Paper/patches/api/0243-Add-RegistryAccess-for-managing-registries.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Wed, 2 Mar 2022 13:36:21 -0800
Subject: [PATCH] Add RegistryAccess for managing registries


diff --git a/src/main/java/io/papermc/paper/registry/Reference.java b/src/main/java/io/papermc/paper/registry/Reference.java
new file mode 100644
index 0000000000000000000000000000000000000000..92ec13c2bd515fedfd5057201ae4ba15c184bacd
--- /dev/null
+++ b/src/main/java/io/papermc/paper/registry/Reference.java
@@ -0,0 +1,47 @@
+package io.papermc.paper.registry;
+
+import org.bukkit.Keyed;
+import org.bukkit.NamespacedKey;
+import org.bukkit.Registry;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Represents a reference to a server-backed registry value that may
+ * change.
+ *
+ * @param <T> type of the value
+ */
+@Deprecated(forRemoval = true, since = "1.20.4")
+public interface Reference<T extends Keyed> extends Keyed {
+
+    /**
+     * Gets the value from the registry with the key.
+     *
+     * @return the value
+     * @throws java.util.NoSuchElementException if there is no value with this key
+     */
+    @Deprecated(forRemoval = true, since = "1.20.4")
+    @NotNull T value();
+
+    /**
+     * Gets the value from the registry with the key.
+     *
+     * @return the value or null if it doesn't exist
+     */
+    @Deprecated(forRemoval = true, since = "1.20.4")
+    @Nullable T valueOrNull();
+
+    /**
+     * Creates a reference to a registered value.
+     *
+     * @param registry the registry the value is located in
+     * @param key the key to the value
+     * @param <T> the type of the value
+     * @return a reference
+     */
+    @Deprecated(forRemoval = true, since = "1.20.4")
+    static <T extends Keyed> @NotNull Reference<T> create(@NotNull Registry<T> registry, @NotNull NamespacedKey key) {
+        return new ReferenceImpl<>(registry, key);
+    }
+}
diff --git a/src/main/java/io/papermc/paper/registry/ReferenceImpl.java b/src/main/java/io/papermc/paper/registry/ReferenceImpl.java
new file mode 100644
index 0000000000000000000000000000000000000000..f29e76a6b66ddfec12ddf8db6dcb2df6083b5982
--- /dev/null
+++ b/src/main/java/io/papermc/paper/registry/ReferenceImpl.java
@@ -0,0 +1,31 @@
+package io.papermc.paper.registry;
+
+import org.bukkit.Keyed;
+import org.bukkit.NamespacedKey;
+import org.bukkit.Registry;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.NoSuchElementException;
+
+record ReferenceImpl<T extends Keyed>(@NotNull Registry<T> registry, @NotNull NamespacedKey key) implements Reference<T> {
+
+    @Override
+    public @NotNull T value() {
+        final T value = this.registry.get(this.key);
+        if (value == null) {
+            throw new NoSuchElementException("No such value with key " + this.key);
+        }
+        return value;
+    }
+
+    @Override
+    public @Nullable T valueOrNull() {
+        return this.registry.get(this.key);
+    }
+
+    @Override
+    public @NotNull NamespacedKey getKey() {
+        return this.key;
+    }
+}
diff --git a/src/main/java/io/papermc/paper/registry/RegistryAccess.java b/src/main/java/io/papermc/paper/registry/RegistryAccess.java
new file mode 100644
index 0000000000000000000000000000000000000000..e3034bd90443f355201d72c2fc9a2960c98d2649
--- /dev/null
+++ b/src/main/java/io/papermc/paper/registry/RegistryAccess.java
@@ -0,0 +1,45 @@
+package io.papermc.paper.registry;
+
+import org.bukkit.Keyed;
+import org.bukkit.Registry;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+@ApiStatus.NonExtendable
+@ApiStatus.Experimental
+public interface RegistryAccess {
+
+    /**
+     * Get the {@link RegistryAccess} instance for the server.
+     *
+     * @return the RegistryAccess instance
+     */
+    static @NotNull RegistryAccess registryAccess() {
+        return RegistryAccessHolder.INSTANCE.orElseThrow(() -> new IllegalStateException("No RegistryAccess implementation found"));
+    }
+
+    /**
+     * Gets the registry based on the type.
