charAt(index + 1));
-    }
-
-    private StringMetric(){}
-
-}

api/src/main/java/com/lishid/openinv/util/setting/PlayerToggle.java

@@ -0,0 +1,47 @@
+package com.lishid.openinv.util.setting;
+
+import org.bukkit.entity.Player;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.UUID;
+
+/**
+ * A per-player setting that may be enabled or disabled.
+ */
+@NullMarked
+public interface PlayerToggle {
+
+  /**
+   * Get the name of the setting.
+   *
+   * @return the setting name
+   */
+  String getName();
+
+  /**
+   * Get the state of the toggle for a particular player ID.
+   *
+   * @param uuid the player ID
+   * @return true if the setting is enabled
+   */
+  boolean is(UUID uuid);
+
+  /**
+   * Get the state of the toggle for a particular {@link Player},
+   * accounting for permissions required to use the feature.
+   *
+   * @param player the player
+   * @return true if the setting is enabled and the player has the required permissions
+   */
+  boolean is(Player player);
+
+  /**
+   * Set the state of the toggle for a particular player ID.
+   *
+   * @param uuid the player ID
+   * @param enabled whether the setting is enabled
+   * @return true if the setting changed as a result of being set
+   */
+  boolean set(UUID uuid, boolean enabled);
+
+}

api/src/main/java/com/lishid/openinv/util/setting/PlayerToggles.java

@@ -0,0 +1,121 @@
+package com.lishid.openinv.util.setting;
+
+import com.lishid.openinv.util.Permissions;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.UnmodifiableView;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * Utility class containing all of OpenInv's {@link PlayerToggle PlayerToggles}.
+ */
+@NullMarked
+public final class PlayerToggles {
+
+  private static final Map<String, PlayerToggle> TOGGLES = new HashMap<>();
+  private static final PlayerToggle ANY = add(new MemoryToggle("AnyContainer") {
+    @Override
+    public boolean is(Player player) {
+      return is(player.getUniqueId())
+          && (Permissions.CONTAINER_ANY.hasPermission(player) || Permissions.CONTAINER_ANY_USE.hasPermission(player));
+    }
+  });
+  private static final PlayerToggle SILENT = add(new MemoryToggle("SilentContainer") {
+    @Override
+    public boolean is(Player player) {
+      return is(player.getUniqueId())
+          && (Permissions.CONTAINER_SILENT.hasPermission(player) || Permissions.CONTAINER_SILENT_USE.hasPermission(player));
+    }
+  });
+
+  /**
+   * Get the AnyContainer toggle.
+   *
+   * @return the AnyContainer toggle
+   */
+  public static PlayerToggle any() {
+    return ANY;
+  }
+
+  /**
+   * Get the SilentContainer toggle.
+   *
+   * @return the SilentContainer toggle
+   */
+  public static PlayerToggle silent() {
+    return SILENT;
+  }
+
+  /**
+   * Get a toggle by name.
+   *
+   * @param toggleName the name of the toggle
+   * @return the toggle, or null if no such toggle exists.
+   */
+  public static @Nullable PlayerToggle get(String toggleName) {
+    PlayerToggle toggle = TOGGLES.get(toggleName);
+    if (toggle == null) {
+      toggle = TOGGLES.get(toggleName.toLowerCase(Locale.ENGLISH));
+    }
+    return toggle;
+  }
+
+  /**
+   * Get an unmodifable view of all toggles available.
+   *
+   * @return a view of all toggles available
+   */
+  public static @UnmodifiableView Collection<PlayerToggle> get() {
+    return Collections.unmodifiableCollection(TOGGLES.values());
+  }
+
+  private static PlayerToggle add(PlayerToggle toggle) {
+    TOGGLES.put(toggle.getName().toLowerCase(Locale.ENGLISH), toggle);
+    return toggle;
+  }
+
+  private PlayerToggles() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
+  private static abstract class MemoryToggle implements PlayerToggle {
+
+    private final Set<UUID> enabled;
+    private final String name;
+
+    private MemoryToggle(String name) {
+      enabled = new HashSet<>();
+      this.name = name;
+    }
+
+    @Override
+    public String getName() {
+      return this.name;
+    }
+
+    @Override
+    public boolean is(UUID uuid) {
+      return enabled.contains(uuid);
+    }
+
+    @Override
+    public boolean set(UUID uuid, boolean enabled) {
+      if (enabled) {
+        return this.enabled.add(uuid);
+      } else {
+        return this.enabled.remove(uuid);
+      }
+    }
+
+  }
+
+}

assembly/pom.xml

@@ -1,58 +0,0 @@
-<!--
-  ~ Copyright (C) 2011-2022 lishid. All rights reserved.
-  ~
-  ~ This program is free software: you can redistribute it and/or modify
-  ~ it under the terms of the GNU General Public License as published by
-  ~ the Free Software Foundation, version 3.
-  ~
-  ~ This program is distributed in the hope that it will be useful,
-  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
-  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-  ~ GNU General Public License for more details.
-  ~
-  ~ You should have received a copy of the GNU General Public License
-  ~ along with this program. If not, see <http://www.gnu.org/licenses/>.
-  -->
-
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-  <modelVersion>4.0.0</modelVersion>
-
-  <parent>
-    <groupId>com.lishid</groupId>
-    <artifactId>openinvparent</artifactId>
-    <version>4.4.4</version>
-  </parent>
-
-  <artifactId>openinvassembly</artifactId>
-  <name>OpenInvAssembly</name>
-  <packaging>pom</packaging>
-
-  <build>
-    <directory>../target</directory>
-    <finalName>OpenInv</finalName>
-
-    <plugins>
-      <plugin>
-        <artifactId>maven-assembly-plugin</artifactId>
-        <executions>
-          <execution>
-            <id>reactor-uberjar</id>
-            <phase>package</phase>
-            <goals>
-              <goal>single</goal>
-            </goals>
-            <configuration>
-              <appendAssemblyId>false</appendAssemblyId>
-              <descriptors>
-                <descriptor>src/assembly/reactor-uberjar.xml</descriptor>
-              </descriptors>
-            </configuration>
-          </execution>
-        </executions>
-      </plugin>
-    </plugins>
-
-  </build>
-
-</project>

assembly/src/assembly/reactor-uberjar.xml

@@ -1,54 +0,0 @@
-<!--
-  ~ Copyright (C) 2011-2021 lishid. All rights reserved.
-  ~
-  ~ This program is free software: you can redistribute it and/or modify
-  ~ it under the terms of the GNU General Public License as published by
-  ~ the Free Software Foundation, version 3.
-  ~
-  ~ This program is distributed in the hope that it will be useful,
-  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
-  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-  ~ GNU General Public License for more details.
-  ~
-  ~ You should have received a copy of the GNU General Public License
-  ~ along with this program. If not, see <http://www.gnu.org/licenses/>.
-  -->
-
-<assembly xmlns="http://maven.apache.org/ASSEMBLY/2.1.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/ASSEMBLY/2.1.0 http://maven.apache.org/xsd/assembly-2.1.0.xsd">
-
-  <id>reactor-uberjar</id>
-
-  <formats>
-    <format>jar</format>
-  </formats>
-
-  <includeBaseDirectory>false</includeBaseDirectory>
-
-  <moduleSets>
-    <moduleSet>
-
-      <useAllReactorProjects>true</useAllReactorProjects>
-
-      <binaries>
-        <outputDirectory>/</outputDirectory>
-        <unpack>true</unpack>
-        <unpackOptions>
-          <excludes>
-            <!--
-              - Exclude existing meta - assembly will write its own manifest, and the rest is maven
-              - details that end users don't need. Ignoring it saves around 7KB after compression
-              - with a single internal module present.
-             -->
-            <exclude>META-INF/**</exclude>
-          </excludes>
-        </unpackOptions>
-        <!-- Exclude dependencies - shade plugin will handle their inclusion as necessary in individual jars. -->
-        <includeDependencies>false</includeDependencies>
-      </binaries>
-
-    </moduleSet>
-  </moduleSets>
-
-</assembly>

build.gradle.kts

@@ -0,0 +1,47 @@
+plugins {
+  `java-library`
+  alias(libs.plugins.paperweight) apply false
+  alias(libs.plugins.shadow) apply false
+  alias(libs.plugins.errorprone.gradle)
+}
+
+repositories {
+  maven("https://repo.papermc.io/repository/maven-public/")
+}
+
+// Allow submodules to target higher Java release versions.
+java.disableAutoTargetJvm()
+
+subprojects {
+  apply(plugin = "java-library")
+  apply(plugin = rootProject.libs.plugins.errorprone.gradle.get().pluginId)
+
+  repositories {
+    mavenCentral()
+  }
+
+  dependencies {
+    compileOnly(rootProject.libs.jspecify)
+    compileOnly(rootProject.libs.annotations)
+    errorprone(rootProject.libs.errorprone.core)
+  }
+
+  tasks {
+    withType<JavaCompile>().configureEach {
+      options.encoding = Charsets.UTF_8.name()
+    }
+    withType<Javadoc>().configureEach {
+      options.encoding = Charsets.UTF_8.name()
+    }
+  }
+}
+
+// Task to delete ./dist where final files are output.
+tasks.register("cleanDist") {
+  delete("dist")
+}
+
+tasks.clean {
+  // Also delete distribution folder when cleaning.
+  dependsOn(tasks.named("cleanDist"))
+}

buildSrc/build.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+  `kotlin-dsl`
+}
+
+repositories {
+  gradlePluginPortal()
+  mavenCentral()
+}

buildSrc/src/main/kotlin/com/github/jikoo/openinv/BuildToolsValueSource.kt

@@ -0,0 +1,107 @@
+package com.github.jikoo.openinv
+
+import org.gradle.api.file.DirectoryProperty
+import org.gradle.api.provider.Property
+import org.gradle.api.provider.ValueSource
+import org.gradle.api.provider.ValueSourceParameters
+import org.gradle.process.ExecOperations
+import java.io.File
+import java.net.URI
+import java.nio.file.Files
+import javax.inject.Inject
+
+abstract class BuildToolsValueSource : ValueSource<File, BuildToolsValueSource.Parameters> {
+
+  @get:Inject
+  abstract val exec: ExecOperations
+
+  interface Parameters : ValueSourceParameters {
+    val installDir: DirectoryProperty
+    val workingDir: DirectoryProperty
+
+    val spigotVersion: Property<String>
+    val spigotRevision: Property<String>
+
+    val ignoreCached: Property<Boolean>
+
+    val javaHome: DirectoryProperty
+    val javaExecutable: Property<String>
+  }
+
+  override fun obtain(): File {
+    val version = parameters.spigotVersion.get()
+    val revision = parameters.spigotRevision.get()
+    val spigotLocation = parameters.installDir.get().asFile.resolve("spigot-$version.jar")
+    // If Spigot is already installed, don't reinstall.
+    if (!parameters.ignoreCached.get() && spigotLocation.exists()) {
+      println("Skipping Spigot installation, $version is present")
+      return spigotLocation
+    }
+
+    val buildTools = installBuildTools(parameters.workingDir.get().asFile)
+
+    println("Installing Spigot $version (rev $revision)")
+
+    exec.javaexec {
+      environment["JAVA_HOME"] = parameters.javaHome.get()
+      executable = parameters.javaExecutable.get()
+      workingDir = buildTools.parentFile
+      classpath(buildTools)
+      args = listOf("--nogui", "--rev", revision)
+    }.rethrowFailure()
+
+    val spigotBuild = buildTools.parentFile.resolve("Spigot/Spigot-Server/target/spigot-$version.jar")
+
+    if (!spigotBuild.exists()) {
+      throw IllegalStateException(
+        "Spigot build completed, but $spigotBuild does not exist! Did BuildTools change output location?"
+      )
+    }
+
+    spigotBuild.copyTo(spigotLocation, overwrite = true)
+
+    // Mark work for delete.
+    cleanUp(buildTools.parentFile)
+
+    if (!spigotLocation.exists()) {
+      throw IllegalStateException(
+        "Failed to install Spigot $version from $revision. Does the revision point to a different version?"
+      )
+    }
+
+    return spigotLocation
+  }
+
+  private fun installBuildTools(workingDir: File): File {
+    val buildTools = workingDir.resolve("BuildTools.jar")
+    if (buildTools.exists()) {
+      return buildTools
+    }
+
+    workingDir.mkdirs()
+
+    val buildToolsUrl =
+      "https://hub.spigotmc.org/jenkins/job/BuildTools/lastSuccessfulBuild/artifact/target/BuildTools.jar"
+    println("Downloading $buildToolsUrl")
+    val stream = URI.create(buildToolsUrl).toURL().openStream()
+    Files.copy(stream, buildTools.toPath())
+    stream.close()
+
+    return buildTools
+  }
+
+  private fun cleanUp(dir: File) {
+    dir.deleteOnExit()
+    if (!dir.isDirectory) {
+      return
+    }
+
+    dir.listFiles()?.forEach {
+      if (it.isDirectory) {
+        cleanUp(it)
+      } else {
+        it.deleteOnExit()
+      }
+    }
+  }
+}

buildSrc/src/main/kotlin/com/github/jikoo/openinv/SpigotDependencyExtension.kt

@@ -0,0 +1,19 @@
+package com.github.jikoo.openinv
+
+import org.gradle.api.model.ObjectFactory
+import org.gradle.jvm.toolchain.JavaToolchainSpec
+
+abstract class SpigotDependencyExtension(
+  objects: ObjectFactory
+) {
+
+  val version = objects.property(String::class.java)
+  val revision = objects.property(String::class.java)
+    .convention(version.map {
+      it.replace("-R\\d+\\.\\d+-SNAPSHOT".toRegex(), "")
+    })
+  val classifier = objects.property(String::class.java).convention("")
+  val java = objects.property(JavaToolchainSpec::class.java)
+  val ignoreCached = objects.property(Boolean::class.java).convention(false)
+
+}

buildSrc/src/main/kotlin/com/github/jikoo/openinv/SpigotSetup.kt

@@ -0,0 +1,50 @@
+package com.github.jikoo.openinv
+
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.api.plugins.JavaPluginExtension
+import org.gradle.jvm.toolchain.JavaToolchainService
+import java.io.File
+import javax.inject.Inject
+
+abstract class SpigotSetup : Plugin<Project> {
+
+  @get:Inject
+  abstract val javaToolchainService: JavaToolchainService
+
+  override fun apply(target: Project) {
+    target.plugins.apply("java")
+
+    // Set up extension for configuring Spigot dependency.
+    val spigotExt = target.dependencies.extensions.findByType(SpigotDependencyExtension::class.java)
+      ?: target.dependencies.extensions.create(
+        "spigot",
+        SpigotDependencyExtension::class.java,
+        target.objects
+      )
+
+    target.afterEvaluate {
+      // Get Java requirements, defaulting to version used for compilation.
+      spigotExt.java.convention(target.extensions.getByType(JavaPluginExtension::class.java).toolchain)
+      val launcher = javaToolchainService.launcherFor(spigotExt.java.get()).get()
+
+      // Install Spigot with BuildTools.
+      val spigot: File = target.providers.of(BuildToolsValueSource::class.java) {
+        parameters {
+          installDir.set(target.gradle.gradleUserHomeDir.resolve("caches/spigot"))
+          workingDir.set(target.layout.buildDirectory.dir("tmp/buildtools"))
+          spigotVersion.set(spigotExt.version)
+          spigotRevision.set(spigotExt.revision)
+          ignoreCached.set(spigotExt.ignoreCached)
+          javaHome.set(launcher.metadata.installationPath)
+          javaExecutable.set(launcher.executablePath.asFile.path)
+        }
+      }.get()
+
+      // Add Spigot dependency.
+      val dependency = target.dependencies.create(files(spigot))
+      target.dependencies.add("compileOnly", dependency)
+    }
+  }
+
+}

common/build.gradle.kts

@@ -0,0 +1,20 @@
+repositories {
+  maven("https://hub.spigotmc.org/nexus/content/groups/public/")
+}
+
+dependencies {
+  compileOnly(libs.spigotapi)
+}
+
+java {
+  toolchain.languageVersion = JavaLanguageVersion.of(21)
+}
+
+tasks.withType<JavaCompile>().configureEach {
+  options.release = 21
+}
+
+dependencies {
+  implementation(project(":openinvapi"))
+  compileOnly(libs.slf4j.api)
+}

common/src/main/java/com/github/jikoo/openinv/internal/Accessor.java

@@ -0,0 +1,28 @@
+package com.github.jikoo.openinv.internal;
+
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public interface Accessor {
+
+  PlayerManager getPlayerManager();
+
+  IAnySilentContainer getAnySilentContainer();
+
+  ISpecialPlayerInventory createPlayerInventory(Player player);
+
+  ISpecialEnderChest createEnderChest(Player player);
+
+  <T extends ISpecialInventory> @Nullable T get(Inventory bukkitInventory, Class<T> clazz);
+
+  void reload(ConfigurationSection config);
+
+}

common/src/main/java/com/github/jikoo/openinv/internal/PlayerManager.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.github.jikoo.openinv.internal;
+
+import com.lishid.openinv.internal.ISpecialInventory;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryView;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public interface PlayerManager {
+
+  /**
+   * Loads a Player for an OfflinePlayer.
+   * </p>
+   * This method is potentially blocking, and should not be called on the main thread.
+   *
+   * @param offline the OfflinePlayer
+   * @return the Player loaded
+   */
+  @Nullable Player loadPlayer(OfflinePlayer offline);
+
+  /**
+   * Creates a new Player from an existing one that will function slightly better offline.
+   *
+   * @return the Player
+   */
+  Player inject(Player player);
+
+  /**
+   * Opens an ISpecialInventory for a Player.
+   *
+   * @param player the Player opening the ISpecialInventory
+   * @param inventory the Inventory
+   *
+   * @return the InventoryView opened
+   */
+  @Nullable InventoryView openInventory(Player player, ISpecialInventory inventory, boolean viewOnly);
+
+}

common/src/main/java/com/github/jikoo/openinv/internal/container/AnySilentContainerBase.java

