Add RegistryRetriever for future use in registry API

paper-api/src/main/java/io/papermc/paper/registry/event/RegistryComposeEvent.java

@@ -5,6 +5,7 @@ import io.papermc.paper.registry.tag.Tag;
 import io.papermc.paper.registry.tag.TagKey;
 import org.bukkit.Keyed;
 import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.Contract;
 
 /**
  * Event object for {@link RegistryEventProvider#compose()}. This
@@ -32,6 +33,19 @@ public interface RegistryComposeEvent<T, B extends RegistryBuilder<T>> extends R
      * @param tagKey the tag key
      * @return the tag
      * @param <V> the tag value type
+     * @deprecated use {@link #retriever()}
      */
-    <V extends Keyed> Tag<V> getOrCreateTag(TagKey<V> tagKey); // TODO remove Keyed
+    @Deprecated(forRemoval = true)
+    default <V extends Keyed> Tag<V> getOrCreateTag(TagKey<V> tagKey) { // TODO remove Keyed
+        return this.retriever().getOrCreateTag(tagKey);
+    }
+
+    /**
+     * Gets the registry retriever, which can be used to retrieve or create
+     * entries in the registry.
+     *
+     * @return the registry retriever
+     */
+    @Contract(pure = true)
+    RegistryRetriever retriever();
 }

paper-api/src/main/java/io/papermc/paper/registry/event/RegistryEntryAddEvent.java

@@ -6,6 +6,7 @@ import io.papermc.paper.registry.tag.Tag;
 import io.papermc.paper.registry.tag.TagKey;
 import org.bukkit.Keyed;
 import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.Contract;
 
 /**
  * Event object for {@link RegistryEventProvider#entryAdd()}. This
@@ -40,6 +41,19 @@ public interface RegistryEntryAddEvent<T, B extends RegistryBuilder<T>> extends
      * @param tagKey the tag key
      * @return the tag
      * @param <V> the tag value type
+     * @deprecated use {@link #retriever()}
      */
-    <V extends Keyed> Tag<V> getOrCreateTag(TagKey<V> tagKey);
+    @Deprecated(forRemoval = true)
+    default <V extends Keyed> Tag<V> getOrCreateTag(final TagKey<V> tagKey) { // TODO remove Keyed
+        return this.retriever().getOrCreateTag(tagKey);
+    }
+
+    /**
+     * Gets the registry retriever, which can be used to retrieve or create
+     * entries in the registry.
+     *
+     * @return the registry retriever
+     */
+    @Contract(pure = true)
+    RegistryRetriever retriever();
 }

paper-api/src/main/java/io/papermc/paper/registry/event/RegistryRetriever.java

@@ -0,0 +1,35 @@
+package io.papermc.paper.registry.event;
+
+import io.papermc.paper.registry.TypedKey;
+import io.papermc.paper.registry.tag.Tag;
+import io.papermc.paper.registry.tag.TagKey;
+import org.bukkit.Keyed;
+import org.jetbrains.annotations.ApiStatus;
+
+@ApiStatus.NonExtendable
+public interface RegistryRetriever {
+
+    /**
+     * Gets or creates a tag for the given tag key. This tag
+     * is then required to be filled either from the built-in or
+     * custom datapack.
+     *
+     * @param tagKey the tag key
+     * @param <V> the tag value type
+     * @return the tag
+     */
+    <V extends Keyed> Tag<V> getOrCreateTag(TagKey<V> tagKey); // TODO remove Keyed
+
+    /**
+     * Gets or creates an empty instance of the given {@link TypedKey}.
+     * <br>
+     * Can only create instances if the applicable registry still supports adding
+     * new references. If the registry doesn't, this method will throw an exception.
+     *
+     * @param key the key to get or create an instance for
+     * @param <V> the type of the value associated with the key
+     * @return an instance of the given key, or a new instance if it does not exist
+     * @throws IllegalStateException if this registry does not support adding new references and the key does not exist
+     */
+    <V extends Keyed> V getOrCreate(TypedKey<V> key); // TODO remove Keyed
+}

paper-server/src/main/java/io/papermc/paper/registry/entry/RegistryEntryMeta.java

@@ -6,6 +6,7 @@ import io.papermc.paper.registry.RegistryKey;
 import io.papermc.paper.registry.TypedKey;
 import io.papermc.paper.registry.WritableCraftRegistry;
 import io.papermc.paper.registry.data.util.Conversions;
+import io.papermc.paper.registry.event.PaperRegistryRetriever;
 import io.papermc.paper.registry.event.RegistryEntryAddEventImpl;
 import io.papermc.paper.registry.event.RegistryComposeEventImpl;
 import java.util.function.BiFunction;
@@ -103,11 +104,11 @@ public sealed interface RegistryEntryMeta<M, A extends Keyed> permits RegistryEn
     ) implements ServerSide<M, A> {
 