+     *
+     * @param type the type
+     * @return the registry or null if none found
+     * @param <T> the type
+     * @deprecated use {@link #getRegistry(RegistryKey)} with keys from {@link RegistryKey}
+     */
+    @Deprecated(since = "1.20.4", forRemoval = true)
+    <T extends Keyed> @Nullable Registry<T> getRegistry(@NotNull Class<T> type);
+
+    /**
+     * Gets the registry with the specified key.
+     *
+     * @param registryKey the key
+     * @return the registry
+     * @param <T> the type
+     * @throws java.util.NoSuchElementException if no registry with the key is found
+     * @throws IllegalArgumentException if the registry is not available yet
+     */
+    // Future note: We should have no trouble removing this generic qualifier when
+    // registry types no longer have to be "keyed" as it shouldn't break ABI or API.
+    <T extends Keyed> @NotNull Registry<T> getRegistry(@NotNull RegistryKey<T> registryKey);
+}
diff --git a/src/main/java/io/papermc/paper/registry/RegistryAccessHolder.java b/src/main/java/io/papermc/paper/registry/RegistryAccessHolder.java
new file mode 100644
index 0000000000000000000000000000000000000000..b89e19c070f97c9662f1e16309446494b30aa7c9
--- /dev/null
+++ b/src/main/java/io/papermc/paper/registry/RegistryAccessHolder.java
@@ -0,0 +1,12 @@
+package io.papermc.paper.registry;
+
+import java.util.Optional;
+import java.util.ServiceLoader;
+
+final class RegistryAccessHolder {
+
+    static final Optional<RegistryAccess> INSTANCE = ServiceLoader.load(RegistryAccess.class).findFirst();
+
+    private RegistryAccessHolder() {
+    }
+}
diff --git a/src/main/java/io/papermc/paper/registry/RegistryKey.java b/src/main/java/io/papermc/paper/registry/RegistryKey.java
index 5dde0eac9aa6354f71a910aff1d5e484deef0a5d..9908ab753e983fba6e827980de68e7cf6f6feb13 100644
--- a/src/main/java/io/papermc/paper/registry/RegistryKey.java
+++ b/src/main/java/io/papermc/paper/registry/RegistryKey.java
@@ -4,7 +4,9 @@ import net.kyori.adventure.key.Keyed;
 import org.bukkit.GameEvent;
 import org.bukkit.MusicInstrument;
 import org.bukkit.block.Biome;
+import org.bukkit.damage.DamageType;
 import org.bukkit.enchantments.Enchantment;
+import org.bukkit.entity.Wolf;
 import org.bukkit.generator.structure.Structure;
 import org.bukkit.generator.structure.StructureType;
 import org.bukkit.inventory.meta.trim.TrimMaterial;
@@ -82,4 +84,12 @@ public sealed interface RegistryKey<T> extends Keyed permits RegistryKeyImpl {
      * @see io.papermc.paper.registry.keys.TrimPatternKeys
      */
     RegistryKey<TrimPattern> TRIM_PATTERN = create("trim_pattern");
+    /**
+     * Data-driven registry for damage types.
+     */
+    RegistryKey<DamageType> DAMAGE_TYPE = create("damage_type");
+    /**
+     * Data-driven registry for wolf variants
+     */
+    RegistryKey<Wolf.Variant> WOLF_VARIANT = create("wolf_variant");
 }
diff --git a/src/main/java/io/papermc/paper/registry/RegistryKeyImpl.java b/src/main/java/io/papermc/paper/registry/RegistryKeyImpl.java
index 9ad300fa1668cb59bbd85ff8091591db69b8c9dc..791813220b2504214b1adecc69093cd600fb0f8c 100644
--- a/src/main/java/io/papermc/paper/registry/RegistryKeyImpl.java
+++ b/src/main/java/io/papermc/paper/registry/RegistryKeyImpl.java
@@ -11,9 +11,14 @@ record RegistryKeyImpl<T>(@NotNull Key key) implements RegistryKey<T> {
     static final Set<RegistryKey<?>> REGISTRY_KEYS = Sets.newIdentityHashSet();
 
     static <T> RegistryKey<T> create(@Subst("some_key") final String key) {
-        final RegistryKey<T> registryKey = new RegistryKeyImpl<>(Key.key(Key.MINECRAFT_NAMESPACE, key));
+        final RegistryKey<T> registryKey = createInternal(key);
         REGISTRY_KEYS.add(registryKey);
         return registryKey;
     }
 
+    // creates the key without adding to the internal set of keys