@@ -0,0 +1,107 @@
+package com.github.jikoo.openinv.internal.container;
+
+import com.lishid.openinv.internal.IAnySilentContainer;
+import org.bukkit.block.Barrel;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.block.BlockState;
+import org.bukkit.block.EnderChest;
+import org.bukkit.block.ShulkerBox;
+import org.bukkit.block.data.BlockData;
+import org.bukkit.block.data.type.Chest;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryHolder;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public abstract class AnySilentContainerBase implements IAnySilentContainer {
+
+  public enum StateType {
+    ENDER_CHEST,
+    SHULKER_BOX,
+    CHEST,
+    BARREL,
+    OTHER
+  }
+
+  @Override
+  public boolean isAnyContainerNeeded(Block block) {
+    return isAnyContainerNeeded(getStateType(block), block);
+  }
+
+  protected boolean isAnyContainerNeeded(StateType material, Block block) {
+    return switch (material) {
+      // Enderchests require a non-occluding block on top to open.
+      case ENDER_CHEST -> block.getRelative(0, 1, 0).getType().isOccluding();
+      // Shulker boxes require half a block clear in the direction they open.
+      case SHULKER_BOX -> isShulkerBlocked(block);
+      // Chests require that the block above not be occluding or occupied by a cat.
+      case CHEST -> isChestBlocked(block);
+      // Barrels need silent but not any. All others unsupported.
+      default -> false;
+    };
+  }
+
+  @Override
+  public boolean isChestBlocked(Block block) {
+    if (IAnySilentContainer.super.isChestBlocked(block)) {
+      return true;
+    }
+
+    BlockData blockData = block.getBlockData();
+    if (!(blockData instanceof Chest chest) || chest.getType() == Chest.Type.SINGLE) {
+      return false;
+    }
+
+    BlockFace relativeFace = switch (chest.getFacing()) {
+      case NORTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.WEST : BlockFace.EAST;
+      case EAST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.NORTH : BlockFace.SOUTH;
+      case SOUTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.EAST : BlockFace.WEST;
+      case WEST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.SOUTH : BlockFace.NORTH;
+      default -> BlockFace.SELF;
+    };
+    Block relative = block.getRelative(relativeFace);
+
+    if (relative.getType() != block.getType()) {
+      return false;
+    }
+
+    BlockData relativeData = relative.getBlockData();
+    if (!(relativeData instanceof Chest relativeChest)) {
+      return false;
+    }
+
+    if (relativeChest.getFacing() != chest.getFacing()
+        || relativeChest.getType() != (chest.getType() == Chest.Type.RIGHT ? Chest.Type.LEFT : Chest.Type.RIGHT)) {
+      return false;
+    }
+
+    return IAnySilentContainer.super.isChestBlocked(relative);
+  }
+
+  @Override
+  public boolean isAnySilentContainer(Block block) {
+    return isAnySilentContainer(getState(block));
+  }
+
+  @Override
+  public boolean isAnySilentContainer(Inventory inventory) {
+    return isAnySilentContainer(getHolder(inventory));
+  }
+
+  protected StateType getStateType(Block block) {
+    return switch (getState(block)) {
+      case Barrel ignored -> StateType.BARREL;
+      case EnderChest ignored -> StateType.ENDER_CHEST;
+      case ShulkerBox ignored -> StateType.SHULKER_BOX;
+      case org.bukkit.block.Chest ignored -> StateType.CHEST;
+      default -> StateType.OTHER;
+    };
+  }
+
+  protected abstract BlockState getState(Block block);
+
+  protected abstract @Nullable InventoryHolder getHolder(Inventory inventory);
+
+}

common/src/main/java/com/github/jikoo/openinv/internal/container/InternalOwned.java

@@ -0,0 +1,10 @@
+package com.github.jikoo.openinv.internal.container;
+
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public interface InternalOwned<T> {
+
+  T getOwnerHandle();
+
+}

common/src/main/java/com/github/jikoo/openinv/internal/container/ViewOnly.java

@@ -0,0 +1,4 @@
+package com.github.jikoo.openinv.internal.container;
+
+public interface ViewOnly {
+}

common/src/main/java/com/github/jikoo/openinv/internal/container/slot/Content.java

@@ -0,0 +1,66 @@
+package com.github.jikoo.openinv.internal.container.slot;
+
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * An interface defining behaviors for entries in a {@link net.minecraft.world.Container Container}. Used to reduce duplicate content reordering.
+ */
+@NullMarked
+public interface Content<P, I, C, S> {
+
+  /**
+   * Update internal holder.
+   *
+   * @param holder the new holder
+   */
+  void setHolder(P holder);
+
+  /**
+   * Get the current item.
+   *
+   * @return the current item
+   */
+  I get();
+
+  /**
+   * Remove the current item.
+   *
+   * @return the current item
+   */
+  I remove();
+
+  /**
+   * Remove some of the current item.
+   *
+   * @return the current item
+   */
+  I removePartial(int amount);
+
+  /**
+   * Set the current item. If slot is currently not usable, will drop item instead.
+   *
+   * @param itemStack the item to set
+   */
+  void set(I itemStack);
+
+  /**
+   * Get a {@link net.minecraft.world.inventory.Slot Slot} for use in a {@link net.minecraft.world.inventory.AbstractContainerMenu ContainerMenu}. Will
+   * impose any specific restrictions to insertion or removal.
+   *
+   * @param container the backing container
+   * @param slot the slot of the backing container represented
+   * @param x clientside x dimension from top left of inventory, not used
+   * @param y clientside y dimension from top left of inventory, not used
+   * @return a menu slot
+   */
+  S asSlot(C container, int slot, int x, int y);
+
+  /**
+   * Get a loose Bukkit translation of what this slot stores. For example, any slot that drops items at the owner rather
+   * than insert them will report itself as being {@link org.bukkit.event.inventory.InventoryType.SlotType#OUTSIDE}.
+   *
+   * @return the closes Bukkit slot type
+   */
+  org.bukkit.event.inventory.InventoryType.SlotType getSlotType();
+
+}

common/src/main/java/com/github/jikoo/openinv/internal/container/slot/InventoryFactory.java

@@ -0,0 +1,35 @@
+package com.github.jikoo.openinv.internal.container.slot;
+
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.List;
+import java.util.function.Function;
+
+@NullMarked
+public interface InventoryFactory<P, I, C, S, E> {
+
+  Content<P, I, C, S> newCrafting(P holder, int index);
+
+  Content<P, I, C, S> newCraftingResult(P holder);
+
+  Content<P, I, C, S> newCursor(P holder);
+
+  Content<P, I, C, S> newDrop(P holder);
+
+  Content<P, I, C, S> newEquipment(P holder, E equipmentSlot);
+
+  Content<P, I, C, S> newList(P holder, int index, InventoryType.SlotType slotType, Function<P, List<I>> listSupplier);
+
+  Content<P, I, C, S> newOffHand(P holder);
+
+  Content<P, I, C, S> newViewOnly(P holder);
+
+  Content<P, I, C, S> newViewOnly(P holder, I itemStack);
+
+  S wrapViewOnly(S wrapped);
+
+  ItemStack asBukkitMirror(I itemStack);
+
+}

common/src/main/java/com/github/jikoo/openinv/lang/LanguageManager.java

@@ -0,0 +1,309 @@
+package com.github.jikoo.openinv.lang;
+
+import net.md_5.bungee.api.ChatMessageType;
+import net.md_5.bungee.api.chat.TextComponent;
+import org.bukkit.ChatColor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.configuration.Configuration;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.Plugin;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.function.Predicate;
+import java.util.logging.Level;
+
+/**
+ * A simple language manager supporting both custom and bundled languages.
+ */
+@NullMarked
+public class LanguageManager {
+
+  private final Plugin plugin;
+  private final File folder;
+  private final String defaultLocale;
+  private final Map<String, YamlConfiguration> locales;
+
+  public LanguageManager(Plugin plugin, String defaultLocale) {
+    this.plugin = plugin;
+    this.defaultLocale = defaultLocale;
+    this.locales = new HashMap<>();
+    this.folder = new File(plugin.getDataFolder(), "locale");
+
+    if (!folder.exists() && !folder.mkdirs()) {
+      plugin.getLogger().warning(() -> "Unable to create " + folder.getPath() + "! Languages may not be editable.");
+    }
+
+    reload();
+  }
+
+  public void reload() {
+    this.locales.clear();
+    getOrLoadLocale(defaultLocale);
+  }
+
+  private YamlConfiguration getOrLoadLocale(String locale) {
+    YamlConfiguration loaded = locales.get(locale);
+    if (loaded != null) {
+      return loaded;
+    }
+
+    LangLocation lang = bestMatch(locale, null);
+
+    // If a parent was a better match, check if it is already loaded.
+    if (!locale.equals(lang.locale)) {
+      loaded = locales.get(lang.locale);
+      if (loaded != null) {
+        locales.put(locale, loaded);
+        return loaded;
+      }
+    }
+
+    // Load locale config from disk and bundled locale defaults.
+    YamlConfiguration localeConfig = loadLocale(lang);
+
+    // If the locale is not the default locale, also handle any missing translations from the default locale.
+    if (!locale.equals(defaultLocale)) {
+      addTranslationFallthrough(lang, localeConfig);
+
+      if (plugin.getConfig().getBoolean("settings.secret.warn-about-guess-section", true)
+          && localeConfig.isConfigurationSection("guess")) {
+        // Warn that guess section exists. This should run once per language per server restart
+        // when accessed by a user to hint to server owners that they can make UX improvements.
+        plugin.getLogger().info(() -> "[LanguageManager] Missing translations from " + lang.locale + ".yml! Check the guess section!");
+      }
+    }
+
+    locales.put(locale, localeConfig);
+    locales.put(lang.locale, localeConfig);
+
+    return localeConfig;
+  }
+
+  private LangLocation bestMatch(String locale, @Nullable LangLocation initial) {
+    File file = new File(folder, locale + ".yml");
+    InputStream bundled = plugin.getResource("locale/" + locale + ".yml");
+
+    if (file.exists() || bundled != null) {
+      return new LangLocation(locale, file, bundled);
+    }
+
+    if (initial == null) {
+      initial = new LangLocation(locale, file, null);
+    }
+
+    int lastSeparator = locale.lastIndexOf('_');
+
+    // Must be at least some content before separator.
+    if (lastSeparator < 1) {
+      return initial;
+    }
+
+    return bestMatch(locale.substring(0, lastSeparator), initial);
+  }
+
+  private YamlConfiguration loadLocale(LangLocation lang) {
+    YamlConfiguration localeConfigDefaults;
+    if (lang.bundled == null) {
+      localeConfigDefaults = new YamlConfiguration();
+    } else {
+      try (BufferedReader reader = new BufferedReader(new InputStreamReader(lang.bundled, StandardCharsets.UTF_8))) {
+        localeConfigDefaults = YamlConfiguration.loadConfiguration(reader);
+      } catch (IOException e) {
+        plugin.getLogger().log(Level.WARNING, e, () -> "[LanguageManager] Unable to load resource " + lang.locale + ".yml");
+        localeConfigDefaults = new YamlConfiguration();
+      }
+    }
+
+    if (!lang.file.exists()) {
+      // If the file does not exist on disk, save bundled defaults.
+      try {
+        localeConfigDefaults.save(lang.file);
+      } catch (IOException e) {
+        plugin.getLogger().log(Level.WARNING, e, () -> "[LanguageManager] Unable to save resource " + lang.locale + ".yml");
+      }
+      // Return loaded bundled locale.
+      return localeConfigDefaults;
+    }
+
+    // If the file does exist on disk, load it.
+    YamlConfiguration localeConfig = YamlConfiguration.loadConfiguration(lang.file);
+    // Check for missing translations from the bundled file.
+    List<String> newKeys = getMissingKeys(localeConfigDefaults, localeConfig::isSet);
+
+    if (newKeys.isEmpty()) {
+      return localeConfig;
+    }
+
+    // Get guess section for missing keys.
+    ConfigurationSection guess = localeConfig.getConfigurationSection("guess");
+
+    for (String newKey : newKeys) {
+      // Set all missing keys to defaults.
+      localeConfig.set(newKey, localeConfigDefaults.get(newKey));
+
+      // Delete relevant guess keys in case this is a new translation.
+      if (guess != null) {
+        guess.set(newKey, null);
+      }
+    }
+
+    // If guess section is empty, delete it.
+    if (guess != null && guess.getKeys(false).isEmpty()) {
+      localeConfig.set("guess", null);
+    }
+
+    plugin.getLogger().info(() -> "[LanguageManager] Added new translation keys to " + lang.locale + ".yml: " + String.join(", ", newKeys));
+
+    // Write new keys to disk.
+    try {
+      localeConfig.save(lang.file);
+    } catch (IOException e) {
+      plugin.getLogger().log(Level.WARNING, e, () -> "[LanguageManager] Unable to save resource " + lang.locale + ".yml");
+    }
+
+    return localeConfig;
+  }
+
+  private void addTranslationFallthrough(LangLocation location, YamlConfiguration localeConfig) {
+    YamlConfiguration defaultLocaleConfig = locales.get(defaultLocale);
+
+    // Get missing keys. Keys that already have a guess value are not new and don't need to trigger another write.
+    List<String> missingKeys = getMissingKeys(
+        defaultLocaleConfig,
+        key -> localeConfig.isSet(key) || localeConfig.isSet("guess." + key)
+    );
+
+    if (!missingKeys.isEmpty()) {
+      // Set up guess section for missing keys.
+      for (String key : missingKeys) {
+        localeConfig.set("guess." + key, defaultLocaleConfig.get(key));
+      }
+
+      // Write modified guess section to disk.
+      try {
+        localeConfig.save(location.file);
+      } catch (IOException e) {
+        plugin.getLogger().log(Level.WARNING, e, () -> "[LanguageManager] Unable to save resource " + location.locale + ".yml");
+      }
+    }
+
+    // Fall through to default locale.
+    localeConfig.setDefaults(defaultLocaleConfig);
+  }
+
+  private List<String> getMissingKeys(
+      Configuration configurationDefault,
+      Predicate<String> nodeSetPredicate
+  ) {
+    List<String> missingKeys = new ArrayList<>();
+    for (String key : configurationDefault.getKeys(true)) {
+      if (!configurationDefault.isConfigurationSection(key) && !nodeSetPredicate.test(key)) {
+        // Missing keys are non-section keys that fail the predicate.
+        missingKeys.add(key);
+      }
+    }
+    return missingKeys;
+  }
+
+  public @Nullable String getValue(String key, @Nullable String locale) {
+    String value = getOrLoadLocale(locale == null ? defaultLocale : locale.toLowerCase(Locale.ENGLISH)).getString(key);
+    if (value == null || value.isBlank()) {
+      return null;
+    }
+
+    value = ChatColor.translateAlternateColorCodes('&', value);
+
+    return value;
+  }
+
+  public @Nullable String getValue(
+      String key,
+      @Nullable String locale,
+      Replacement... replacements
+  ) {
+    String value = getValue(key, locale);
+
+    if (value == null) {
+      return null;
+    }
+
+    for (Replacement replacement : replacements) {
+      value = value.replace(replacement.placeholder(), replacement.value());
+    }
+
+    return value;
+  }
+
+  public @Nullable String getLocalizedMessage(CommandSender sender, String key) {
+    return getValue(key, getLocale(sender));
+  }
+
+  public @Nullable String getLocalizedMessage(
+      CommandSender sender,
+      String key,
+      Replacement... replacements
+  ) {
+    return getValue(key, getLocale(sender), replacements);
+  }
+
+  private String getLocale(CommandSender sender) {
+    if (sender instanceof Player player) {
+      return player.getLocale();
+    } else {
+      return plugin.getConfig().getString("settings.locale", "en");
+    }
+  }
+
+  public void sendMessage(CommandSender sender, String key) {
+    String message = getLocalizedMessage(sender, key);
+
+    if (message != null && !message.isEmpty()) {
+      sender.sendMessage(message);
+    }
+  }
+
+  public void sendMessage(CommandSender sender, String key, Replacement... replacements) {
+    String message = getLocalizedMessage(sender, key, replacements);
+
+    if (message != null && !message.isEmpty()) {
+      sender.sendMessage(message);
+    }
+  }
+
+  public void sendSystemMessage(Player player, String key) {
+    String message = getLocalizedMessage(player, key);
+
+    if (message == null) {
+      return;
+    }
+
+    int newline = message.indexOf('\n');
+    if (newline != -1) {
+      // No newlines in action bar chat.
+      message = message.substring(0, newline);
+    }
+
+    if (message.isEmpty()) {
+      return;
+    }
+
+    player.spigot().sendMessage(ChatMessageType.ACTION_BAR, TextComponent.fromLegacy(message));
+  }
+
+  private record LangLocation(String locale, File file, @Nullable InputStream bundled) {}
+
+}

common/src/main/java/com/github/jikoo/openinv/lang/Replacement.java

@@ -0,0 +1,14 @@
+package com.github.jikoo.openinv.lang;
+
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * A data holder for string replacement in translations.
+ *
+ * @param placeholder the placeholder to be replaced
+ * @param value the value to insert
+ */
+@NullMarked
+public record Replacement(String placeholder, String value) {
+
+}