         public RegistryEntryAddEventImpl<A, B> createEntryAddEvent(final TypedKey<A> key, final B initialBuilder, final Conversions conversions) {
-            return new RegistryEntryAddEventImpl<>(key, initialBuilder, this.apiKey(), conversions);
+            return new RegistryEntryAddEventImpl<>(key, initialBuilder, this.apiKey(), conversions, new PaperRegistryRetriever(conversions));
         }
 
         public RegistryComposeEventImpl<A, B> createPostLoadEvent(final WritableCraftRegistry<M, A, B> writableRegistry, final Conversions conversions) {
-            return new RegistryComposeEventImpl<>(this.apiKey(), writableRegistry.createApiWritableRegistry(conversions), conversions);
+            return new RegistryComposeEventImpl<>(this.apiKey(), writableRegistry.createApiWritableRegistry(conversions), conversions, new PaperRegistryRetriever(conversions));
         }
 
         @Override

paper-server/src/main/java/io/papermc/paper/registry/event/PaperRegistryRetriever.java

@@ -0,0 +1,51 @@
+package io.papermc.paper.registry.event;
+
+import io.papermc.paper.registry.PaperRegistries;
+import io.papermc.paper.registry.PaperRegistryAccess;
+import io.papermc.paper.registry.TypedKey;
+import io.papermc.paper.registry.data.util.Conversions;
+import io.papermc.paper.registry.set.NamedRegistryKeySetImpl;
+import io.papermc.paper.registry.tag.Tag;
+import io.papermc.paper.registry.tag.TagKey;
+import java.util.Optional;
+import net.minecraft.core.Holder;
+import net.minecraft.core.HolderSet;
+import net.minecraft.resources.RegistryOps;
+import net.minecraft.resources.ResourceKey;
+import org.bukkit.Keyed;
+import org.bukkit.Registry;
+import org.bukkit.craftbukkit.CraftRegistry;
+
+public final class PaperRegistryRetriever implements RegistryRetriever {
+
+    private final Conversions conversions;
+
+    public PaperRegistryRetriever(final Conversions conversions) {
+        this.conversions = conversions;
+    }
+
+    @Override
+    public <V extends Keyed> Tag<V> getOrCreateTag(final TagKey<V> tagKey) {
+        final RegistryOps.RegistryInfo<Object> registryInfo = this.conversions.lookup().lookup(PaperRegistries.registryToNms(tagKey.registryKey())).orElseThrow();
+        final HolderSet.Named<?> tagSet = registryInfo.getter().getOrThrow(PaperRegistries.toNms(tagKey));
+        return new NamedRegistryKeySetImpl<>(tagKey, tagSet);
+    }
+
+    @Override
+    public <V extends Keyed> V getOrCreate(final TypedKey<V> key) {
+        final Registry<V> registry = PaperRegistryAccess.instance().getRegistry(key.registryKey());
+        final V value = registry.get(key);
+        if (value != null) {
+            return value;
+        } else if (!(registry instanceof final CraftRegistry<V, ?> craftRegistry)) {
+            throw new IllegalStateException("Cannot create instance for key " + key + " as the registry is not a CraftRegistry");
+        } else if (!craftRegistry.constructorUsesHolder()) {
+            throw new IllegalStateException("Cannot create instance for key " + key + " as the registry does not yet support creating instances with Holder references");
+        } else {
+            final ResourceKey<? extends net.minecraft.core.Registry<Object>> resourceKey = PaperRegistries.registryToNms(key.registryKey());
+            final RegistryOps.RegistryInfo<?> registryInfo = this.conversions.lookup().lookup(resourceKey).orElseThrow(() -> new IllegalStateException("Cannot create instance for key " + key + " as the registry is not registered in the lookup"));
+            registryInfo.getter().get(PaperRegistries.toNms(key)).orElseThrow(() -> new IllegalStateException("Cannot create instance for key " + key + " as it does not exist in the registry " + resourceKey));
+            return craftRegistry.getOrThrow(key);
+        }
+    }
+}

paper-server/src/main/java/io/papermc/paper/registry/event/RegistryComposeEventImpl.java

@@ -1,27 +1,14 @@
 package io.papermc.paper.registry.event;
 
 import io.papermc.paper.plugin.lifecycle.event.PaperLifecycleEvent;
-import io.papermc.paper.registry.PaperRegistries;
 import io.papermc.paper.registry.RegistryBuilder;
 import io.papermc.paper.registry.RegistryKey;
 import io.papermc.paper.registry.data.util.Conversions;
-import io.papermc.paper.registry.set.NamedRegistryKeySetImpl;
-import io.papermc.paper.registry.tag.Tag;
-import io.papermc.paper.registry.tag.TagKey;
-import net.minecraft.core.HolderSet;
-import net.minecraft.resources.RegistryOps;
-import org.bukkit.Keyed;
 