+    static <T> RegistryKey<T> createInternal(@Subst("some_key") final String key) {
+        return new RegistryKeyImpl<>(Key.key(Key.MINECRAFT_NAMESPACE, key));
+    }
+
 }
diff --git a/src/main/java/org/bukkit/Bukkit.java b/src/main/java/org/bukkit/Bukkit.java
index 732ed3724e784ad659cb4411dbd73b42a8330a2c..cbf660db860e73df21be426e63928f8aeec0ac90 100644
--- a/src/main/java/org/bukkit/Bukkit.java
+++ b/src/main/java/org/bukkit/Bukkit.java
@@ -2398,8 +2398,11 @@ public final class Bukkit {
      * @param tClass of the registry to get
      * @param <T> type of the registry
      * @return the corresponding registry or null if not present
+     * @deprecated use {@link io.papermc.paper.registry.RegistryAccess#getRegistry(io.papermc.paper.registry.RegistryKey)}
+     * with keys from {@link io.papermc.paper.registry.RegistryKey}
      */
     @Nullable
+    @Deprecated(since = "1.20.4")
     public static <T extends Keyed> Registry<T> getRegistry(@NotNull Class<T> tClass) {
         return server.getRegistry(tClass);
     }
diff --git a/src/main/java/org/bukkit/Registry.java b/src/main/java/org/bukkit/Registry.java
index a04d279561676e825905f5512c399d14a3d8f828..e2aea210de4f37f6ca1afe3e6fdbc790410539ac 100644
--- a/src/main/java/org/bukkit/Registry.java
+++ b/src/main/java/org/bukkit/Registry.java
@@ -129,7 +129,7 @@ public interface Registry<T extends Keyed> extends Iterable<T> {
      *
      * @see Enchantment
      */
-    Registry<Enchantment> ENCHANTMENT = Objects.requireNonNull(Bukkit.getRegistry(Enchantment.class), "No registry present for Enchantment. This is a bug.");
+    Registry<Enchantment> ENCHANTMENT = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(io.papermc.paper.registry.RegistryKey.ENCHANTMENT); // Paper
     /**
      * Server entity types.
      *
@@ -141,7 +141,7 @@ public interface Registry<T extends Keyed> extends Iterable<T> {
      *
      * @see MusicInstrument
      */
-    Registry<MusicInstrument> INSTRUMENT = Objects.requireNonNull(Bukkit.getRegistry(MusicInstrument.class), "No registry present for MusicInstrument. This is a bug.");
+    Registry<MusicInstrument> INSTRUMENT = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(io.papermc.paper.registry.RegistryKey.INSTRUMENT); // Paper
     /**
      * Default server loot tables.
      *
@@ -159,7 +159,7 @@ public interface Registry<T extends Keyed> extends Iterable<T> {
      *
      * @see PotionEffectType
      */
-    Registry<PotionEffectType> EFFECT = Objects.requireNonNull(Bukkit.getRegistry(PotionEffectType.class), "No registry present for PotionEffectType. This is a bug.");
+    Registry<PotionEffectType> EFFECT = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(io.papermc.paper.registry.RegistryKey.MOB_EFFECT); // Paper
     /**
      * Server particles.
      *
@@ -182,14 +182,16 @@ public interface Registry<T extends Keyed> extends Iterable<T> {
      * Server structures.
      *
      * @see Structure
+     * @deprecated use {@link io.papermc.paper.registry.RegistryAccess#getRegistry(io.papermc.paper.registry.RegistryKey)} with {@link io.papermc.paper.registry.RegistryKey#STRUCTURE}
      */
-    Registry<Structure> STRUCTURE = Bukkit.getRegistry(Structure.class);
+    @Deprecated(since = "1.20.4") // Paper
+    Registry<Structure> STRUCTURE = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(Structure.class); // Paper
     /**
      * Server structure types.
      *
      * @see StructureType
      */
-    Registry<StructureType> STRUCTURE_TYPE = Bukkit.getRegistry(StructureType.class);
+    Registry<StructureType> STRUCTURE_TYPE = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(io.papermc.paper.registry.RegistryKey.STRUCTURE_TYPE); // Paper
     /**
      * Sound keys.
      *
@@ -200,21 +202,25 @@ public interface Registry<T extends Keyed> extends Iterable<T> {
      * Trim materials.