common/src/main/java/com/github/jikoo/openinv/util/JulLoggerAdapter.java

@@ -0,0 +1,131 @@
+package com.github.jikoo.openinv.util;
+
+import org.jspecify.annotations.NullMarked;
+import org.slf4j.Marker;
+import org.slf4j.helpers.LegacyAbstractLogger;
+import org.slf4j.helpers.MessageFormatter;
+import org.slf4j.helpers.NormalizedParameters;
+import org.slf4j.spi.LocationAwareLogger;
+
+import java.util.logging.Level;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+
+/**
+ * An adapter for wrapping a {@link java.util.logging.Logger} as a {@link org.slf4j.Logger}.
+ * <br>Largely based on {@code JDK14LoggerAdapter}, which is not present at runtime.
+ */
+@NullMarked
+public class JulLoggerAdapter extends LegacyAbstractLogger implements LocationAwareLogger {
+
+  private final Logger wrapped;
+
+  public JulLoggerAdapter(Logger wrapped) {
+    this.wrapped = wrapped;
+    this.name = wrapped.getName();
+  }
+
+  @Override
+  protected String getFullyQualifiedCallerName() {
+    return JulLoggerAdapter.class.getName();
+  }
+
+  @Override
+  protected void handleNormalizedLoggingCall(
+      org.slf4j.event.Level slf4jLevel,
+      Marker marker,
+      String msg,
+      Object[] args,
+      Throwable thrown
+  ) {
+    Level level = fromSlf4jLevel(slf4jLevel);
+
+    if (wrapped.isLoggable(level)) {
+      normalizedLog(getFullyQualifiedCallerName(), level, msg, args, thrown);
+    }
+  }
+
+  private void normalizedLog(String fqcn, Level level, String msg, Object[] args, Throwable thrown) {
+    String formatted = MessageFormatter.basicArrayFormat(msg, args);
+    LogRecord logRecord = new LogRecord(level, formatted);
+    logRecord.setLoggerName(getName());
+    logRecord.setThrown(thrown);
+
+    addSource(fqcn, logRecord);
+
+    wrapped.log(logRecord);
+  }
+
+  private void addSource(String fqcn, LogRecord logRecord) {
+    StackWalker.getInstance().walk(stream -> stream
+        // Start at index 2 - this is an internal method, so we want at least the caller's caller.
+        .skip(2)
+        // Walk at maximum 10 frames.
+        .limit(10)
+        .filter(frame -> isIgnored(frame.getClassName(), fqcn))
+        .findFirst()
+    ).ifPresent(frame -> {
+      logRecord.setSourceClassName(frame.getClassName());
+      logRecord.setSourceMethodName(frame.getMethodName());
+    });
+  }
+
+  private boolean isIgnored(String className, String fqcn) {
+    if (className.equals(fqcn)) {
+      return true;
+    }
+    // Ignore slf4j classes - they shouldn't be the source.
+    if (className.startsWith("org.slf4j.")) {
+      return true;
+    }
+    return className.equals(getFullyQualifiedCallerName());
+  }
+
+  @Override
+  public void log(Marker marker, String callerFqn, int levelInt, String msg, Object[] args, Throwable thrown) {
+    Level level = fromSlf4jLevel(org.slf4j.event.Level.intToLevel(levelInt));
+
+    if (!wrapped.isLoggable(level)) {
+      return;
+    }
+
+    NormalizedParameters params = NormalizedParameters.normalize(msg, args, thrown);
+    normalizedLog(callerFqn, level, params.getMessage(), params.getArguments(), params.getThrowable());
+  }
+
+  private Level fromSlf4jLevel(org.slf4j.event.Level level) {
+    return switch (level) {
+      case TRACE -> Level.FINEST;
+      case DEBUG -> Level.FINE;
+      case INFO -> Level.INFO;
+      case WARN -> Level.WARNING;
+      case ERROR -> Level.SEVERE;
+    };
+  }
+
+  @Override
+  public boolean isTraceEnabled() {
+    return wrapped.isLoggable(Level.FINEST);
+  }
+
+  @Override
+  public boolean isDebugEnabled() {
+    return wrapped.isLoggable(Level.FINE);
+  }
+
+  @Override
+  public boolean isInfoEnabled() {
+    return wrapped.isLoggable(Level.INFO);
+  }
+
+  @Override
+  public boolean isWarnEnabled() {
+    return wrapped.isLoggable(Level.WARNING);
+  }
+
+  @Override
+  public boolean isErrorEnabled() {
+    return wrapped.isLoggable(Level.SEVERE);
+  }
+
+}

common/src/main/java/com/github/jikoo/openinv/util/ReflectionHelper.java

@@ -0,0 +1,64 @@
+package com.github.jikoo.openinv.util;
+
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.lang.reflect.Field;
+
+/**
+ * A utility for making reflection easier.
+ */
+@NullMarked
+public final class ReflectionHelper {
+
+  /**
+   * Grab an {@link Object} stored in a {@link Field} of another {@code Object}.
+   *
+   * <p>This casts the field to the correct class. Any issues will result in a {@code null} return value.
+   *
+   * @param fieldType the {@link Class} of {@code Object} stored in the {@code Field}
+   * @param holder the containing {@code Object}
+   * @param <T> the type of stored {@code Object}
+   * @return the first matching {@code Object} or {@code null} if none match
+   */
+  public static <T> @Nullable T grabObjectByType(final Object holder, final Class<T> fieldType) {
+    Field field = grabFieldByType(holder.getClass(), fieldType);
+
+    if (field != null) {
+      try {
+        return fieldType.cast(field.get(holder));
+      } catch (IllegalAccessException ignored) {
+        // Ignore issues obtaining field
+      }
+    }
+
+    return null;
+  }
+
+  /**
+   * Grab a {@link Field} of an {@link Object}
+   *
+   * @param fieldType the {@link Class} of the object
+   * @param holderType the containing {@code Class}
+   * @return the first matching object or {@code null} if none match
+   */
+  public static @Nullable Field grabFieldByType(Class<?> holderType, Class<?> fieldType) {
+    for (Field field : holderType.getDeclaredFields()) {
+      if (fieldType.isAssignableFrom(field.getType())) {
+        field.setAccessible(true);
+        return field;
+      }
+    }
+
+    if (holderType.getSuperclass() != null) {
+      return grabFieldByType(fieldType, holderType.getSuperclass());
+    }
+
+    return null;
+  }
+
+  private ReflectionHelper() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
+}

common/src/main/java/com/lishid/openinv/event/OpenEvents.java

@@ -0,0 +1,40 @@
+package com.lishid.openinv.event;
+
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.util.setting.PlayerToggle;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.Event;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.UUID;
+
+/**
+ * Construct and call events.
+ */
+@NullMarked
+public final class OpenEvents {
+
+  public static boolean saveCancelled(Player player) {
+    return call(new PlayerSaveEvent(player));
+  }
+
+  public static boolean saveCancelled(ISpecialInventory inventory) {
+    return call(new OpenPlayerSaveEvent((Player) inventory.getPlayer(), inventory));
+  }
+
+  public static void notifyPlayerToggle(PlayerToggle toggle, UUID uuid, boolean state) {
+    Bukkit.getPluginManager().callEvent(new PlayerToggledEvent(toggle, uuid, state));
+  }
+
+  private static <T extends Event & Cancellable> boolean call(T event) {
+    Bukkit.getPluginManager().callEvent(event);
+    return event.isCancelled();
+  }
+
+  private OpenEvents() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
+}

gradle.properties

@@ -0,0 +1,9 @@
+# Project meta
+group=com.lishid.openinv
+version=5.3.6-SNAPSHOT
+description=A Bukkit plugin for opening normally-inaccessible inventories.
+
+# Gradle configuration
+org.gradle.parallel=true
+org.gradle.caching=true
+org.gradle.configuration-cache=true

gradle/libs.versions.toml

@@ -0,0 +1,33 @@
+[versions]
+spigotapi = "1.21.3-R0.1-SNAPSHOT"
+planarwrappers = "3.3.0"
+jspecify = "1.0.1"
+annotations = "26.1.0"
+paperweight = "2.0.0-beta.24"
+shadow = "9.6.1"
+folia-scheduler-wrapper = "v0.0.3"
+errorprone-core = "2.51.0"
+errorprone-gradle = "5.1.1"
+slf4j = "2.0.20"
+sqlite-jdbc = "3.49.1.0"
+mockito-core = "5.24.0"
+junit-jupiter = "6.1.3"
+hamcrest = "3.0"
+
+[libraries]
+spigotapi = { module = "org.spigotmc:spigot-api", version.ref = "spigotapi" }
+planarwrappers = { module = "com.github.jikoo:planarwrappers", version.ref = "planarwrappers" }
+jspecify = { module = "org.jspecify:jspecify", version.ref = "jspecify" }
+annotations = { module = "org.jetbrains:annotations", version.ref = "annotations" }
+folia-scheduler-wrapper = { module = "com.github.NahuLD.folia-scheduler-wrapper:folia-scheduler-wrapper", version.ref = "folia-scheduler-wrapper" }
+errorprone-core = { module = "com.google.errorprone:error_prone_core", version.ref = "errorprone-core" }
+slf4j-api = { module = "org.slf4j:slf4j-api", version.ref = "slf4j" }
+sqlite-jdbc = { module = "org.xerial:sqlite-jdbc", version.ref = "sqlite-jdbc" }
+mockito-core = { module = "org.mockito:mockito-core", version.ref = "mockito-core" }
+junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit-jupiter" }
+hamcrest = { module = "org.hamcrest:hamcrest", version.ref = "hamcrest" }
+
+[plugins]
+paperweight = { id = "io.papermc.paperweight.userdev", version.ref = "paperweight" }
+shadow = { id = "com.gradleup.shadow", version.ref = "shadow" }
+errorprone-gradle = { id = "net.ltgt.errorprone", version.ref = "errorprone-gradle" }

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,9 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.8.2-bin.zip
+networkTimeout=10000
+retries=0
+retryBackOffMs=500
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   gradlew start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh gradlew
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/3d91ce3b8caaf77ad09f381f43615b715b53f72c/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,112 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  gradlew startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables, and ensure extensions are enabled
+setlocal EnableExtensions
+
+@rem Catch executions from older scripts and ensure they exit cleanly.
+@rem This can be removed once we can be reasonably confident that few people
+@rem will be migrating directly to this new wrapper.
+goto afterSafetyNet
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+goto exitWithErrorLevel
+:afterSafetyNet
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+1>&2 echo.
+1>&2 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+1>&2 echo.
+1>&2 echo Please set the JAVA_HOME variable in your environment to match the
+1>&2 echo location of your Java installation.
+
+"%COMSPEC%" /c exit 1
+goto exitWithErrorLevel
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+1>&2 echo.
+1>&2 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+1>&2 echo.
+1>&2 echo Please set the JAVA_HOME variable in your environment to match the
+1>&2 echo location of your Java installation.
+
+"%COMSPEC%" /c exit 1
+goto exitWithErrorLevel
+
+:execute
+@rem Setup the command line
+
+
+
+@rem Execute gradlew
+@rem endlocal doesn't take effect until after the line is parsed and variables are expanded
+@rem which allows us to clear the local environment before executing the java command
+endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel & goto exitWithErrorLevel
+
+@rem This label must not be changed. We rely on old scripts being able to jump to this point.
+:exitWithErrorLevel
+@rem Use "%COMSPEC%" /c exit to allow operators to work properly in scripts
+"%COMSPEC%" /c exit %ERRORLEVEL%

internal/paper1_21_11/build.gradle.kts

@@ -0,0 +1,25 @@
+plugins {
+  alias(libs.plugins.paperweight)
+}
+
+java {
+  toolchain.languageVersion = JavaLanguageVersion.of(21)
+}
+
+tasks.withType<JavaCompile>().configureEach {
+  options.release = 21
+}
+
+dependencies {
+  implementation(project(":openinvapi")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+  implementation(project(":openinvcommon")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+  implementation(project(":openinvadapterpaper26_1")) {
+    exclude(group = "io.papermc.paper", module = "dev-bundle")
+  }
+
+  paperweight.paperDevBundle("1.21.11-R0.1-SNAPSHOT")
+}

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/InternalAccessor.java

@@ -0,0 +1,30 @@
+package com.lishid.openinv.internal.paper1_21_11;
+
+import com.github.jikoo.openinv.lang.LanguageManager;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.internal.paper1_21_11.container.OpenEnderChest;
+import com.lishid.openinv.internal.paper1_21_11.container.OpenInventory;
+import org.bukkit.entity.Player;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.logging.Logger;
+
+@NullMarked
+public class InternalAccessor extends com.lishid.openinv.internal.paper26_1.InternalAccessor {
+
+  public InternalAccessor(Logger logger, LanguageManager lang) {
+    super(logger, lang);
+  }
+
+  @Override
+  public ISpecialEnderChest createEnderChest(Player player) {
+    return new OpenEnderChest(player);
+  }
+
+  @Override
+  public ISpecialPlayerInventory createPlayerInventory(Player player) {
+    return new OpenInventory(factory, player);
+  }
+
+}

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/container/OpenEnderChest.java

@@ -0,0 +1,35 @@
+package com.lishid.openinv.internal.paper1_21_11.container;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper1_21_11.container.menu.OpenEnderChestMenu;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenEnderChest extends com.lishid.openinv.internal.paper26_3.container.OpenEnderChest {
+
+  public OpenEnderChest(org.bukkit.entity.Player player) {
+    super(player);
+  }
+
+  @Override
+  public @Nullable OpenChestMenu<?> createMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      Player player,
+      int i,
+      boolean viewOnly
+  ) {
+    if (player instanceof ServerPlayer serverPlayer) {
+      return new OpenEnderChestMenu(factory, this, serverPlayer, i, viewOnly);
+    }
+    return null;
+  }
+
+}

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/container/OpenInventory.java

@@ -0,0 +1,33 @@
+package com.lishid.openinv.internal.paper1_21_11.container;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper1_21_11.container.menu.OpenInventoryMenu;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenInventory extends com.lishid.openinv.internal.paper26_3.container.OpenInventory {
+
+  public OpenInventory(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      org.bukkit.entity.Player bukkitPlayer
+  ) {
+    super(factory, bukkitPlayer);
+  }
+
+  @Override
+  public @Nullable OpenChestMenu<?> createMenu(Player player, int i, boolean viewOnly) {
+    if (player instanceof ServerPlayer serverPlayer) {
+      return new OpenInventoryMenu(factory, this, serverPlayer, i, viewOnly);
+    }
+    return null;
+  }
+
+}

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/container/menu/OpenEnderChestMenu.java

@@ -0,0 +1,72 @@
+package com.lishid.openinv.internal.paper1_21_11.container.menu;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.OpenEnderChest;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenSyncMenu;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.ClickType;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenEnderChestMenu extends OpenSyncMenu<OpenEnderChest> {
+
+  public OpenEnderChestMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      OpenEnderChest enderChest,
+      ServerPlayer viewer,
+      int containerId,
+      boolean viewOnly
+  ) {
+    super(getChestMenuType(enderChest.getContainerSize()), containerId, factory, enderChest, viewer, viewOnly);
+  }
+
+  @Override
+  public ItemStack quickMoveStack(Player player, int index) {
+    if (viewOnly) {
+      return ItemStack.EMPTY;
+    }
+
+    // See ChestMenu
+    Slot slot = this.slots.get(index);
+
+    if (slot.isFake() || !slot.hasItem()) {
+      return ItemStack.EMPTY;
+    }
+
+    ItemStack itemStack = slot.getItem();
+    ItemStack original = itemStack.copy();
+
+    if (index < topSize) {
+      if (!this.moveItemStackTo(itemStack, topSize, this.slots.size(), true)) {
+        return ItemStack.EMPTY;
+      }
+    } else if (!this.moveItemStackTo(itemStack, 0, topSize, false)) {
+      return ItemStack.EMPTY;
+    }
+
+    if (itemStack.isEmpty()) {
+      slot.setByPlayer(ItemStack.EMPTY);
+    } else {
+      slot.setChanged();
+    }
+
+    return original;
+  }
+
+  @Override
+  public void clicked(int i, int j, ClickType clickType, Player player) {
+    if (viewOnly) {
+      if (clickType == ClickType.QUICK_CRAFT) {
+        sendAllDataToRemote();
+      }
+      return;
+    }
+    super.clicked(i, j, clickType, player);
+  }
+
+}

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/container/menu/OpenInventoryMenu.java

@@ -0,0 +1,39 @@
+package com.lishid.openinv.internal.paper1_21_11.container.menu;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import com.lishid.openinv.internal.paper26_3.container.menu.BaseOpenInventoryMenu;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.ClickType;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenInventoryMenu extends BaseOpenInventoryMenu {
+
+  public OpenInventoryMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      BaseOpenInventory inventory,
+      ServerPlayer viewer,
+      int i,
+      boolean viewOnly
+  ) {
+    super(factory, inventory, viewer, i, viewOnly);
+  }
+
+  @Override
+  public void clicked(int i, int j, ClickType clickType, Player player) {
+    if (viewOnly) {
+      if (clickType == ClickType.QUICK_CRAFT) {
+        sendAllDataToRemote();
+      }
+      return;
+    }
+    super.clicked(i, j, clickType, player);
+  }
+
+}

internal/paper26_1/build.gradle.kts

@@ -0,0 +1,45 @@
+plugins {
+  alias(libs.plugins.paperweight)
+}
+
+repositories {
+  maven("https://repo.papermc.io/repository/maven-public/")
+}
+
+// Paper is compiled with Java 25, so we have to use a Java 25 toolchain.
+java {
+  toolchain.languageVersion.set(JavaLanguageVersion.of(25))
+}
+
+// To minimize duplicate code, the adapter for 1.21.11 is built off of this module, so we need to target Java 21.
+tasks.withType<JavaCompile>().configureEach {
+  options.release = 21
+}
+
+// As a result, we have to specifically tell Gradle it's okay if our dependencies require Java 25,
+// because secretly sometimes they don't!
+configurations.matching { it.isCanBeResolved && it.name.endsWith("Classpath") }.all {
+  attributes {
+    attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 25)
+  }
+}
+
+dependencies {
+  implementation(project(":openinvapi")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+  implementation(project(":openinvcommon")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+  api(project(":openinvadapterpaper26_2")) {
+    exclude(group = "io.papermc.paper", module = "dev-bundle")
+  }
+
+  paperweight.paperDevBundle("26.1.2.build.+")
+}
+
+tasks.reobfJar {
+  enabled = false
+}
+
+configurations.reobf.get().outgoing.artifacts.clear()

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/InternalAccessor.java

@@ -0,0 +1,53 @@
+package com.lishid.openinv.internal.paper26_1;
+
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_1.container.AnySilentContainer;
+import com.lishid.openinv.internal.paper26_1.container.OpenEnderChest;
+import com.lishid.openinv.internal.paper26_1.player.PlayerManager;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.PlaceholderLoader;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.entity.Player;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.logging.Logger;
+
+@NullMarked
+public class InternalAccessor extends com.lishid.openinv.internal.paper26_2.InternalAccessor {
+
+  public InternalAccessor(Logger logger, LanguageManager lang) {
+    super(logger, lang);
+  }
+
+  @Override
+  protected PlayerManager createPlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
+    return new PlayerManager(logger, factory);
+  }
+
+  @Override
+  protected AnySilentContainer createAnySilentContainer(
+      Logger logger,
+      LanguageManager lang
+  ) {
+    return new AnySilentContainer(logger, lang);
+  }
+
+  @Override
+  protected PlaceholderLoader createPlaceholderLoader() {
+    return new com.lishid.openinv.internal.paper26_1.container.slot.placeholder.PlaceholderLoader();
+  }
+
+  @Override
+  public ISpecialEnderChest createEnderChest(Player player) {
+    return new OpenEnderChest(player);
+  }
+
+}

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/container/AnySilentContainer.java

@@ -0,0 +1,21 @@
+package com.lishid.openinv.internal.paper26_1.container;
+
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.world.level.block.entity.RandomizableContainerBlockEntity;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.logging.Logger;
+
+@NullMarked
+public class AnySilentContainer extends com.lishid.openinv.internal.paper26_3.container.AnySilentContainer {
+
+  public AnySilentContainer(Logger logger, LanguageManager lang) {
+    super(logger, lang);
+  }
+
+  @Override
+  protected boolean hasLootTable(RandomizableContainerBlockEntity lootable) {
+    return lootable.lootTable != null;
+  }
+
+}

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/container/OpenEnderChest.java

@@ -0,0 +1,20 @@
+package com.lishid.openinv.internal.paper26_1.container;
+
+import net.minecraft.core.NonNullList;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenEnderChest extends com.lishid.openinv.internal.paper26_3.container.OpenEnderChest {
+
+  public OpenEnderChest(org.bukkit.entity.Player player) {
+    super(player);
+  }
+
+  @Override
+  protected NonNullList<ItemStack> getEnderChestItems(ServerPlayer owner) {
+    return owner.getEnderChestInventory().items;
+  }
+
+}

