Use preconditions

paper-api/src/main/java/io/papermc/paper/command/brigadier/CommandSourceStack.java

@@ -2,9 +2,12 @@ package io.papermc.paper.command.brigadier;
 
 import com.mojang.brigadier.RedirectModifier;
 import com.mojang.brigadier.tree.CommandNode;
+import net.kyori.adventure.text.ComponentLike;
+import org.bukkit.GameRule;
 import org.bukkit.Location;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Entity;
+import org.bukkit.entity.Player;
 import org.jetbrains.annotations.ApiStatus;
 import org.jspecify.annotations.Nullable;
 
@@ -67,4 +70,34 @@ public interface CommandSourceStack {
      * @see com.mojang.brigadier.builder.ArgumentBuilder#fork(CommandNode, RedirectModifier)
      */
     CommandSourceStack withExecutor(Entity executor);
+
+    /**
+     * Sends a system message to the {@link #getExecutor()} if it is a {@link Player},
+     * otherwise sends a system message to the {@link #getSender()}.
+     *
+     * @param message the message to send
+     */
+    void sendToTarget(ComponentLike message);
+
+    /**
+     * Sends a system message to the {@link #getSender()}, admins, and console indicating successful command execution
+     * according to vanilla semantics.
+     *
+     * <p>This currently includes checking for environments with suppressed output,
+     * {@link GameRule#SEND_COMMAND_FEEDBACK}, and {@link GameRule#LOG_ADMIN_COMMANDS}.</p>
+     *
+     * @param message the message to send
+     * @param allowInformingAdmins whether admins and console may be informed of this success
+     */
+    void sendSuccess(ComponentLike message, boolean allowInformingAdmins);
+
+    /**
+     * Sends a system message indicating a failed command execution to the {@link #getSender()}.
+     * Does not apply red styling to the message as vanilla does to allow for custom failure message styling.
+     *
+     * <p>Respects vanilla semantics for accepting failure output and suppressed output environments.</p>
+     *
+     * @param message the message to send
+     */
+    void sendFailure(ComponentLike message);
 }

paper-server/src/main/java/io/papermc/paper/command/brigadier/PaperCommandSourceStack.java

@@ -2,6 +2,8 @@ package io.papermc.paper.command.brigadier;
 
 import com.destroystokyo.paper.brigadier.BukkitBrigadierCommandSource;
 import com.google.common.base.Preconditions;
+import io.papermc.paper.adventure.PaperAdventure;
+import net.kyori.adventure.text.ComponentLike;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.phys.Vec2;
 import net.minecraft.world.phys.Vec3;
@@ -26,14 +28,12 @@ public interface PaperCommandSourceStack extends CommandSourceStack, BukkitBriga
     }
 
     @Override
-    @NonNull
-    default CommandSender getSender() {
+    default @NonNull CommandSender getSender() {
         return this.getHandle().getBukkitSender();
     }
 
     @Override
-    @Nullable
-    default Entity getExecutor() {
+    default @Nullable Entity getExecutor() {
         net.minecraft.world.entity.Entity nmsEntity = this.getHandle().getEntity();
         if (nmsEntity == null) {
             return null;
@@ -43,11 +43,29 @@ public interface PaperCommandSourceStack extends CommandSourceStack, BukkitBriga
     }
 
     @Override
-    default CommandSourceStack withExecutor(@NonNull Entity executor) {
+    default @NonNull CommandSourceStack withExecutor(@NonNull Entity executor) {
         Preconditions.checkNotNull(executor, "Executor cannot be null.");
         return this.getHandle().withEntity(((CraftEntity) executor).getHandle());
     }
 
+    @Override
+    default void sendToTarget(final @NonNull ComponentLike message) {
+        Preconditions.checkNotNull(message, "message cannot be null.");
+        this.getHandle().sendSystemMessage(PaperAdventure.asVanilla(message.asComponent()));
+    }
+
+    @Override
+    default void sendSuccess(final @NonNull ComponentLike message, final boolean allowInformingAdmins) {
+        Preconditions.checkNotNull(message, "message cannot be null.");
+        this.getHandle().sendSuccess(() -> PaperAdventure.asVanilla(message.asComponent()), allowInformingAdmins);
+    }
+
+    @Override
+    default void sendFailure(final @NonNull ComponentLike message) {
+        Preconditions.checkNotNull(message, "message cannot be null.");
+        this.getHandle().sendFailure(PaperAdventure.asVanilla(message.asComponent()), false);
+    }
+
     // OLD METHODS
     @Override
     default org.bukkit.entity.Entity getBukkitEntity() {

test-plugin/src/main/java/io/papermc/testplugin/brigtests/Registration.java

@@ -1,6 +1,8 @@
 package io.papermc.testplugin.brigtests;
 