 public record RegistryComposeEventImpl<T, B extends RegistryBuilder<T>>(
     RegistryKey<T> registryKey,
     WritableRegistry<T, B> registry,
-    Conversions conversions
+    Conversions conversions,
+    RegistryRetriever retriever
 ) implements RegistryComposeEvent<T, B>, PaperLifecycleEvent {
-
-    @Override
-    public <V extends Keyed> Tag<V> getOrCreateTag(final TagKey<V> tagKey) {
-        final RegistryOps.RegistryInfo<Object> registryInfo = this.conversions.lookup().lookup(PaperRegistries.registryToNms(tagKey.registryKey())).orElseThrow();
-        final HolderSet.Named<?> tagSet = registryInfo.getter().getOrThrow(PaperRegistries.toNms(tagKey));
-        return new NamedRegistryKeySetImpl<>(tagKey, tagSet);
-    }
 }

paper-server/src/main/java/io/papermc/paper/registry/event/RegistryEntryAddEventImpl.java

@@ -1,29 +1,16 @@
 package io.papermc.paper.registry.event;
 
 import io.papermc.paper.plugin.lifecycle.event.PaperLifecycleEvent;
-import io.papermc.paper.registry.PaperRegistries;
 import io.papermc.paper.registry.RegistryBuilder;
 import io.papermc.paper.registry.RegistryKey;
 import io.papermc.paper.registry.TypedKey;
 import io.papermc.paper.registry.data.util.Conversions;
-import io.papermc.paper.registry.set.NamedRegistryKeySetImpl;
-import io.papermc.paper.registry.tag.Tag;
-import io.papermc.paper.registry.tag.TagKey;
-import net.minecraft.core.HolderSet;
-import net.minecraft.resources.RegistryOps;
-import org.bukkit.Keyed;
 
 public record RegistryEntryAddEventImpl<T, B extends RegistryBuilder<T>>(
     TypedKey<T> key,
     B builder,
     RegistryKey<T> registryKey,
-    Conversions conversions
+    Conversions conversions,
+    RegistryRetriever retriever
 ) implements RegistryEntryAddEvent<T, B>, PaperLifecycleEvent {
-
-    @Override
-    public <V extends Keyed> Tag<V> getOrCreateTag(final TagKey<V> tagKey) {
-        final RegistryOps.RegistryInfo<Object> registryInfo = this.conversions.lookup().lookup(PaperRegistries.registryToNms(tagKey.registryKey())).orElseThrow();
-        final HolderSet.Named<?> tagSet = registryInfo.getter().getOrThrow(PaperRegistries.toNms(tagKey));
-        return new NamedRegistryKeySetImpl<>(tagKey, tagSet);
-    }
 }

paper-server/src/main/java/org/bukkit/craftbukkit/CraftRegistry.java

@@ -4,6 +4,7 @@ import com.google.common.base.Preconditions;
 import io.papermc.paper.registry.PaperRegistries;
 import io.papermc.paper.registry.RegistryAccess;
 import io.papermc.paper.registry.RegistryKey;
+import io.papermc.paper.registry.TypedKey;
 import io.papermc.paper.registry.entry.RegistryEntryMeta;
 import io.papermc.paper.registry.set.NamedRegistryKeySetImpl;
 import io.papermc.paper.registry.tag.Tag;
@@ -245,6 +246,10 @@ public class CraftRegistry<B extends Keyed, M> implements Registry<B> {
         return this.minecraftToBukkit.supportsDirectHolders();
     }
 
+    public boolean constructorUsesHolder() {
+        return this.minecraftToBukkit.constructorUsesHolder();
+    }
+
     @Override
     public NamespacedKey getKey(final B value) {
         if (value instanceof Holderable<?> holderable) {

test-plugin/src/main/java/io/papermc/testplugin/TestPluginBootstrap.java

@@ -2,6 +2,11 @@ package io.papermc.testplugin;
 
 import io.papermc.paper.plugin.bootstrap.BootstrapContext;
 import io.papermc.paper.plugin.bootstrap.PluginBootstrap;
+import io.papermc.paper.registry.TypedKey;
+import io.papermc.paper.registry.event.RegistryEvents;
+import io.papermc.paper.registry.keys.WolfVariantKeys;
+import net.kyori.adventure.key.Key;
+import org.bukkit.entity.Wolf;
 import org.jetbrains.annotations.NotNull;
 
 public class TestPluginBootstrap implements PluginBootstrap {
@@ -9,6 +14,11 @@ public class TestPluginBootstrap implements PluginBootstrap {
     @Override
     public void bootstrap(@NotNull BootstrapContext context) {
         // io.papermc.testplugin.brigtests.Registration.registerViaBootstrap(context);
+
+        context.getLifecycleManager().registerEventHandler(RegistryEvents.ENCHANTMENT.compose(), event -> {
+            final Wolf.Variant v = event.retriever().getOrCreate(WolfVariantKeys.create(Key.key("mm:test")));
+            System.out.println("test");
+        });
     }
 
 }