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/container/slot/placeholder/PlaceholderLoader.java

@@ -0,0 +1,20 @@
+package com.lishid.openinv.internal.paper26_1.container.slot.placeholder;
+
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.Items;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class PlaceholderLoader extends com.lishid.openinv.internal.paper26_3.container.slot.placeholder.PlaceholderLoader {
+
+  @Override
+  protected Item getDefaultCursorItem() {
+    return Items.WHITE_BANNER;
+  }
+
+  @Override
+  protected Item getDefaultNotSlotItem() {
+    return Items.WHITE_STAINED_GLASS_PANE;
+  }
+
+}

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/player/PlayerManager.java

@@ -0,0 +1,50 @@
+package com.lishid.openinv.internal.paper26_1.player;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.storage.LevelData;
+import net.minecraft.world.phys.Vec3;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.logging.Logger;
+
+@NullMarked
+public class PlayerManager extends com.lishid.openinv.internal.paper26_3.player.PlayerManager {
+
+  public PlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
+    super(logger, factory);
+  }
+
+  @Override
+  protected void removeAdvancementListeners(ServerPlayer entity) {
+    entity.getAdvancements().stopListening();
+  }
+
+  @Override
+  protected LevelData.RespawnData getRespawnData(ServerLevel level) {
+    return level.levelData.getRespawnData();
+  }
+
+  @Override
+  protected Vec3 getAdjustedSpawnLocation(
+      ServerPlayer player,
+      ServerLevel level,
+      LevelData.RespawnData respawnData
+  ) {
+    return player.adjustSpawnLocation(level, respawnData.pos()).getBottomCenter();
+  }
+
+  @Override
+  protected void setServerLevel(ServerPlayer player, ServerLevel level) {
+    player.spawnIn(level);
+  }
+
+}

internal/paper26_2/build.gradle.kts

@@ -0,0 +1,45 @@
+plugins {
+  alias(libs.plugins.paperweight)
+}
+
+repositories {
+  maven("https://repo.papermc.io/repository/maven-public/")
+}
+
+// Paper is compiled with Java 25, so we have to use a Java 25 toolchain.
+java {
+  toolchain.languageVersion.set(JavaLanguageVersion.of(25))
+}
+
+// To minimize duplicate code, the adapter for 1.21.11 is built off of this module, so we need to target Java 21.
+tasks.withType<JavaCompile>().configureEach {
+  options.release = 21
+}
+
+// As a result, we have to specifically tell Gradle it's okay if our dependencies require Java 25,
+// because secretly sometimes they don't!
+configurations.matching { it.isCanBeResolved && it.name.endsWith("Classpath") }.all {
+  attributes {
+    attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 25)
+  }
+}
+
+dependencies {
+  implementation(project(":openinvapi")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+  implementation(project(":openinvcommon")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+  api(project(":openinvadapterpaper26_3")) {
+    exclude(group = "io.papermc.paper", module = "dev-bundle")
+  }
+
+  paperweight.paperDevBundle("26.2.build.+")
+}
+
+tasks.reobfJar {
+  enabled = false
+}
+
+configurations.reobf.get().outgoing.artifacts.clear()

internal/paper26_2/src/main/java/com/lishid/openinv/internal/paper26_2/InternalAccessor.java

@@ -0,0 +1,27 @@
+package com.lishid.openinv.internal.paper26_2;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_2.container.slot.OpenInventoryFactory;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.logging.Logger;
+
+@NullMarked
+public class InternalAccessor extends com.lishid.openinv.internal.paper26_3.InternalAccessor {
+
+  public InternalAccessor(Logger logger, LanguageManager lang) {
+    super(logger, lang);
+  }
+
+  @Override
+  protected InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> createInventoryFactory() {
+    return new OpenInventoryFactory();
+  }
+
+}

internal/paper26_2/src/main/java/com/lishid/openinv/internal/paper26_2/container/slot/OpenInventoryFactory.java

@@ -0,0 +1,95 @@
+package com.lishid.openinv.internal.paper26_2.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentCrafting;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentCursor;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentDrop;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentViewOnly;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotViewOnly;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenInventoryFactory extends com.lishid.openinv.internal.paper26_3.container.slot.OpenInventoryFactory {
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCrafting(
+      ServerPlayer holder,
+      int index
+  ) {
+    return new ContentCrafting(holder, index) {
+      @Override
+      public void set(ItemStack itemStack) {
+        if (isAvailable(holder)) {
+          items.set(index, itemStack);
+          holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
+        } else {
+          this.holder.drop(itemStack, false);
+        }
+      }
+    };
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCursor(ServerPlayer holder) {
+    return new ContentCursor(holder) {
+      @Override
+      public void set(ItemStack itemStack) {
+        if (isAvailable()) {
+          holder.containerMenu.setCarried(itemStack);
+        } else {
+          this.holder.drop(itemStack, false);
+        }
+      }
+    };
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newDrop(ServerPlayer holder) {
+    return new ContentDrop(holder) {
+      @Override
+      public void set(ItemStack itemStack) {
+        this.holder.drop(itemStack, false);
+      }
+    };
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newViewOnly(ServerPlayer holder) {
+    return newViewOnly(holder, Placeholders.notSlot);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newViewOnly(
+      ServerPlayer holder,
+      ItemStack itemStack
+  ) {
+    return new ContentViewOnly(holder) {
+      @Override
+      public void set(ItemStack itemStack) {
+        this.holder.drop(itemStack, false);
+      }
+
+      @Override
+      public Slot asSlot(Container container, int slot, int x, int y) {
+        return new SlotViewOnly(container, slot, x, y) {
+          @Override
+          public ItemStack getOrDefault() {
+            return itemStack;
+          }
+        };
+      }
+    };
+  }
+
+  @Override
+  public org.bukkit.inventory.ItemStack asBukkitMirror(ItemStack itemStack) {
+    return CraftItemStack.asCraftMirror(itemStack);
+  }
+
+}

internal/paper26_3/build.gradle.kts

@@ -0,0 +1,42 @@
+plugins {
+  alias(libs.plugins.paperweight)
+}
+
+repositories {
+  maven("https://repo.papermc.io/repository/maven-public/")
+}
+
+// Paper is compiled with Java 25, so we have to use a Java 25 toolchain.
+java {
+  toolchain.languageVersion.set(JavaLanguageVersion.of(25))
+}
+
+// To minimize duplicate code, the adapter for 1.21.11 is built off of this module, so we need to target Java 21.
+tasks.withType<JavaCompile>().configureEach {
+  options.release = 21
+}
+
+// As a result, we have to specifically tell Gradle it's okay if our dependencies require Java 25,
+// because secretly sometimes they don't!
+configurations.matching { it.isCanBeResolved && it.name.endsWith("Classpath") }.all {
+  attributes {
+    attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 25)
+  }
+}
+
+dependencies {
+  implementation(project(":openinvapi")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+  implementation(project(":openinvcommon")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+
+  paperweight.paperDevBundle("26.3.build.+")
+}
+
+tasks.reobfJar {
+  enabled = false
+}
+
+configurations.reobf.get().outgoing.artifacts.clear()

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/InternalAccessor.java

@@ -0,0 +1,111 @@
+package com.lishid.openinv.internal.paper26_3;
+
+import com.github.jikoo.openinv.internal.Accessor;
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.AnySilentContainer;
+import com.lishid.openinv.internal.paper26_3.container.OpenEnderChest;
+import com.lishid.openinv.internal.paper26_3.container.OpenInventory;
+import com.lishid.openinv.internal.paper26_3.container.slot.OpenInventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.PlaceholderLoader;
+import com.lishid.openinv.internal.paper26_3.player.PlayerManager;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+@NullMarked
+public class InternalAccessor implements Accessor {
+
+  protected final Logger logger;
+  private final PlayerManager manager;
+  protected final InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory;
+  private final AnySilentContainer anySilentContainer;
+
+  public InternalAccessor(Logger logger, LanguageManager lang) {
+    this.logger = logger;
+    factory = createInventoryFactory();
+    manager = createPlayerManager(logger, factory);
+    anySilentContainer = createAnySilentContainer(logger, lang);
+  }
+
+  protected InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> createInventoryFactory() {
+    return new OpenInventoryFactory();
+  }
+
+  protected PlayerManager createPlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
+    return new PlayerManager(logger, factory);
+  }
+
+  protected AnySilentContainer createAnySilentContainer(
+      Logger logger,
+      LanguageManager lang
+  ) {
+    return new AnySilentContainer(logger, lang);
+  }
+
+  protected PlaceholderLoader createPlaceholderLoader() {
+    return new PlaceholderLoader();
+  }
+
+  @Override
+  public PlayerManager getPlayerManager() {
+    return manager;
+  }
+
+  @Override
+  public IAnySilentContainer getAnySilentContainer() {
+    return anySilentContainer;
+  }
+
+  @Override
+  public ISpecialPlayerInventory createPlayerInventory(Player player) {
+    return new OpenInventory(factory, player);
+  }
+
+  @Override
+  public ISpecialEnderChest createEnderChest(Player player) {
+    return new OpenEnderChest(player);
+  }
+
+  @Override
+  public <T extends ISpecialInventory> @Nullable T get(Inventory bukkitInventory, Class<T> clazz) {
+    if (!(bukkitInventory instanceof CraftInventory craftInventory)) {
+      return null;
+    }
+    Container container = craftInventory.getInventory();
+    if (clazz.isInstance(container)) {
+      return clazz.cast(container);
+    }
+    return null;
+  }
+
+  @Override
+  public void reload(ConfigurationSection config) {
+    ConfigurationSection placeholders = config.getConfigurationSection("placeholders");
+    try {
+      // Reset placeholders to defaults and try to load configuration.
+      createPlaceholderLoader().load(placeholders);
+    } catch (Exception e) {
+      logger.log(Level.WARNING, "Caught exception loading placeholder overrides!", e);
+    }
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/AnySilentContainer.java

@@ -0,0 +1,233 @@
+/*
+ * Copyright (C) 2011-2023 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.internal.paper26_3.container;
+
+import com.github.jikoo.openinv.internal.container.AnySilentContainerBase;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.paper26_3.player.PlayerManager;
+import com.github.jikoo.openinv.util.ReflectionHelper;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.core.BlockPos;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.server.level.ServerPlayerGameMode;
+import net.minecraft.world.MenuProvider;
+import net.minecraft.world.SimpleMenuProvider;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.inventory.ChestMenu;
+import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.inventory.PlayerEnderChestContainer;
+import net.minecraft.world.level.GameType;
+import net.minecraft.world.level.block.BarrelBlock;
+import net.minecraft.world.level.block.Block;
+import net.minecraft.world.level.block.ChestBlock;
+import net.minecraft.world.level.block.ShulkerBoxBlock;
+import net.minecraft.world.level.block.TrappedChestBlock;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.entity.EnderChestBlockEntity;
+import net.minecraft.world.level.block.entity.RandomizableContainerBlockEntity;
+import net.minecraft.world.level.block.state.BlockState;
+import org.bukkit.GameMode;
+import org.bukkit.Material;
+import org.bukkit.Statistic;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryHolder;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.lang.reflect.Field;
+import java.util.logging.Logger;
+
+@NullMarked
+public class AnySilentContainer extends AnySilentContainerBase {
+
+  private final Logger logger;
+  private final LanguageManager lang;
+  private @Nullable Field serverPlayerGameModeGameType;
+
+  public AnySilentContainer(Logger logger, LanguageManager lang) {
+    this.logger = logger;
+    this.lang = lang;
+    try {
+      try {
+        this.serverPlayerGameModeGameType = ServerPlayerGameMode.class.getDeclaredField("gameModeForPlayer");
+        this.serverPlayerGameModeGameType.setAccessible(true);
+      } catch (NoSuchFieldException e) {
+        logger.warning("The field ServerPlayerGameMode#gameModeForPlayer is no longer present!");
+        logger.warning("Please report this at https://github.com/Jikoo/OpenInv/issues");
+        logger.warning("Attempting to fall through using reflection. Please verify that SilentContainer does not fail.");
+        // N.B. gameModeForPlayer is (for now) declared before previousGameModeForPlayer so silent shouldn't break.
+        this.serverPlayerGameModeGameType = ReflectionHelper.grabFieldByType(ServerPlayerGameMode.class, GameType.class);
+      }
+    } catch (SecurityException e) {
+      logger.warning("Unable to directly write player game mode! SilentContainer will fail.");
+      logger.log(java.util.logging.Level.WARNING, "Error obtaining GameType field", e);
+    }
+  }
+
+  @Override
+  public boolean activateContainer(
+      final Player bukkitPlayer,
+      final boolean silentchest,
+      final org.bukkit.block.Block bukkitBlock
+  ) {
+
+    // Silent ender chest is API-only
+    if (silentchest && bukkitBlock.getType() == Material.ENDER_CHEST) {
+      bukkitPlayer.openInventory(bukkitPlayer.getEnderChest());
+      bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
+      return true;
+    }
+
+    ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
+
+    final net.minecraft.world.level.Level level = ((Entity) player).level();
+    final BlockPos blockPos = new BlockPos(bukkitBlock.getX(), bukkitBlock.getY(), bukkitBlock.getZ());
+    final BlockEntity blockEntity = level.getBlockEntity(blockPos);
+
+    if (blockEntity == null) {
+      return false;
+    }
+
+    if (blockEntity instanceof EnderChestBlockEntity enderChestTile) {
+      // Anychest ender chest. See net.minecraft.world.level.block.EnderChestBlock
+      PlayerEnderChestContainer enderChest = player.getEnderChestInventory();
+      enderChest.setActiveChest(enderChestTile);
+      player.openMenu(
+          new SimpleMenuProvider(
+              (containerCounter, playerInventory, ignored) -> {
+                MenuType<?> containers = OpenChestMenu.getChestMenuType(enderChest.getContainerSize());
+                int rows = enderChest.getContainerSize() / 9;
+                return new ChestMenu(containers, containerCounter, playerInventory, enderChest, rows);
+              }, Component.translatable("container.enderchest")
+          )
+      );
+      bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
+      return true;
+    }
+
+    if (!(blockEntity instanceof @Nullable MenuProvider menuProvider)) {
+      return false;
+    }
+
+    BlockState blockState = level.getBlockState(blockPos);
+    Block block = blockState.getBlock();
+
+    if (block instanceof ChestBlock chestBlock) {
+
+      // boolean flag: do not check if chest is blocked
+      menuProvider = chestBlock.getMenuProvider(blockState, level, blockPos, true);
+
+      if (menuProvider == null) {
+        lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+        return false;
+      }
+
+      if (block instanceof TrappedChestBlock) {
+        bukkitPlayer.incrementStatistic(Statistic.TRAPPED_CHEST_TRIGGERED);
+      } else {
+        bukkitPlayer.incrementStatistic(Statistic.CHEST_OPENED);
+      }
+    }
+
+    if (block instanceof ShulkerBoxBlock) {
+      bukkitPlayer.incrementStatistic(Statistic.SHULKER_BOX_OPENED);
+    }
+
+    if (block instanceof BarrelBlock) {
+      bukkitPlayer.incrementStatistic(Statistic.OPEN_BARREL);
+    }
+
+    // AnyChest only - SilentChest not active, container unsupported, or unnecessary.
+    if (!silentchest || player.gameMode.getGameModeForPlayer() == GameType.SPECTATOR) {
+      player.openMenu(menuProvider);
+      return true;
+    }
+
+    // SilentChest requires access to setting players' game mode directly.
+    if (this.serverPlayerGameModeGameType == null) {
+      return false;
+    }
+
+    if (blockEntity instanceof RandomizableContainerBlockEntity lootable) {
+      if (hasLootTable(lootable)) {
+        lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+        return false;
+      }
+    }
+
+    GameType gameType = player.gameMode.getGameModeForPlayer();
+    this.forceGameType(player, GameType.SPECTATOR);
+    player.openMenu(menuProvider);
+    this.forceGameType(player, gameType);
+    return true;
+  }
+
+  protected boolean hasLootTable(RandomizableContainerBlockEntity lootable) {
+    return lootable.getLootTable() != null;
+  }
+
+  @Override
+  public void deactivateContainer(final Player bukkitPlayer) {
+    if (this.serverPlayerGameModeGameType == null || bukkitPlayer.getGameMode() == GameMode.SPECTATOR) {
+      return;
+    }
+
+    ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
+
+    // Force game mode change without informing plugins or players.
+    // Regular game mode set calls GameModeChangeEvent and is cancellable.
+    GameType gameType = player.gameMode.getGameModeForPlayer();
+    this.forceGameType(player, GameType.SPECTATOR);
+
+    // ServerPlayer#closeContainer cannot be called without entering an
+    // infinite loop because this method is called during inventory close.
+    // From ServerPlayer#closeContainer -> CraftEventFactory#handleInventoryCloseEvent
+    player.containerMenu.transferTo(player.inventoryMenu, player.getBukkitEntity());
+    // From ServerPlayer#closeContainer
+    player.doCloseContainer();
+    // Regular inventory close will handle the rest - packet sending, etc.
+
+    // Revert forced game mode.
+    this.forceGameType(player, gameType);
+  }
+
+  private void forceGameType(final ServerPlayer player, final GameType gameMode) {
+    if (this.serverPlayerGameModeGameType == null) {
+      // No need to warn repeatedly, error on startup and lack of function should be enough.
+      return;
+    }
+    try {
+      this.serverPlayerGameModeGameType.setAccessible(true);
+      this.serverPlayerGameModeGameType.set(player.gameMode, gameMode);
+    } catch (IllegalArgumentException | IllegalAccessException e) {
+      logger.log(java.util.logging.Level.WARNING, "Error bypassing GameModeChangeEvent", e);
+    }
+  }
+
+  @Override
+  protected org.bukkit.block.BlockState getState(org.bukkit.block.Block block) {
+    return block.getState(false);
+  }
+
+  @Override
+  protected @Nullable InventoryHolder getHolder(Inventory inventory) {
+    return inventory.getHolder(false);
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/BaseOpenInventory.java