 import com.mojang.brigadier.Command;
+import com.mojang.brigadier.arguments.BoolArgumentType;
+import com.mojang.brigadier.arguments.StringArgumentType;
 import io.papermc.paper.command.brigadier.BasicCommand;
 import io.papermc.paper.command.brigadier.CommandSourceStack;
 import io.papermc.paper.command.brigadier.Commands;
@@ -19,6 +21,8 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.minimessage.MiniMessage;
 import org.bukkit.Material;
 import org.bukkit.command.CommandSender;
 import org.bukkit.command.defaults.BukkitCommand;
@@ -45,7 +49,7 @@ public final class Registration {
                 .then(
                     Commands.argument("name", ArgumentTypes.resource(RegistryKey.ENCHANTMENT))
                         .executes(ctx -> {
-                            ctx.getSource().getSender().sendPlainMessage(ctx.getArgument("name", Enchantment.class).toString());
+                            ctx.getSource().sendSuccess(Component.text(ctx.getArgument("name", Enchantment.class).toString()), false);
                             return Command.SINGLE_SUCCESS;
                         })
                 ).build()
@@ -55,7 +59,7 @@ public final class Registration {
                     Commands.argument("key", ArgumentTypes.resourceKey(RegistryKey.ENCHANTMENT))
                         .executes(ctx -> {
                             final TypedKey<Enchantment> key = RegistryArgumentExtractor.getTypedKey(ctx, RegistryKey.ENCHANTMENT, "key");
-                            ctx.getSource().getSender().sendPlainMessage(key.toString());
+                            ctx.getSource().sendSuccess(Component.text(key.toString()), false);
                             return Command.SINGLE_SUCCESS;
                         })
                 ).build()
@@ -65,7 +69,7 @@ public final class Registration {
                       Commands.argument("pos", ArgumentTypes.finePosition(false))
                           .executes(ctx -> {
                               final FinePositionResolver position = ctx.getArgument("pos", FinePositionResolver.class);
-                              ctx.getSource().getSender().sendPlainMessage("Position: " + position.resolve(ctx.getSource()));
+                              ctx.getSource().sendSuccess(Component.text("Position: " + position.resolve(ctx.getSource())), false);
                               return Command.SINGLE_SUCCESS;
                           })
                   ).build()
@@ -73,7 +77,7 @@ public final class Registration {
             // ensure plugin commands override
             commands.register(Commands.literal("tag")
                     .executes(ctx -> {
-                        ctx.getSource().getSender().sendPlainMessage("overriden command");
+                        ctx.getSource().sendSuccess(Component.text("overriden command"), false);
                         return Command.SINGLE_SUCCESS;
                     })
                     .build(),
@@ -88,7 +92,7 @@ public final class Registration {
                     .then(Commands.literal("sub_command")
                         .requires(source -> source.getSender().hasPermission("testplugin.test"))
                         .executes(ctx -> {
-                            ctx.getSource().getSender().sendPlainMessage("root_command sub_command");
+                            ctx.getSource().sendSuccess(Component.text("root_command sub_command"), false);
                             return Command.SINGLE_SUCCESS;
                         })).build(),
                 null,
@@ -165,14 +169,14 @@ public final class Registration {
                     .then(Commands.literal("item")
                         .then(Commands.argument("mat", MaterialArgumentType.item())
                             .executes(ctx -> {
-                                ctx.getSource().getSender().sendPlainMessage(ctx.getArgument("mat", Material.class).name());
+                                ctx.getSource().sendSuccess(Component.text(ctx.getArgument("mat", Material.class).name()), false);
                                 return Command.SINGLE_SUCCESS;
                             })
                         )
                     ).then(Commands.literal("block")
                         .then(Commands.argument("mat", MaterialArgumentType.block())
                             .executes(ctx -> {
-                                ctx.getSource().getSender().sendPlainMessage(ctx.getArgument("mat", Material.class).name());
+                                ctx.getSource().sendSuccess(Component.text(ctx.getArgument("mat", Material.class).name()), false);
                                 return Command.SINGLE_SUCCESS;
                             })
                         )
@@ -181,6 +185,21 @@ public final class Registration {
                 null,
                 Collections.emptyList()
             );
+
+            commands.register(Commands.literal("send_success")
+                            .then(Commands.argument("allow_inform_admins", BoolArgumentType.bool())
+                                .then(Commands.argument("msg", StringArgumentType.greedyString())
+                                        .executes(ctx -> {
+                                            ctx.getSource().sendSuccess(
+                                                MiniMessage.miniMessage().deserialize(StringArgumentType.getString(ctx, "msg")),
+                                                BoolArgumentType.getBool(ctx, "allow_inform_admins")
+                                            );
+                                            return Command.SINGLE_SUCCESS;
+                                        })))
+                            .build(),
+                    null,
+                    Collections.emptyList()
+            );
         });
 
         lifecycleManager.registerEventHandler(LifecycleEvents.COMMANDS.newHandler(event -> {
@@ -188,8 +207,8 @@ public final class Registration {
             commands.register(Commands.literal("heya")
                     .then(Commands.argument("range", ArgumentTypes.doubleRange())
                         .executes((ct) -> {
-                            ct.getSource().getSender().sendPlainMessage(ct.getArgument("range", DoubleRangeProvider.class).range().toString());
-                            return 1;
+                            ct.getSource().sendSuccess(Component.text(ct.getArgument("range", DoubleRangeProvider.class).range().toString()), false);
+                            return Command.SINGLE_SUCCESS;
                         })
                     ).build(),
                 null,