@@ -0,0 +1,313 @@
+package com.lishid.openinv.internal.paper26_3.container;
+
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.github.jikoo.openinv.internal.container.InternalOwned;
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.bukkit.OpenPlayerInventory;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenInventoryMenu;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.PlayerManager;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import net.minecraft.core.NonNullList;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+
+@NullMarked
+public abstract class BaseOpenInventory implements Container, InternalOwned<ServerPlayer>, ISpecialPlayerInventory {
+
+  protected final InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory;
+  protected final List<Content<ServerPlayer, ItemStack, Container, Slot>> slots;
+  private final int size;
+  protected ServerPlayer owner;
+  private int maxStackSize = 99;
+  protected @Nullable CraftInventory bukkitEntity;
+  public List<HumanEntity> transaction = new ArrayList<>();
+
+  public BaseOpenInventory(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      org.bukkit.entity.Player bukkitPlayer
+  ) {
+    this.factory = factory;
+    owner = PlayerManager.getHandle(bukkitPlayer);
+
+    // Get total size, rounding up to nearest 9 for client compatibility.
+    int rawSize = owner.getInventory().getContainerSize() + owner.inventoryMenu.getCraftSlots().getContainerSize() + 1;
+    size = ((int) Math.ceil(rawSize / 9.0)) * 9;
+
+    slots = NonNullList.withSize(size, factory.newViewOnly(owner));
+    setupSlots();
+  }
+
+  protected void setupSlots() {
+    // Top of inventory: Regular contents.
+    int nextIndex = addMainInventory();
+
+    // If inventory is expected size, we can arrange slots to be pretty.
+    Inventory ownerInv = owner.getInventory();
+    if (ownerInv.getNonEquipmentItems().size() == 36
+        && owner.inventoryMenu.getCraftSlots().getContainerSize() == 4
+        && (Inventory.EQUIPMENT_SLOT_MAPPING.size() == 5 || Inventory.EQUIPMENT_SLOT_MAPPING.size() == 7)) {
+      // Armor slots: Bottom left.
+      addArmor(36);
+      // Off-hand: Below chestplate.
+      addOffHand(46);
+      // Drop slot: Bottom right.
+      slots.set(53, factory.newDrop(owner));
+      // Cursor slot: Above drop.
+      slots.set(44, factory.newCursor(owner));
+
+      // Crafting is displayed in the bottom right corner.
+      // As we're using the pretty view, this is a 3x2.
+      addCrafting(41, true);
+      return;
+    }
+
+    // Otherwise we'll just add elements linearly.
+    nextIndex = addArmor(nextIndex);
+    nextIndex = addOffHand(nextIndex);
+    nextIndex = addCrafting(nextIndex, false);
+    slots.set(nextIndex, factory.newCursor(owner));
+    // Drop slot last.
+    slots.set(slots.size() - 1, factory.newDrop(owner));
+  }
+
+  private int addMainInventory() {
+    int listSize = owner.getInventory().getNonEquipmentItems().size();
+    // Hotbar slots are 0-8. We want those to appear on the bottom of the inventory like a normal player inventory,
+    // so everything else needs to move up a row.
+    int hotbarDiff = listSize - 9;
+    for (int localIndex = 0; localIndex < listSize; ++localIndex) {
+      InventoryType.SlotType type;
+      int invIndex;
+      if (localIndex < hotbarDiff) {
+        invIndex = localIndex + 9;
+        type = InventoryType.SlotType.CONTAINER;
+      } else {
+        type = InventoryType.SlotType.QUICKBAR;
+        invIndex = localIndex - hotbarDiff;
+      }
+
+      slots.set(
+          localIndex,
+          factory.newList(owner, invIndex, type, holder -> holder.getInventory().getNonEquipmentItems())
+      );
+    }
+    return listSize;
+  }
+
+  private int addArmor(int startIndex) {
+    // Armor slots go bottom to top; boots are first and helmet is last.
+    // Since we have to display horizontally due to space restrictions,
+    // making the left side the "top" is more user-friendly.
+    EquipmentSlot[] sorted = Inventory.EQUIPMENT_SLOT_MAPPING.int2ObjectEntrySet()
+        .stream()
+        .sorted(Comparator.comparingInt(Int2ObjectMap.Entry::getIntKey))
+        .map(Map.Entry::getValue)
+        .toArray(EquipmentSlot[]::new);
+    int localIndex = 0;
+    for (int i = sorted.length - 1; i >= 0; --i) {
+      // Skip off-hand, handled separately. Also skip non-player slots.
+      if (sorted[i].getType() != EquipmentSlot.Type.HUMANOID_ARMOR) {
+        continue;
+      }
+
+      slots.set(startIndex + localIndex, factory.newEquipment(owner, sorted[i]));
+      ++localIndex;
+    }
+
+    return startIndex + localIndex;
+  }
+
+  private int addOffHand(int startIndex) {
+    // No off-hand?
+    if (!Inventory.EQUIPMENT_SLOT_MAPPING.containsValue(EquipmentSlot.OFFHAND)) {
+      return startIndex;
+    }
+
+    slots.set(startIndex, factory.newOffHand(owner));
+    return startIndex + 1;
+  }
+
+  private int addCrafting(int startIndex, boolean pretty) {
+    int listSize = owner.inventoryMenu.getCraftSlots().getContents().size();
+    pretty &= listSize == 4;
+
+    for (int localIndex = 0; localIndex < listSize; ++localIndex) {
+      // Pretty display is a 2x2 rather than linear.
+      // If index is in top row, grid is not 2x2, or pretty is disabled, just use current index.
+      // Otherwise, subtract 2 and add 9 to start in the same position on the next row.
+      int modIndex = startIndex + (localIndex < 2 || !pretty ? localIndex : localIndex + 7);
+
+      slots.set(modIndex, factory.newCrafting(owner, localIndex));
+    }
+
+    if (pretty) {
+      slots.set(startIndex + 2, factory.newViewOnly(owner, Placeholders.craftingOutput));
+      slots.set(startIndex + 11, factory.newCraftingResult(owner));
+    }
+
+    return startIndex + listSize;
+  }
+
+  public Slot getMenuSlot(int index, int x, int y) {
+    return slots.get(index).asSlot(this, index, x, y);
+  }
+
+  public InventoryType.SlotType getSlotType(int index) {
+    return slots.get(index).getSlotType();
+  }
+
+  public abstract Component getTitle(ServerPlayer player, @Nullable OpenChestMenu<?> menu);
+
+  @Override
+  public ServerPlayer getOwnerHandle() {
+    return owner;
+  }
+
+  @Override
+  public org.bukkit.inventory.Inventory getBukkitInventory() {
+    if (bukkitEntity == null) {
+      bukkitEntity = new OpenPlayerInventory(this);
+    }
+    return bukkitEntity;
+  }
+
+  @Override
+  public void setPlayerOnline(org.bukkit.entity.Player player) {
+    ServerPlayer newOwner = PlayerManager.getHandle(player);
+    // Only transfer regular inventory - crafting and cursor slots are transient.
+    newOwner.getInventory().replaceWith(owner.getInventory());
+    owner = newOwner;
+    // Update slots to point to new inventory.
+    slots.forEach(slot -> slot.setHolder(newOwner));
+  }
+
+  @Override
+  public boolean isInUse() {
+    return !transaction.isEmpty();
+  }
+
+  @Override
+  public org.bukkit.entity.Player getPlayer() {
+    return getOwner();
+  }
+
+  @Override
+  public int getContainerSize() {
+    return size;
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return slots.stream().map(Content::get).allMatch(ItemStack::isEmpty);
+  }
+
+  @Override
+  public ItemStack getItem(int index) {
+    return slots.get(index).get();
+  }
+
+  @Override
+  public ItemStack removeItem(int index, int amount) {
+    return slots.get(index).removePartial(amount);
+  }
+
+  @Override
+  public ItemStack removeItemNoUpdate(int index) {
+    return slots.get(index).remove();
+  }
+
+  @Override
+  public void setItem(int index, ItemStack itemStack) {
+    slots.get(index).set(itemStack);
+  }
+
+  @Override
+  public int getMaxStackSize() {
+    return maxStackSize;
+  }
+
+  @Override
+  public void setMaxStackSize(int maxStackSize) {
+    this.maxStackSize = maxStackSize;
+  }
+
+  @Override
+  public void setChanged() {
+  }
+
+  @Override
+  public boolean stillValid(Player player) {
+    return true;
+  }
+
+  @Override
+  public List<ItemStack> getContents() {
+    NonNullList<ItemStack> contents = NonNullList.withSize(getContainerSize(), ItemStack.EMPTY);
+    for (int i = 0; i < getContainerSize(); ++i) {
+      contents.set(i, getItem(i));
+    }
+    return contents;
+  }
+
+  @Override
+  public void onOpen(CraftHumanEntity viewer) {
+    transaction.add(viewer);
+  }
+
+  @Override
+  public void onClose(CraftHumanEntity viewer) {
+    transaction.remove(viewer);
+  }
+
+  @Override
+  public List<HumanEntity> getViewers() {
+    return transaction;
+  }
+
+  @Override
+  public org.bukkit.entity.Player getOwner() {
+    return owner.getBukkitEntity();
+  }
+
+  @Override
+  public Location getLocation() {
+    return owner.getBukkitEntity().getLocation();
+  }
+
+  @Override
+  public void clearContent() {
+    owner.getInventory().clearContent();
+    owner.inventoryMenu.getCraftSlots().clearContent();
+    owner.inventoryMenu.slotsChanged(owner.inventoryMenu.getCraftSlots());
+    owner.containerMenu.setCarried(ItemStack.EMPTY);
+  }
+
+  public @Nullable OpenChestMenu<?> createMenu(Player player, int i, boolean viewOnly) {
+    if (player instanceof ServerPlayer serverPlayer) {
+      return new OpenInventoryMenu(factory, this, serverPlayer, i, viewOnly);
+    }
+    return null;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/OpenEnderChest.java

@@ -0,0 +1,214 @@
+package com.lishid.openinv.internal.paper26_3.container;
+
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.github.jikoo.openinv.internal.container.InternalOwned;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenEnderChestMenu;
+import com.lishid.openinv.internal.paper26_3.player.PlayerManager;
+import net.minecraft.core.NonNullList;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.chat.MutableComponent;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.ContainerHelper;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.entity.player.StackedItemContents;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.inventory.StackedContentsCompatible;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@NullMarked
+public class OpenEnderChest implements Container, StackedContentsCompatible, InternalOwned<ServerPlayer>,
+    ISpecialEnderChest {
+
+  private @Nullable CraftInventory inventory;
+  private ServerPlayer owner;
+  private NonNullList<ItemStack> items;
+  private int maxStack = 64;
+  private final List<HumanEntity> transaction = new ArrayList<>();
+
+  public OpenEnderChest(org.bukkit.entity.Player player) {
+    this.owner = PlayerManager.getHandle(player);
+    this.items = getEnderChestItems(owner);
+  }
+
+  @Override
+  public ServerPlayer getOwnerHandle() {
+    return owner;
+  }
+
+  @Override
+  public org.bukkit.inventory.Inventory getBukkitInventory() {
+    if (inventory == null) {
+      inventory = new CraftInventory(this) {
+        @Override
+        public InventoryType getType() {
+          return InventoryType.ENDER_CHEST;
+        }
+      };
+    }
+    return inventory;
+  }
+
+  @Override
+  public void setPlayerOnline(org.bukkit.entity.Player player) {
+    owner = PlayerManager.getHandle(player);
+    NonNullList<ItemStack> activeItems = getEnderChestItems(owner);
+
+    // Guard against size changing. Theoretically on Purpur all row variations still have 6 rows internally.
+    int max = Math.min(items.size(), activeItems.size());
+    for (int index = 0; index < max; ++index) {
+      activeItems.set(index, items.get(index));
+    }
+
+    items = activeItems;
+  }
+
+  protected NonNullList<ItemStack> getEnderChestItems(ServerPlayer owner) {
+    return owner.getEnderChestInventory().getItems();
+  }
+
+  @Override
+  public org.bukkit.entity.Player getPlayer() {
+    return owner.getBukkitEntity();
+  }
+
+  @Override
+  public int getContainerSize() {
+    return items.size();
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return items.stream().allMatch(ItemStack::isEmpty);
+  }
+
+  @Override
+  public ItemStack getItem(int index) {
+    return index >= 0 && index < items.size() ? items.get(index) : ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack removeItem(int index, int amount) {
+    ItemStack itemstack = ContainerHelper.removeItem(items, index, amount);
+
+    if (!itemstack.isEmpty()) {
+      setChanged();
+    }
+
+    return itemstack;
+  }
+
+  @Override
+  public ItemStack removeItemNoUpdate(int index) {
+    return index >= 0 && index < items.size() ? items.set(index, ItemStack.EMPTY) : ItemStack.EMPTY;
+  }
+
+  @Override
+  public void setItem(int index, ItemStack itemStack) {
+    if (index >= 0 && index < items.size()) {
+      items.set(index, itemStack);
+    }
+  }
+
+  @Override
+  public int getMaxStackSize() {
+    return maxStack;
+  }
+
+  @Override
+  public void setChanged() {
+    this.owner.getEnderChestInventory().setChanged();
+  }
+
+  @Override
+  public boolean stillValid(Player player) {
+    return true;
+  }
+
+  @Override
+  public List<ItemStack> getContents() {
+    return items;
+  }
+
+  @Override
+  public void onOpen(CraftHumanEntity craftHumanEntity) {
+    transaction.add(craftHumanEntity);
+  }
+
+  @Override
+  public void onClose(CraftHumanEntity craftHumanEntity) {
+    transaction.remove(craftHumanEntity);
+  }
+
+  @Override
+  public List<HumanEntity> getViewers() {
+    return transaction;
+  }
+
+  @Override
+  public org.bukkit.entity.Player getOwner() {
+    return getPlayer();
+  }
+
+  @Override
+  public void setMaxStackSize(int size) {
+    maxStack = size;
+  }
+
+  @Override
+  public @Nullable Location getLocation() {
+    return null;
+  }
+
+  @Override
+  public void clearContent() {
+    items.clear();
+    setChanged();
+  }
+
+  @Override
+  public void fillStackedContents(StackedItemContents stackedContents) {
+    for (ItemStack itemstack : items) {
+      stackedContents.accountStack(itemstack);
+    }
+  }
+
+  public Component getTitle(@Nullable OpenChestMenu<?> menu) {
+    MutableComponent component;
+    if (menu != null && menu.isViewOnly()) {
+      component = Component.translatableWithFallback("openinv.container.enderchest.viewonly", "[RO] ");
+    } else {
+      component = Component.translatableWithFallback("openinv.container.enderchest.editable", "");
+    }
+    return component
+        .append(Component.translatableWithFallback("openinv.container.enderchest.prefix", "", owner.getName()))
+        .append(Component.translatable("container.enderchest"))
+        .append(Component.translatableWithFallback("openinv.container.enderchest.suffix", " - %s", owner.getName()));
+  }
+
+  public @Nullable OpenChestMenu<?> createMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      Player player,
+      int i,
+      boolean viewOnly
+  ) {
+    if (player instanceof ServerPlayer serverPlayer) {
+      return new OpenEnderChestMenu(factory, this, serverPlayer, i, viewOnly);
+    }
+    return null;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/OpenInventory.java

@@ -0,0 +1,58 @@
+package com.lishid.openinv.internal.paper26_3.container;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import net.minecraft.ChatFormatting;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.chat.FontDescription;
+import net.minecraft.network.chat.MutableComponent;
+import net.minecraft.resources.Identifier;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.entity.Player;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public class OpenInventory extends BaseOpenInventory {
+
+  public OpenInventory(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      Player bukkitPlayer
+  ) {
+    super(factory, bukkitPlayer);
+  }
+
+  @Override
+  public Component getTitle(@Nullable ServerPlayer viewer, @Nullable OpenChestMenu<?> menu) {
+    MutableComponent component = Component.empty();
+    // Prefix for use with custom bitmap image fonts.
+    if (owner.equals(viewer)) {
+      component.append(
+          Component.translatableWithFallback("openinv.container.inventory.self", "")
+              .withStyle(style -> style
+                  .withFont(new FontDescription.Resource(Identifier.parse("openinv:font/inventory")))
+                  .withColor(ChatFormatting.WHITE)));
+    } else {
+      component.append(
+          Component.translatableWithFallback("openinv.container.inventory.other", "")
+              .withStyle(style -> style
+                  .withFont(new FontDescription.Resource(Identifier.parse("openinv:font/inventory")))
+                  .withColor(ChatFormatting.WHITE)));
+    }
+    if (menu != null && menu.isViewOnly()) {
+      component.append(Component.translatableWithFallback("openinv.container.inventory.viewonly", "[RO] "));
+    } else {
+      component.append(Component.translatableWithFallback("openinv.container.inventory.editable", ""));
+    }
+    // Normal title: "Inventory - OwnerName"
+    component.append(Component.translatableWithFallback("openinv.container.inventory.prefix", "", owner.getName()))
+        .append(Component.translatable("container.inventory"))
+        .append(Component.translatableWithFallback("openinv.container.inventory.suffix", " - %s", owner.getName()));
+    return component;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/bukkit/OpenDummyInventory.java

@@ -0,0 +1,174 @@
+package com.lishid.openinv.internal.paper26_3.container.bukkit;
+
+import com.github.jikoo.openinv.internal.container.ViewOnly;
+import net.minecraft.world.Container;
+import org.bukkit.Material;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.ItemStack;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.ListIterator;
+
+/**
+ * A locked down "empty" inventory that rejects plugin interaction.
+ */
+@NullMarked
+public class OpenDummyInventory extends CraftInventory implements ViewOnly {
+
+  private final InventoryType type;
+
+  public OpenDummyInventory(Container inventory, InventoryType type) {
+    super(inventory);
+    this.type = type;
+  }
+
+  @Override
+  public InventoryType getType() {
+    return type;
+  }
+
+  @Override
+  public @Nullable ItemStack getItem(int index) {
+    return null;
+  }
+
+  @Override
+  public void setItem(int index, @Nullable ItemStack item) {
+
+  }
+
+  @SuppressWarnings("NonApiType")
+  @Override
+  public HashMap<Integer, ItemStack> addItem(ItemStack... items) throws IllegalArgumentException {
+    return arrayToHashMap(items);
+  }
+
+  @SuppressWarnings("NonApiType")
+  @Override
+  public HashMap<Integer, ItemStack> removeItem(ItemStack... items) throws IllegalArgumentException {
+    return arrayToHashMap(items);
+  }
+
+  @SuppressWarnings("NonApiType")
+  private static HashMap<Integer, ItemStack> arrayToHashMap(ItemStack[] items) {
+    HashMap<Integer, ItemStack> ignored = new HashMap<>();
+    for (int index = 0; index < items.length; ++index) {
+      ignored.put(index, items[index]);
+    }
+    return ignored;
+  }
+
+  @Override
+  public ItemStack[] getContents() {
+    return new ItemStack[getSize()];
+  }
+
+  @Override
+  public void setContents(ItemStack[] items) throws IllegalArgumentException {
+
+  }
+
+  @Override
+  public ItemStack[] getStorageContents() {
+    return new ItemStack[getSize()];
+  }
+
+  @Override
+  public void setStorageContents(ItemStack[] items) throws IllegalArgumentException {
+
+  }
+
+  @Override
+  public boolean contains(Material material) throws IllegalArgumentException {
+    return false;
+  }
+
+  @Override
+  public boolean contains(@Nullable ItemStack item) {
+    return false;
+  }
+
+  @Override
+  public boolean contains(Material material, int amount) throws IllegalArgumentException {
+    return false;
+  }
+
+  @Override
+  public boolean contains(@Nullable ItemStack item, int amount) {
+    return false;
+  }
+
+  @Override
+  public boolean containsAtLeast(@Nullable ItemStack item, int amount) {
+    return false;
+  }
+
+  @SuppressWarnings("NonApiType")
+  @Override
+  public HashMap<Integer, ItemStack> all(
+      Material material
+  ) throws IllegalArgumentException {
+    return new HashMap<>();
+  }
+
+  @SuppressWarnings("NonApiType")
+  @Override
+  public HashMap<Integer, ItemStack> all(@Nullable ItemStack item) {
+    return new HashMap<>();
+  }
+
+  @Override
+  public int first(Material material) throws IllegalArgumentException {
+    return -1;
+  }
+
+  @Override
+  public int first(ItemStack item) {
+    return -1;
+  }
+
+  @Override
+  public int firstEmpty() {
+    return -1;
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return true;
+  }
+
+  @Override
+  public void remove(Material material) throws IllegalArgumentException {
+
+  }
+
+  @Override
+  public void remove(ItemStack item) {
+
+  }
+
+  @Override
+  public void clear(int index) {
+
+  }
+
+  @Override
+  public void clear() {
+
+  }
+
+  @Override
+  public ListIterator<ItemStack> iterator() {
+    return Collections.emptyListIterator();
+  }
+
+  @Override
+  public ListIterator<ItemStack> iterator(int index) {
+    return Collections.emptyListIterator();
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/bukkit/OpenDummyPlayerInventory.java

@@ -0,0 +1,137 @@
+package com.lishid.openinv.internal.paper26_3.container.bukkit;
+
+import net.minecraft.world.Container;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.EquipmentSlot;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.PlayerInventory;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public class OpenDummyPlayerInventory extends OpenDummyInventory implements PlayerInventory {
+
+  public OpenDummyPlayerInventory(Container inventory) {
+    super(inventory, InventoryType.PLAYER);
+  }
+
+  @Override
+  public HumanEntity getHolder() {
+    return (HumanEntity) super.getHolder();
+  }
+
+  @Override
+  public ItemStack[] getArmorContents() {
+    return new ItemStack[4];
+  }
+
+  @Override
+  public ItemStack[] getExtraContents() {
+    return new ItemStack[4];
+  }
+
+  @Override
+  public ItemStack getHelmet() {
+    return ItemStack.empty();
+  }
+
+  @Override
+  public ItemStack getChestplate() {
+    return ItemStack.empty();
+  }
+
+  @Override
+  public ItemStack getLeggings() {
+    return ItemStack.empty();
+  }
+
+  @Override
+  public ItemStack getBoots() {
+    return ItemStack.empty();
+  }
+
+  @Override
+  public void setItem(EquipmentSlot slot, @Nullable ItemStack item) {
+
+  }
+
+  @Override
+  public ItemStack getItem(EquipmentSlot slot) {
+    return ItemStack.empty();
+  }
+
+  @Override
+  public void setArmorContents(@Nullable ItemStack[] items) {
+
+  }
+
+  @Override
+  public void setExtraContents(@Nullable ItemStack[] items) {
+
+  }
+
+  @Override
+  public void setHelmet(@Nullable ItemStack helmet) {
+
+  }
+
+  @Override
+  public void setChestplate(@Nullable ItemStack chestplate) {
+
+  }
+
+  @Override
+  public void setLeggings(@Nullable ItemStack leggings) {
+
+  }
+
+  @Override
+  public void setBoots(@Nullable ItemStack boots) {
+
+  }
+
+  @Override
+  public ItemStack getItemInMainHand() {
+    return ItemStack.empty();
+  }
+
+  @Override
+  public void setItemInMainHand(@Nullable ItemStack item) {
+
+  }
+
+  @Override
+  public ItemStack getItemInOffHand() {
+    return ItemStack.empty();
+  }
+
+  @Override
+  public void setItemInOffHand(@Nullable ItemStack item) {
+
+  }
+
+  @SuppressWarnings("InlineMeSuggester")
+  @Deprecated
+  @Override
+  public ItemStack getItemInHand() {
+    return ItemStack.empty();
+  }
+
+  @Deprecated
+  @Override
+  public void setItemInHand(@Nullable ItemStack stack) {
+
+  }
+
+  @Override
+  public int getHeldItemSlot() {
+    return 0;
+  }
+
+  @Override
+  public void setHeldItemSlot(int slot) {
+
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/bukkit/OpenPlayerInventory.java

@@ -0,0 +1,218 @@
+package com.lishid.openinv.internal.paper26_3.container.bukkit;
+
+import com.google.common.base.Preconditions;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import net.minecraft.core.NonNullList;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Inventory;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.entity.Player;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.PlayerInventory;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.util.List;
+
+@NullMarked
+public class OpenPlayerInventory extends CraftInventory implements PlayerInventory {
+
+  public OpenPlayerInventory(BaseOpenInventory inventory) {
+    super(inventory);
+  }
+
+  @Override
+  public BaseOpenInventory getInventory() {
+    return (BaseOpenInventory) super.getInventory();
+  }
+
+  @Override
+  public ItemStack[] getContents() {
+    return asCraftMirror(getInventory().getOwnerHandle().getInventory().getContents());
+  }
+
+  @Override
+  public void setContents(@Nullable ItemStack[] items) {
+    Inventory internal = getInventory().getOwnerHandle().getInventory();
+    int size = internal.getContainerSize();
+    Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
+
+    for (int index = 0; index < size; ++index) {
+      if (index < items.length) {
+        internal.setItem(index, CraftItemStack.asNMSCopy(items[index]));
+      } else {
+        internal.setItem(index, net.minecraft.world.item.ItemStack.EMPTY);
+      }
+    }
+  }
+
+  @Override
+  public ItemStack[] getStorageContents() {
+    return asCraftMirror(getInventory().getOwnerHandle().getInventory().getNonEquipmentItems());
+  }
+
+  @Override
+  public void setStorageContents(@Nullable ItemStack[] items) throws IllegalArgumentException {
+    NonNullList<net.minecraft.world.item.ItemStack> list = getInventory().getOwnerHandle().getInventory().getNonEquipmentItems();
+    int size = list.size();
+    Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
+    for (int index = 0; index < items.length; ++index) {
+      list.set(index, CraftItemStack.asNMSCopy(items[index]));
+    }
+  }
+
+  @Override
+  public InventoryType getType() {
+    return InventoryType.PLAYER;
+  }
+
+  @Override
+  public Player getHolder() {
+    return getInventory().getOwner();
+  }
+
+  @Override
+  public ItemStack[] getArmorContents() {
+    return asCraftMirror(getInventory().getOwnerHandle().getInventory().getArmorContents());
+  }
+
+  @Override
+  public void setArmorContents(@Nullable ItemStack[] items) {
+    int size = Inventory.EQUIPMENT_SLOTS_SORTED_BY_INDEX.length;
+    Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
+    for (int index = 0; index < items.length; ++index) {
+      getInventory().getOwnerHandle().getInventory().equipment.set(
+          Inventory.EQUIPMENT_SLOTS_SORTED_BY_INDEX[index],
+          CraftItemStack.asNMSCopy(items[index])
+      );
+    }
+  }
+
+  @Override
+  public ItemStack[] getExtraContents() {
+    return asCraftMirror(List.of(getInventory().getOwnerHandle().getInventory().equipment.get(EquipmentSlot.OFFHAND)));
+  }
+
+  @Override
+  public void setExtraContents(@Nullable ItemStack[] items) {
+    Preconditions.checkArgument(items.length <= 1, "items.length must be <= 1");
+    for (ItemStack item : items) {
+      getInventory().getOwnerHandle().getInventory().equipment.set(EquipmentSlot.OFFHAND, CraftItemStack.asNMSCopy(item));
+    }
+  }
+
+  @Override
+  public ItemStack getHelmet() {
+    return getInventory().getOwner().getInventory().getHelmet();
+  }
+
+  @Override
+  public void setHelmet(@Nullable ItemStack helmet) {
+    getInventory().getOwner().getInventory().setHelmet(helmet);
+  }
+
+  @Override
+  public ItemStack getChestplate() {
+    return getInventory().getOwner().getInventory().getChestplate();
+  }
+
+  @Override
+  public void setChestplate(@Nullable ItemStack chestplate) {
+    getInventory().getOwner().getInventory().setChestplate(chestplate);
+  }
+
+  @Override
+  public ItemStack getLeggings() {
+    return getInventory().getOwner().getInventory().getLeggings();
+  }
+
+  @Override
+  public void setLeggings(@Nullable ItemStack leggings) {
+    getInventory().getOwner().getInventory().setLeggings(leggings);
+  }
+
+  @Override
+  public ItemStack getBoots() {
+    return getInventory().getOwner().getInventory().getBoots();
+  }
+
+  @Override
+  public void setBoots(@Nullable ItemStack boots) {
+    getInventory().getOwner().getInventory().setBoots(boots);
+  }
+
+  @Override
+  public ItemStack getItemInMainHand() {
+    return getInventory().getOwner().getInventory().getItemInMainHand();
+  }
+
+  @Override
+  public void setItemInMainHand(@Nullable ItemStack item) {
+    getInventory().getOwner().getInventory().setItemInMainHand(item);
+  }
+
+  @Override
+  public ItemStack getItemInOffHand() {
+    return getInventory().getOwner().getInventory().getItemInOffHand();
+  }
+
+  @Override
+  public void setItemInOffHand(@Nullable ItemStack item) {
+    getInventory().getOwner().getInventory().setItemInOffHand(item);
+  }
+
+  @SuppressWarnings("InlineMeSuggester")
+  @Deprecated
+  @Override
+  public ItemStack getItemInHand() {
+    return getItemInMainHand();
+  }
+
+  @SuppressWarnings("InlineMeSuggester")
+  @Deprecated
+  @Override
+  public void setItemInHand(@Nullable ItemStack stack) {
+    setItemInMainHand(stack);
+  }
+
+  @Override
+  public int getHeldItemSlot() {
+    Inventory internal = getInventory().getOwnerHandle().getInventory();
+    return internal.getNonEquipmentItems().size() - 9 + internal.getSelectedSlot();
+  }
+
+  @Override
+  public void setHeldItemSlot(int slot) {
+    slot %= 9;
+    getInventory().getOwnerHandle().getInventory().setSelectedSlot(slot);
+  }
+
+  @Override
+  public ItemStack getItem(org.bukkit.inventory.EquipmentSlot slot) {
+    return switch (slot) {
+      case HAND -> getItemInMainHand();
+      case OFF_HAND -> getItemInOffHand();
+      case FEET -> getBoots();
+      case LEGS -> getLeggings();
+      case CHEST -> getChestplate();
+      case HEAD -> getHelmet();
+      default -> throw new IllegalArgumentException("Unsupported EquipmentSlot " + slot);
+    };
+  }
+
+  @Override
+  public void setItem(org.bukkit.inventory.EquipmentSlot slot, @Nullable ItemStack item) {
+    switch (slot) {
+      case HAND -> setItemInMainHand(item);
+      case OFF_HAND -> setItemInOffHand(item);
+      case FEET -> setBoots(item);
+      case LEGS -> setLeggings(item);
+      case CHEST -> setChestplate(item);
+      case HEAD -> setHelmet(item);
+      default -> throw new IllegalArgumentException("Unsupported EquipmentSlot " + slot);
+    }
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/bukkit/OpenPlayerInventorySelf.java

@@ -0,0 +1,28 @@
+package com.lishid.openinv.internal.paper26_3.container.bukkit;
+
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import org.bukkit.inventory.ItemStack;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public class OpenPlayerInventorySelf extends OpenPlayerInventory {
+
+  private final int offset;
+
+  public OpenPlayerInventorySelf(BaseOpenInventory inventory, int offset) {
+    super(inventory);
+    this.offset = offset;
+  }
+
+  @Override
+  public @Nullable ItemStack getItem(int index) {
+    return super.getItem(offset + index);
+  }
+
+  @Override
+  public void setItem(int index, @Nullable ItemStack item) {
+    super.setItem(offset + index, item);
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/BaseOpenInventoryMenu.java

@@ -0,0 +1,273 @@
+package com.lishid.openinv.internal.paper26_3.container.menu;
+
+import com.google.common.base.Preconditions;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import com.lishid.openinv.internal.paper26_3.container.bukkit.OpenDummyPlayerInventory;
+import com.lishid.openinv.internal.paper26_3.container.bukkit.OpenPlayerInventorySelf;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentDrop;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotEquipment;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotViewOnly;
+import com.lishid.openinv.util.Permissions;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.ChestMenu;
+import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.craftbukkit.inventory.CraftInventoryView;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryView;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public class BaseOpenInventoryMenu extends OpenSyncMenu<BaseOpenInventory> {
+
+  private int offset;
+
+  public BaseOpenInventoryMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      BaseOpenInventory inventory,
+      ServerPlayer viewer,
+      int i,
+      boolean viewOnly
+  ) {
+    super(getMenuType(inventory, viewer), i, factory, inventory, viewer, viewOnly);
+  }
+
+  private static MenuType<ChestMenu> getMenuType(BaseOpenInventory inventory, ServerPlayer viewer) {
+    int size = inventory.getContainerSize();
+    // Disallow duplicate access to own main inventory contents.
+    if (inventory.getOwnerHandle().equals(viewer)) {
+      size -= viewer.getInventory().getNonEquipmentItems().size();
+      size = ((int) Math.ceil(size / 9.0)) * 9;
+    }
+
+    return getChestMenuType(size);
+  }
+
+  @Override
+  protected void preSlotSetup() {
+    offset = ownContainer ? viewer.getInventory().getNonEquipmentItems().size() : 0;
+  }
+
+  @Override
+  protected Slot getUpperSlot(int index, int x, int y) {
+    index += offset;
+    Slot slot = container.getMenuSlot(index, x, y);
+
+    // If the slot cannot be interacted with there's nothing to configure.
+    if (slot.getClass().equals(SlotViewOnly.class)) {
+      return slot;
+    }
+
+    // Remove drop slot if viewer is not allowed to use it.
+    if (slot instanceof ContentDrop.SlotDrop
+        && (viewOnly || !Permissions.INVENTORY_SLOT_DROP.hasPermission(viewer.getBukkitEntity()))) {
+      return new SlotViewOnly(container, index, x, y);
+    }
+
+    if (slot instanceof SlotEquipment equipment) {
+      if (viewOnly) {
+        return factory.wrapViewOnly(slot);
+      }
+
+      Permissions perm = switch (equipment.getEquipmentSlot()) {
+        case HEAD -> Permissions.INVENTORY_SLOT_HEAD_ANY;
+        case CHEST -> Permissions.INVENTORY_SLOT_CHEST_ANY;
+        case LEGS -> Permissions.INVENTORY_SLOT_LEGS_ANY;
+        case FEET -> Permissions.INVENTORY_SLOT_FEET_ANY;
+        // Off-hand can hold anything, not just equipment.
+        default -> null;
+      };
+
+      // If the viewer doesn't have permission, only allow equipment the viewee can equip in the slot.
+      if (perm != null && !perm.hasPermission(viewer.getBukkitEntity())) {
+        equipment.onlyEquipmentFor(container.getOwnerHandle());
+      }
+
+      // Equipment slots are a core part of the inventory, so they will always be shown.
+      return slot;
+    }
+
+    // When viewing own inventory, only allow access to equipment and drop slots (equipment allowed above).
+    if (ownContainer && !(slot instanceof ContentDrop.SlotDrop)) {
+      return new SlotViewOnly(container, index, x, y);
+    }
+
+    if (viewOnly) {
+      return factory.wrapViewOnly(slot);
+    }
+
+    return slot;
+  }
+
+  @Override
+  protected CraftInventoryView<OpenChestMenu<BaseOpenInventory>, Inventory> createBukkitEntity() {
+    org.bukkit.inventory.Inventory bukkitInventory;
+    if (viewOnly) {
+      bukkitInventory = new OpenDummyPlayerInventory(container);
+    } else if (ownContainer) {
+      bukkitInventory = new OpenPlayerInventorySelf(container, offset);
+    } else {
+      bukkitInventory = container.getBukkitInventory();
+    }
+
+    return new CraftInventoryView<>(viewer.getBukkitEntity(), bukkitInventory, this) {
+      @Override
+      public org.bukkit.inventory.@Nullable ItemStack getItem(int index) {
+        if (viewOnly || index < 0) {
+          return null;
+        }
+
+        Slot slot = slots.get(index);
+        return factory.asBukkitMirror(slot.hasItem() ? slot.getItem() : ItemStack.EMPTY);
+      }
+
+      @Override
+      public boolean isInTop(int rawSlot) {
+        return rawSlot < topSize;
+      }
+
+      @Override
+      public @Nullable Inventory getInventory(int rawSlot) {
+        if (viewOnly) {
+          return null;
+        }
+        if (rawSlot == InventoryView.OUTSIDE || rawSlot == -1) {
+          return null;
+        }
+        Preconditions.checkArgument(
+            rawSlot >= 0 && rawSlot < topSize + offset + BOTTOM_INVENTORY_SIZE,
+            "Slot %s outside of inventory",
+            rawSlot
+        );
+        if (rawSlot > topSize) {
+          return getBottomInventory();
+        }
+        Slot slot = slots.get(rawSlot);
+        if (slot.isFake()) {
+          return null;
+        }
+        return getTopInventory();
+      }
+
+      @Override
+      public int convertSlot(int rawSlot) {
+        if (viewOnly) {
+          return InventoryView.OUTSIDE;
+        }
+        if (rawSlot < 0) {
+          return rawSlot;
+        }
+        if (rawSlot < topSize) {
+          Slot slot = slots.get(rawSlot);
+          if (slot.isFake()) {
+            return InventoryView.OUTSIDE;
+          }
+          return rawSlot;
+        }
+
+        int slot = rawSlot - topSize;
+
+        if (slot >= 27) {
+          slot -= 27;
+        } else {
+          slot += 9;
+        }
+
+        return slot;
+      }
+
+      @Override
+      public InventoryType.SlotType getSlotType(int slot) {
+        if (viewOnly || slot < 0) {
+          return InventoryType.SlotType.OUTSIDE;
+        }
+        if (slot >= topSize) {
+          slot -= topSize;
+          if (slot >= 27) {
+            return InventoryType.SlotType.QUICKBAR;
+          }
+          return InventoryType.SlotType.CONTAINER;
+        }
+        return BaseOpenInventoryMenu.this.container.getSlotType(offset + slot);
+      }
+
+      @Override
+      public int countSlots() {
+        return topSize + BOTTOM_INVENTORY_SIZE;
+      }
+    };
+  }
+
+  @Override
+  public ItemStack quickMoveStack(Player player, int index) {
+    if (viewOnly) {
+      return ItemStack.EMPTY;
+    }
+
+    // See ChestMenu and InventoryMenu
+    Slot slot = this.slots.get(index);
+
+    if (!slot.hasItem() || slot.isFake()) {
+      return ItemStack.EMPTY;
+    }
+
+    ItemStack itemStack = slot.getItem();
+    ItemStack originalStack = itemStack.copy();
+
+    if (index < topSize) {
+      // If we're moving top to bottom, do a normal transfer.
+      if (!this.moveItemStackTo(itemStack, topSize, this.slots.size(), true)) {
+        return ItemStack.EMPTY;
+      }
+    } else {
+      EquipmentSlot equipmentSlot = player.getEquipmentSlotForItem(itemStack);
+      boolean movedGear = switch (equipmentSlot) {
+        // If this is gear, try to move it to the correct slot first.
+        case OFFHAND, FEET, LEGS, CHEST, HEAD -> {
+          // Locate the correct slot in the contents following the main inventory.
+          for (int extra = container.getOwnerHandle().getInventory().getNonEquipmentItems().size() - offset; extra < topSize; ++extra) {
+            Slot extraSlot = getSlot(extra);
+            if (extraSlot instanceof SlotEquipment equipSlot
+                && equipSlot.getEquipmentSlot() == equipmentSlot) {
+              // If we've found a matching slot, try to move to it.
+              // If this succeeds, even partially, we will not attempt to move to other slots.
+              // Otherwise, armor is already occupied, so we'll fall through to main inventory.
+              yield this.moveItemStackTo(itemStack, extra, extra + 1, false);
+            }
+          }
+          yield false;
+        }
+        // Non-gear gets no special treatment.
+        default -> false;
+      };
+
+      // If main inventory is not available, there's nowhere else to move.
+      if (offset != 0) {
+        if (!movedGear) {
+          return ItemStack.EMPTY;
+        }
+      } else {
+        // If we didn't move to a gear slot, try to move to a main inventory slot.
+        if (!movedGear && !this.moveItemStackTo(itemStack, 0, container.getOwnerHandle().getInventory().getNonEquipmentItems().size(), true)) {
+          return ItemStack.EMPTY;
+        }
+      }
+    }
+
+    if (itemStack.isEmpty()) {
+      slot.setByPlayer(ItemStack.EMPTY);
+    } else {
+      slot.setChanged();
+    }
+
+    return originalStack;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/OpenChestMenu.java

@@ -0,0 +1,281 @@
+package com.lishid.openinv.internal.paper26_3.container.menu;
+
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.github.jikoo.openinv.internal.container.InternalOwned;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.bukkit.OpenDummyInventory;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotViewOnly;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.ChestMenu;
+import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.craftbukkit.inventory.CraftInventoryView;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryView;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+/**
+ * An extension of {@link AbstractContainerMenu} storing and managing data common to all special inventories.
+ */
+@NullMarked
+public abstract class OpenChestMenu<T extends Container & ISpecialInventory & InternalOwned<ServerPlayer>>
+    extends AbstractContainerMenu {
+
+  protected static final int BOTTOM_INVENTORY_SIZE = 36;
+
+  protected final InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory;
+  protected final T container;
+  protected final ServerPlayer viewer;
+  protected final boolean viewOnly;
+  protected final boolean ownContainer;
+  protected final int topSize;
+  private @Nullable CraftInventoryView<OpenChestMenu<T>, Inventory> bukkitEntity;
+
+  protected OpenChestMenu(
+      MenuType<ChestMenu> type,
+      int containerCounter,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      T container,
+      ServerPlayer viewer,
+      boolean viewOnly
+  ) {
+    super(type, containerCounter);
+    this.factory = factory;
+    this.container = container;
+    this.viewer = viewer;
+    this.viewOnly = viewOnly;
+    ownContainer = container.getOwnerHandle().equals(viewer);
+    topSize = getTopSize(viewer);
+
+    preSlotSetup();
+
+    int upperRows = topSize / 9;
+    // View's upper inventory - our container
+    for (int row = 0; row < upperRows; ++row) {
+      for (int col = 0; col < 9; ++col) {
+        // x and y for client purposes, but hey, we're thorough here.
+        // Adapted from net.minecraft.world.inventory.ChestMenu
+        int x = 8 + col * 18;
+        int y = 18 + row * 18;
+        int index = row * 9 + col;
+
+        // Guard against weird inventory sizes.
+        if (index >= container.getContainerSize()) {
+          addSlot(new SlotViewOnly(container, index, x, y));
+          continue;
+        }
+
+        Slot slot = getUpperSlot(index, x, y);
+
+        addSlot(slot);
+      }
+    }
+
+    // View's lower inventory - viewer inventory
+    int playerInvPad = (upperRows - 4) * 18;
+    for (int row = 0; row < 3; ++row) {
+      for (int col = 0; col < 9; ++col) {
+        int x = 8 + col * 18;
+        int y = playerInvPad + row * 18 + 103;
+        addSlot(new Slot(viewer.getInventory(), row * 9 + col + 9, x, y));
+      }
+    }
+    // Hotbar
+    for (int col = 0; col < 9; ++col) {
+      int x = 8 + col * 18;
+      int y = playerInvPad + 161;
+      addSlot(new Slot(viewer.getInventory(), col, x, y));
+    }
+  }
+
+  public static MenuType<ChestMenu> getChestMenuType(int inventorySize) {
+    inventorySize = ((int) Math.ceil(inventorySize / 9.0)) * 9;
+    return switch (inventorySize) {
+      case 9 -> MenuType.GENERIC_9x1;
+      case 18 -> MenuType.GENERIC_9x2;
+      case 27 -> MenuType.GENERIC_9x3;
+      case 36 -> MenuType.GENERIC_9x4;
+      case 45 -> MenuType.GENERIC_9x5;
+      case 54 -> MenuType.GENERIC_9x6;
+      default -> throw new IllegalArgumentException("Inventory size unsupported: " + inventorySize);
+    };
+  }
+
+  protected void preSlotSetup() {
+  }
+
+  protected Slot getUpperSlot(int index, int x, int y) {
+    Slot slot = new Slot(container, index, x, y);
+    if (viewOnly) {
+      return factory.wrapViewOnly(slot);
+    }
+    return slot;
+  }
+
+  public boolean isViewOnly() {
+    return viewOnly;
+  }
+
+  @Override
+  public final CraftInventoryView<OpenChestMenu<T>, Inventory> getBukkitView() {
+    if (bukkitEntity == null) {
+      bukkitEntity = createBukkitEntity();
+    }
+
+    return bukkitEntity;
+  }
+
+  protected CraftInventoryView<OpenChestMenu<T>, Inventory> createBukkitEntity() {
+    Inventory top;
+    if (viewOnly) {
+      top = new OpenDummyInventory(container, container.getBukkitType());
+    } else {
+      top = container.getBukkitInventory();
+    }
+    return new CraftInventoryView<>(viewer.getBukkitEntity(), top, this) {
+      @Override
+      public @Nullable Inventory getInventory(int rawSlot) {
+        if (viewOnly) {
+          return null;
+        }
+        return super.getInventory(rawSlot);
+      }
+
+      @Override
+      public int convertSlot(int rawSlot) {
+        if (viewOnly) {
+          return InventoryView.OUTSIDE;
+        }
+        return super.convertSlot(rawSlot);
+      }
+
+      @Override
+      public InventoryType.SlotType getSlotType(int slot) {
+        if (viewOnly) {
+          return InventoryType.SlotType.OUTSIDE;
+        }
+        return super.getSlotType(slot);
+      }
+    };
+  }
+
+  private int getTopSize(ServerPlayer viewer) {
+    MenuType<?> menuType = getType();
+    if (MenuType.GENERIC_9x1.equals(menuType)) {
+      return 9;
+    } else if (MenuType.GENERIC_9x2.equals(menuType)) {
+      return 18;
+    } else if (MenuType.GENERIC_9x3.equals(menuType)) {
+      return 27;
+    } else if (MenuType.GENERIC_9x4.equals(menuType)) {
+      return 36;
+    } else if (MenuType.GENERIC_9x5.equals(menuType)) {
+      return 45;
+    } else if (MenuType.GENERIC_9x6.equals(menuType)) {
+      return 54;
+    }
+    // This is a bit gross, but allows us a safe fallthrough.
+    return menuType.create(-1, viewer.getInventory()).slots.size() - BOTTOM_INVENTORY_SIZE;
+  }
+
+  /**
+   * Reimplementation of {@link AbstractContainerMenu#moveItemStackTo(ItemStack, int, int, boolean)} that ignores fake
+   * slots and respects {@link Slot#hasItem()}.
+   *
+   * @param itemStack the stack to quick-move
+   * @param rangeLow the start of the range of slots that can be moved to, inclusive
+   * @param rangeHigh the end of the range of slots that can be moved to, exclusive
+   * @param topDown whether to start at the top of the range or bottom
+   * @return whether the stack was modified as a result of being quick-moved
+   */
+  @Override
+  protected boolean moveItemStackTo(ItemStack itemStack, int rangeLow, int rangeHigh, boolean topDown) {
+    boolean modified = false;
+    boolean stackable = itemStack.isStackable();
+    Slot firstEmpty = null;
+
+    for (int index = topDown ? rangeHigh - 1 : rangeLow;
+         !itemStack.isEmpty() && (topDown ? index >= rangeLow : index < rangeHigh);
+         index += topDown ? -1 : 1
+    ) {
+      Slot slot = slots.get(index);
+      // If the slot cannot be added to, check the next slot.
+      if (slot.isFake() || !slot.mayPlace(itemStack)) {
+        continue;
+      }
+
+      if (slot.hasItem()) {
+        // If the item isn't stackable, check the next slot.
+        if (!stackable) {
+          continue;
+        }
+        // Otherwise, add as many as we can from our stack to the slot.
+        modified |= addToExistingStack(itemStack, slot);
+      } else {
+        // If this is the first empty slot, keep track of it for later use.
+        if (firstEmpty == null) {
+          firstEmpty = slot;
+        }
+        // If the item isn't stackable, we've located the slot we're adding it to, so we're done.
+        if (!stackable) {
+          break;
+        }
+      }
+    }
+
+    // If the item hasn't been fully added yet, add as many as we can to the first open slot.
+    if (!itemStack.isEmpty() && firstEmpty != null) {
+      firstEmpty.setByPlayer(itemStack.split(Math.min(itemStack.getCount(), firstEmpty.getMaxStackSize(itemStack))));
+      firstEmpty.setChanged();
+      modified = true;
+    }
+
+    return modified;
+  }
+
+  private static boolean addToExistingStack(ItemStack itemStack, Slot slot) {
+    ItemStack existing = slot.getItem();
+
+    // If the items aren't the same, we can't add our item.
+    if (!ItemStack.isSameItemSameComponents(itemStack, existing)) {
+      return false;
+    }
+
+    int max = slot.getMaxStackSize(existing);
+    int existingCount = existing.getCount();
+
+    // If the stack is already full, we can't add more.
+    if (existingCount >= max) {
+      return false;
+    }
+
+    int total = existingCount + itemStack.getCount();
+
+    // If the existing item can accept the entirety of our item, we're done!
+    if (total <= max) {
+      itemStack.setCount(0);
+      existing.setCount(total);
+      slot.setChanged();
+      return true;
+    }
+
+    // Otherwise, add as many as we can.
+    itemStack.shrink(max - existingCount);
+    existing.setCount(max);
+    slot.setChanged();
+    return true;
+  }
+
+  @Override
+  public boolean stillValid(Player player) {
+    return true;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/OpenEnderChestMenu.java

@@ -0,0 +1,70 @@
+package com.lishid.openinv.internal.paper26_3.container.menu;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.OpenEnderChest;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.ContainerInput;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenEnderChestMenu extends OpenSyncMenu<OpenEnderChest> {
+
+  public OpenEnderChestMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      OpenEnderChest enderChest,
+      ServerPlayer viewer,
+      int containerId,
+      boolean viewOnly
+  ) {
+    super(getChestMenuType(enderChest.getContainerSize()), containerId, factory, enderChest, viewer, viewOnly);
+  }
+
+  @Override
+  public ItemStack quickMoveStack(Player player, int index) {
+    if (viewOnly) {
+      return ItemStack.EMPTY;
+    }
+
+    // See ChestMenu
+    Slot slot = this.slots.get(index);
+
+    if (slot.isFake() || !slot.hasItem()) {
+      return ItemStack.EMPTY;
+    }
+
+    ItemStack itemStack = slot.getItem();
+    ItemStack original = itemStack.copy();
+
+    if (index < topSize) {
+      if (!this.moveItemStackTo(itemStack, topSize, this.slots.size(), true)) {
+        return ItemStack.EMPTY;
+      }
+    } else if (!this.moveItemStackTo(itemStack, 0, topSize, false)) {
+      return ItemStack.EMPTY;
+    }
+
+    if (itemStack.isEmpty()) {
+      slot.setByPlayer(ItemStack.EMPTY);
+    } else {
+      slot.setChanged();
+    }
+
+    return original;
+  }
+
+  @Override
+  public void clicked(int slotIndex, int buttonNum, ContainerInput containerInput, Player player) {
+    if (viewOnly) {
+      if (containerInput == ContainerInput.QUICK_CRAFT) {
+        sendAllDataToRemote();
+      }
+    }
+    super.clicked(slotIndex, buttonNum, containerInput, player);
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/OpenInventoryMenu.java

@@ -0,0 +1,37 @@
+package com.lishid.openinv.internal.paper26_3.container.menu;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.ContainerInput;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenInventoryMenu extends BaseOpenInventoryMenu {
+
+  public OpenInventoryMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      BaseOpenInventory inventory,
+      ServerPlayer viewer,
+      int i,
+      boolean viewOnly
+  ) {
+    super(factory, inventory, viewer, i, viewOnly);
+  }
+
+  @Override
+  public void clicked(int slotIndex, int buttonNum, ContainerInput containerInput, Player player) {
+    if (viewOnly) {
+      if (containerInput == ContainerInput.QUICK_CRAFT) {
+        sendAllDataToRemote();
+      }
+    }
+    super.clicked(slotIndex, buttonNum, containerInput, player);
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/OpenSyncMenu.java

@@ -0,0 +1,169 @@
+package com.lishid.openinv.internal.paper26_3.container.menu;
+
+import com.google.common.base.Suppliers;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.github.jikoo.openinv.internal.container.InternalOwned;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotPlaceholder;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.ChestMenu;
+import net.minecraft.world.inventory.ContainerListener;
+import net.minecraft.world.inventory.ContainerSynchronizer;
+import net.minecraft.world.inventory.DataSlot;
+import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.inventory.RemoteSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Supplier;
+
+/**
+ * An extension of {@link OpenChestMenu} that supports {@link SlotPlaceholder placeholders}.
+ */
+@NullMarked
+public abstract class OpenSyncMenu<T extends Container & ISpecialInventory & InternalOwned<ServerPlayer>>
+    extends OpenChestMenu<T> {
+
+  // Syncher fields required to send placeholder items.
+  // All fields intentionally shadow AbstractContainerMenu fields so that warnings
+  // will be generated if they are no longer necessary.
+  protected @Nullable ContainerSynchronizer synchronizer;
+  protected final List<ContainerListener> listeners = new ArrayList<>();
+  private @Nullable RemoteSlot remoteCarried = RemoteSlot.PLACEHOLDER;
+  protected boolean suppressRemoteUpdates;
+
+  protected OpenSyncMenu(
+      MenuType<ChestMenu> type,
+      int containerCounter,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      T container,
+      ServerPlayer viewer,
+      boolean viewOnly
+  ) {
+    super(type, containerCounter, factory, container, viewer, viewOnly);
+  }
+
+  @Override
+  public void broadcastChanges() {
+    for (int index = 0; index < this.slots.size(); ++index) {
+      Slot slot = this.slots.get(index);
+      ItemStack itemstack = slot instanceof SlotPlaceholder placeholder ? placeholder.getOrDefault() : slot.getItem();
+      Supplier<ItemStack> supplier = Suppliers.memoize(itemstack::copy);
+      this.triggerSlotListeners(index, itemstack, supplier);
+      this.synchronizeSlotToRemote(index, itemstack, supplier);
+    }
+
+    // See private synchronizeCarriedToRemote
+    if (!suppressRemoteUpdates && !getRemoteCarried().matches(getCarried())) {
+      this.broadcastCarriedItem();
+    }
+
+    for (int index = 0; index < this.dataSlots.size(); ++index) {
+      DataSlot dataSlot = this.dataSlots.get(index);
+      int current = dataSlot.get();
+      if (dataSlot.checkAndClearUpdateFlag()) {
+        // See private updateDataSlotListeners
+        for (ContainerListener containerListener : this.listeners) {
+          containerListener.dataChanged(this, index, current);
+        }
+      }
+
+      // See private synchronizeDataSlotToRemote
+      if (!suppressRemoteUpdates && remoteDataSlots.getInt(index) != current) {
+        remoteDataSlots.set(index, current);
+        if (synchronizer != null) {
+          synchronizer.sendDataChange(this, index, current);
+        }
+      }
+    }
+  }
+
+  @Override
+  public void sendAllDataToRemote() {
+    List<ItemStack> contentsCopy = new ArrayList<>();
+    for (int index = 0; index < slots.size(); ++index) {
+      Slot slot = slots.get(index);
+      ItemStack itemStack = slot instanceof SlotPlaceholder placeholder ? placeholder.getOrDefault() : slot.getItem();
+      contentsCopy.add(itemStack.copy());
+      this.remoteSlots.get(index).force(itemStack);
+    }
+
+    getRemoteCarried().force(getCarried());
+
+    for (int index = 0; index < this.dataSlots.size(); ++index) {
+      this.remoteDataSlots.set(index, this.dataSlots.get(index).get());
+    }
+
+    if (this.synchronizer != null) {
+      this.synchronizer.sendInitialData(this, contentsCopy, this.getCarried().copy(), this.remoteDataSlots.toIntArray());
+      this.synchronizer.sendOffHandSlotChange();
+    }
+  }
+
+  protected RemoteSlot getRemoteCarried() {
+    if (remoteCarried != null) {
+      return remoteCarried;
+    }
+
+    try {
+      Field remoteCarried = AbstractContainerMenu.class.getDeclaredField("remoteCarried");
+      remoteCarried.setAccessible(true);
+      Object slot = remoteCarried.get(this);
+      if (slot instanceof RemoteSlot remoteSlot) {
+        this.remoteCarried = remoteSlot;
+      } else {
+        this.remoteCarried = RemoteSlot.PLACEHOLDER;
+      }
+    } catch (NoSuchFieldException | IllegalAccessException e) {
+      remoteCarried = RemoteSlot.PLACEHOLDER;
+    }
+
+    return remoteCarried;
+  }
+
+  // Overrides from here on are purely to capture the contents of fields that aren't exposed.
+  // Note that super calls should likely always be last! Some send data to remotes after updating state.
+  @Override
+  public void addSlotListener(ContainerListener containerListener) {
+    if (!this.listeners.contains(containerListener)) {
+      this.listeners.add(containerListener);
+    }
+    super.addSlotListener(containerListener);
+  }
+
+  @Override
+  public void setSynchronizer(ContainerSynchronizer containerSynchronizer) {
+    this.synchronizer = containerSynchronizer;
+    // Unset carried slot so we re-capture it when sending slots.
+    // setSynchronizer calls sendAllDataToRemote, so we can't just do the reflection here once after the fact.
+    this.remoteCarried = null;
+    super.setSynchronizer(containerSynchronizer);
+  }
+
+  @Override
+  public void removeSlotListener(ContainerListener containerListener) {
+    this.listeners.remove(containerListener);
+    super.removeSlotListener(containerListener);
+  }
+
+  @Override
+  public void suppressRemoteUpdates() {
+    this.suppressRemoteUpdates = true;
+    super.suppressRemoteUpdates();
+  }
+
+  @Override
+  public void resumeRemoteUpdates() {
+    this.suppressRemoteUpdates = false;
+    super.resumeRemoteUpdates();
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentCrafting.java

@@ -0,0 +1,131 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Prediction;
+import net.minecraft.world.Container;
+import net.minecraft.world.ContainerHelper;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.List;
+
+/**
+ * A slot in a survival crafting inventory. Unavailable when not online in a survival mode.
+ */
+@NullMarked
+public class ContentCrafting implements Content<ServerPlayer, ItemStack, Container, Slot> {
+
+  private final int index;
+  protected ServerPlayer holder;
+  protected List<ItemStack> items;
+
+  protected ContentCrafting(ServerPlayer holder, int index) {
+    setHolder(holder);
+    this.index = index;
+  }
+
+  public static boolean isAvailable(ServerPlayer holder) {
+    // Player must be online and not in creative - since the creative client is (semi-)authoritative,
+    // it ignores changes without extra help, and will delete the item as a result.
+    // Spectator mode is technically possible but may cause the item to be dropped if the client opens an inventory.
+    return OpenPlayer.isConnected(holder.connection) && holder.gameMode.isSurvival();
+  }
+
+  @Override
+  public void setHolder(ServerPlayer holder) {
+    this.holder = holder;
+    // Note: CraftingContainer#getItems is immutable! Be careful with updates.
+    this.items = holder.inventoryMenu.getCraftSlots().getContents();
+  }
+
+  @Override
+  public ItemStack get() {
+    return isAvailable(holder) ? items.get(index) : ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack remove() {
+    if (!isAvailable(holder)) {
+      return ItemStack.EMPTY;
+    }
+    ItemStack removed = items.remove(index);
+    if (removed.isEmpty()) {
+      return ItemStack.EMPTY;
+    }
+    holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
+    return removed;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    if (!isAvailable(holder)) {
+      return ItemStack.EMPTY;
+    }
+    ItemStack removed = ContainerHelper.removeItem(items, index, amount);
+    if (removed.isEmpty()) {
+      return ItemStack.EMPTY;
+    }
+    holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
+    return removed;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    if (isAvailable(holder)) {
+      items.set(index, itemStack);
+      holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
+    } else {
+      this.holder.drop(itemStack, false, Prediction.SERVER_ONLY);
+    }
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotCrafting(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return isAvailable(holder) ? InventoryType.SlotType.CRAFTING : InventoryType.SlotType.OUTSIDE;
+  }
+
+  public class SlotCrafting extends SlotPlaceholder {
+
+    private SlotCrafting(Container container, int index, int x, int y) {
+      super(container, index, x, y);
+    }
+
+    @Override
+    public ItemStack getOrDefault() {
+      return isAvailable(holder) ? items.get(ContentCrafting.this.index) : Placeholders.survivalOnly(holder);
+    }
+
+    @Override
+    public boolean mayPickup(Player player) {
+      return isAvailable(holder);
+    }
+
+    @Override
+    public boolean mayPlace(ItemStack itemStack) {
+      return isAvailable(holder);
+    }
+
+    @Override
+    public boolean hasItem() {
+      return isAvailable(holder) && super.hasItem();
+    }
+
+    @Override
+    public boolean isFake() {
+      return !isAvailable(holder);
+    }
+
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentCraftingResult.java

@@ -0,0 +1,49 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.InventoryMenu;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * A slot allowing viewing of the crafting result.
+ *
+ * <p>Unmodifiable because I said so. Use your own crafting grid.</p>
+ */
+@NullMarked
+class ContentCraftingResult extends ContentViewOnly {
+
+  ContentCraftingResult(ServerPlayer holder) {
+    super(holder);
+  }
+
+  @Override
+  public ItemStack get() {
+    InventoryMenu inventoryMenu = holder.inventoryMenu;
+    return inventoryMenu.getResultSlot().getItem();
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotViewOnly(container, slot, x, y) {
+      @Override
+      public ItemStack getOrDefault() {
+        if (!ContentCrafting.isAvailable(holder)) {
+          return Placeholders.survivalOnly(holder);
+        }
+        InventoryMenu inventoryMenu = holder.inventoryMenu;
+        return inventoryMenu.getResultSlot().getItem();
+      }
+    };
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return InventoryType.SlotType.RESULT;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentCursor.java

@@ -0,0 +1,121 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Prediction;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * A slot wrapping the active menu's cursor. Unavailable when not online in a survival mode.
+ */
+@NullMarked
+public class ContentCursor implements Content<ServerPlayer, ItemStack, Container, Slot> {
+
+  protected ServerPlayer holder;
+
+  protected ContentCursor(ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public void setHolder(ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public ItemStack get() {
+    return isAvailable() ? holder.containerMenu.getCarried() : ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack remove() {
+    ItemStack carried = holder.containerMenu.getCarried();
+    holder.containerMenu.setCarried(ItemStack.EMPTY);
+    return carried;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    ItemStack carried = holder.containerMenu.getCarried();
+    if (!carried.isEmpty() && carried.getCount() >= amount) {
+      ItemStack value = carried.split(amount);
+      if (carried.isEmpty()) {
+        holder.containerMenu.setCarried(ItemStack.EMPTY);
+      }
+      return value;
+    }
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    if (isAvailable()) {
+      holder.containerMenu.setCarried(itemStack);
+    } else {
+      this.holder.drop(itemStack, false, Prediction.SERVER_ONLY);
+    }
+  }
+
+  protected boolean isAvailable() {
+    // Player must be online and not in creative - since the creative client is (semi-)authoritative,
+    // it ignores changes without extra help, and will delete the item as a result.
+    // Spectator mode is technically possible but may cause the item to be dropped if the client opens an inventory.
+    return OpenPlayer.isConnected(holder.connection) && holder.gameMode.isSurvival();
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotCursor(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    // As close as possible to "not real"
+    return InventoryType.SlotType.OUTSIDE;
+  }
+
+  public class SlotCursor extends SlotPlaceholder {
+
+    private SlotCursor(Container container, int index, int x, int y) {
+      super(container, index, x, y);
+    }
+
+    @Override
+    public ItemStack getOrDefault() {
+      if (!isAvailable()) {
+        return Placeholders.survivalOnly(holder);
+      }
+      ItemStack carried = holder.containerMenu.getCarried();
+      return carried.isEmpty() ? Placeholders.cursor : carried;
+    }
+
+    @Override
+    public boolean mayPickup(Player player) {
+      return isAvailable();
+    }
+
+    @Override
+    public boolean mayPlace(ItemStack itemStack) {
+      return isAvailable();
+    }
+
+    @Override
+    public boolean hasItem() {
+      return isAvailable() && super.hasItem();
+    }
+
+    @Override
+    public boolean isFake() {
+      return true;
+    }
+
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentDrop.java

@@ -0,0 +1,92 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Prediction;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * A fake slot used to drop items. Unavailable offline.
+ */
+@NullMarked
+public class ContentDrop implements Content<ServerPlayer, ItemStack, Container, Slot> {
+
+  protected ServerPlayer holder;
+
+  protected ContentDrop(ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public void setHolder(ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public ItemStack get() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack remove() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    this.holder.drop(itemStack, false, Prediction.SERVER_ONLY);
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotDrop(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    // Behaves like dropping an item outside the screen, just by the target player.
+    return InventoryType.SlotType.OUTSIDE;
+  }
+
+  public class SlotDrop extends SlotPlaceholder {
+
+    private SlotDrop(Container container, int index, int x, int y) {
+      super(container, index, x, y);
+    }
+
+    @Override
+    public ItemStack getOrDefault() {
+      return OpenPlayer.isConnected(holder.connection)
+          ? Placeholders.drop
+          : Placeholders.blockedOffline;
+    }
+
+    @Override
+    public boolean mayPlace(ItemStack itemStack) {
+      return OpenPlayer.isConnected(holder.connection);
+    }
+
+    @Override
+    public boolean hasItem() {
+      return false;
+    }
+
+    @Override
+    public boolean isFake() {
+      return true;
+    }
+
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentEquipment.java

@@ -0,0 +1,75 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EntityEquipment;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * A slot for equipment that displays placeholders if empty.
+ */
+@NullMarked
+class ContentEquipment implements Content<ServerPlayer, ItemStack, Container, Slot> {
+
+  private EntityEquipment equipment;
+  private final ItemStack placeholder;
+  private final EquipmentSlot equipmentSlot;
+
+  ContentEquipment(ServerPlayer holder, EquipmentSlot equipmentSlot) {
+    setHolder(holder);
+    placeholder = switch (equipmentSlot) {
+      case HEAD -> Placeholders.emptyHelmet;
+      case CHEST -> Placeholders.emptyChestplate;
+      case LEGS -> Placeholders.emptyLeggings;
+      case FEET -> Placeholders.emptyBoots;
+      default -> Placeholders.emptyOffHand;
+    };
+    this.equipmentSlot = equipmentSlot;
+  }
+
+  @Override
+  public void setHolder(ServerPlayer holder) {
+    this.equipment = holder.getInventory().equipment;
+  }
+
+  @Override
+  public ItemStack get() {
+    return equipment.get(equipmentSlot);
+  }
+
+  @Override
+  public ItemStack remove() {
+    return equipment.set(equipmentSlot, ItemStack.EMPTY);
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    ItemStack current = get();
+    if (!current.isEmpty() && amount > 0) {
+      return current.split(amount);
+    }
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    equipment.set(equipmentSlot, itemStack);
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotEquipment(container, slot, x, y, placeholder, equipmentSlot);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return InventoryType.SlotType.ARMOR;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentList.java

@@ -0,0 +1,68 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.ContainerHelper;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.List;
+
+/**
+ * A normal slot backed by an item list.
+ */
+@NullMarked
+abstract class ContentList implements Content<ServerPlayer, ItemStack, Container, Slot> {
+
+  private final int index;
+  private final InventoryType.SlotType slotType;
+  private List<ItemStack> items;
+
+  ContentList(ServerPlayer holder, int index, InventoryType.SlotType slotType) {
+    this.index = index;
+    this.slotType = slotType;
+    setHolder(holder);
+  }
+
+  @Override
+  public void setHolder(ServerPlayer holder) {
+    this.items = getItems(holder);
+  }
+
+  protected abstract List<ItemStack> getItems(ServerPlayer holder);
+
+  @Override
+  public ItemStack get() {
+    return items.get(index);
+  }
+
+  @Override
+  public ItemStack remove() {
+    ItemStack removed = items.remove(index);
+    return removed.isEmpty() ? ItemStack.EMPTY : removed;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    return ContainerHelper.removeItem(items, index, amount);
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    items.set(index, itemStack);
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new Slot(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return slotType;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentOffHand.java

@@ -0,0 +1,58 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
+import net.minecraft.network.protocol.game.ClientboundContainerSetSlotPacket;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.InventoryMenu;
+import net.minecraft.world.inventory.Slot;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.Objects;
+
+/**
+ * A slot for equipment that updates held items if necessary.
+ */
+@NullMarked
+class ContentOffHand extends ContentEquipment {
+
+  private ServerPlayer holder;
+
+  ContentOffHand(ServerPlayer holder) {
+    super(holder, EquipmentSlot.OFFHAND);
+    this.holder = holder; // Redundant, but silences nullity warning.
+  }
+
+  @Override
+  public void setHolder(ServerPlayer holder) {
+    super.setHolder(holder);
+    this.holder = holder;
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return InventoryType.SlotType.QUICKBAR;
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotEquipment(container, slot, x, y, Placeholders.emptyOffHand, EquipmentSlot.OFFHAND) {
+      @Override
+      public void setChanged() {
+        if (OpenPlayer.isConnected(holder.connection) && !Objects.equals(holder.containerMenu, holder.inventoryMenu)) {
+          holder.connection.send(
+              new ClientboundContainerSetSlotPacket(
+                  holder.inventoryMenu.containerId,
+                  holder.inventoryMenu.incrementStateId(),
+                  InventoryMenu.SHIELD_SLOT,
+                  holder.getOffhandItem()
+              ));
+        }
+      }
+    };
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentViewOnly.java

@@ -0,0 +1,59 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Prediction;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * A view-only slot that can't be interacted with.
+ */
+@NullMarked
+public class ContentViewOnly implements Content<ServerPlayer, ItemStack, Container, Slot> {
+
+  protected ServerPlayer holder;
+
+  protected ContentViewOnly(ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public void setHolder(ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public ItemStack get() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack remove() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    this.holder.drop(itemStack, false, Prediction.SERVER_ONLY);
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotViewOnly(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return InventoryType.SlotType.OUTSIDE;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/OpenInventoryFactory.java

@@ -0,0 +1,115 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.List;
+import java.util.function.Function;
+
+@NullMarked
+public class OpenInventoryFactory implements InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> {
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCrafting(ServerPlayer holder, int index) {
+    return new ContentCrafting(holder, index);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCraftingResult(ServerPlayer holder) {
+    return new ContentCraftingResult(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCursor(ServerPlayer holder) {
+    return new ContentCursor(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newDrop(ServerPlayer holder) {
+    return new ContentDrop(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newEquipment(
+      ServerPlayer holder,
+      EquipmentSlot equipmentSlot
+  ) {
+    return new ContentEquipment(holder, equipmentSlot);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newList(
+      ServerPlayer holder,
+      int index,
+      InventoryType.SlotType slotType,
+      Function<ServerPlayer, List<ItemStack>> listSupplier
+  ) {
+    return new ContentList(holder, index, slotType) {
+      @Override
+      protected List<ItemStack> getItems(ServerPlayer holder) {
+        return listSupplier.apply(holder);
+      }
+    };
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newOffHand(ServerPlayer holder) {
+    return new ContentOffHand(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newViewOnly(ServerPlayer holder) {
+    return new ContentViewOnly(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newViewOnly(ServerPlayer holder, ItemStack itemStack) {
+    return new ContentViewOnly(holder) {
+      @Override
+      public Slot asSlot(Container container, int slot, int x, int y) {
+        return new SlotViewOnly(container, slot, x, y) {
+          @Override
+          public ItemStack getOrDefault() {
+            return itemStack;
+          }
+        };
+      }
+    };
+  }
+
+  @Override
+  public Slot wrapViewOnly(Slot wrapped) {
+    SlotViewOnly wrapper;
+    if (wrapped instanceof SlotPlaceholder placeholder) {
+      wrapper = new SlotViewOnly(wrapped.container, wrapped.getContainerSlot(), wrapped.x, wrapped.y) {
+        @Override
+        public ItemStack getOrDefault() {
+          return placeholder.getOrDefault();
+        }
+      };
+    } else {
+      wrapper = new SlotViewOnly(wrapped.container, wrapped.getContainerSlot(), wrapped.x, wrapped.y) {
+        @Override
+        public ItemStack getOrDefault() {
+          return wrapped.getItem();
+        }
+      };
+    }
+    wrapper.index = wrapped.index;
+    return wrapper;
+  }
+
+  @Override
+  public org.bukkit.inventory.ItemStack asBukkitMirror(ItemStack itemStack) {
+    return CraftItemStack.asBukkitMirror(itemStack);
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/SlotEquipment.java

@@ -0,0 +1,49 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public class SlotEquipment extends SlotPlaceholder {
+
+  private final ItemStack placeholder;
+  private final EquipmentSlot equipmentSlot;
+  private @Nullable ServerPlayer viewer;
+
+  SlotEquipment(Container container, int index, int x, int y, ItemStack placeholder, EquipmentSlot equipmentSlot) {
+    super(container, index, x, y);
+    this.placeholder = placeholder;
+    this.equipmentSlot = equipmentSlot;
+  }
+
+  @Override
+  public ItemStack getOrDefault() {
+    ItemStack itemStack = getItem();
+    if (!itemStack.isEmpty()) {
+      return itemStack;
+    }
+    return placeholder;
+  }
+
+  public EquipmentSlot getEquipmentSlot() {
+    return equipmentSlot;
+  }
+
+  public void onlyEquipmentFor(ServerPlayer viewer) {
+    this.viewer = viewer;
+  }
+
+  @Override
+  public boolean mayPlace(ItemStack itemStack) {
+    if (viewer == null) {
+      return true;
+    }
+
+    return equipmentSlot == EquipmentSlot.OFFHAND || viewer.getEquipmentSlotForItem(itemStack) == equipmentSlot;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/SlotPlaceholder.java

@@ -0,0 +1,22 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * An implementation of a slot as used by a menu that may have fake placeholder items.
+ *
+ * <p>Used to prevent plugins (particularly sorting plugins) from adding placeholders to inventories.</p>
+ */
+@NullMarked
+public abstract class SlotPlaceholder extends Slot {
+
+  SlotPlaceholder(Container container, int index, int x, int y) {
+    super(container, index, x, y);
+  }
+
+  public abstract ItemStack getOrDefault();
+
+}