      *
      * @see TrimMaterial
+     * @deprecated use {@link io.papermc.paper.registry.RegistryAccess#getRegistry(io.papermc.paper.registry.RegistryKey)} with {@link io.papermc.paper.registry.RegistryKey#TRIM_MATERIAL}
      */
-    Registry<TrimMaterial> TRIM_MATERIAL = Bukkit.getRegistry(TrimMaterial.class);
+    @Deprecated(since = "1.20.4") // Paper
+    Registry<TrimMaterial> TRIM_MATERIAL = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(TrimMaterial.class); // Paper
     /**
      * Trim patterns.
      *
      * @see TrimPattern
+     * @deprecated use {@link io.papermc.paper.registry.RegistryAccess#getRegistry(io.papermc.paper.registry.RegistryKey)} with {@link io.papermc.paper.registry.RegistryKey#TRIM_PATTERN}
      */
-    Registry<TrimPattern> TRIM_PATTERN = Bukkit.getRegistry(TrimPattern.class);
+    @Deprecated(since = "1.20.4")
+    Registry<TrimPattern> TRIM_PATTERN = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(TrimPattern.class); // Paper
     /**
      * Damage types.
      *
      * @see DamageType
      */
     @ApiStatus.Experimental
-    Registry<DamageType> DAMAGE_TYPE = Objects.requireNonNull(Bukkit.getRegistry(DamageType.class), "No registry present for DamageType. This is a bug.");
+    Registry<DamageType> DAMAGE_TYPE = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(DamageType.class); // Paper
     /**
      * Villager profession.
      *
@@ -269,7 +275,7 @@ public interface Registry<T extends Keyed> extends Iterable<T> {
      *
      * @see Wolf.Variant
      */
-    Registry<Wolf.Variant> WOLF_VARIANT = Objects.requireNonNull(Bukkit.getRegistry(Wolf.Variant.class), "No registry present for Wolf Variant. This is a bug.");
+    Registry<Wolf.Variant> WOLF_VARIANT = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(Wolf.Variant.class); // Paper
     /**
      * Map cursor types.
      *
@@ -282,7 +288,7 @@ public interface Registry<T extends Keyed> extends Iterable<T> {
      *
      * @see GameEvent
      */
-    Registry<GameEvent> GAME_EVENT = Objects.requireNonNull(Bukkit.getRegistry(GameEvent.class), "No registry present for GameEvent. This is a bug.");
+    Registry<GameEvent> GAME_EVENT = io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(io.papermc.paper.registry.RegistryKey.GAME_EVENT); // Paper
     /**
      * Get the object by its key.
      *
diff --git a/src/main/java/org/bukkit/Server.java b/src/main/java/org/bukkit/Server.java
index 395f7910f535bfd33a5676b011ab62a53e30e140..84397dd36027fffcb3e7216c877be29c31da560f 100644
--- a/src/main/java/org/bukkit/Server.java
+++ b/src/main/java/org/bukkit/Server.java
@@ -2046,8 +2046,11 @@ public interface Server extends PluginMessageRecipient, net.kyori.adventure.audi
      * @param tClass of the registry to get
      * @param <T> type of the registry
      * @return the corresponding registry or null if not present
+     * @deprecated use {@link io.papermc.paper.registry.RegistryAccess#getRegistry(io.papermc.paper.registry.RegistryKey)}
+     * with keys from {@link io.papermc.paper.registry.RegistryKey}
      */
     @Nullable
+    @Deprecated(since = "1.20.4") // Paper
     <T extends Keyed> Registry<T> getRegistry(@NotNull Class<T> tClass);
 
     /**
diff --git a/src/test/java/io/papermc/paper/registry/TestRegistryAccess.java b/src/test/java/io/papermc/paper/registry/TestRegistryAccess.java
new file mode 100644
index 0000000000000000000000000000000000000000..5e99d7d84150664f16cbbd6f58eb3a316017fe5f
--- /dev/null
+++ b/src/test/java/io/papermc/paper/registry/TestRegistryAccess.java
@@ -0,0 +1,20 @@
+package io.papermc.paper.registry;
+
+import org.bukkit.Keyed;
+import org.bukkit.Registry;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class TestRegistryAccess implements RegistryAccess {
+
+    @Override
+    @Deprecated(since = "1.20.4", forRemoval = true)
+    public @Nullable <T extends Keyed> Registry<T> getRegistry(final @NotNull Class<T> type) {
+        throw new UnsupportedOperationException("Not supported");
+    }
+
+    @Override
+    public @NotNull <T extends Keyed> Registry<T> getRegistry(final @NotNull RegistryKey<T> registryKey) {
+        throw new UnsupportedOperationException("Not supported");
+    }
+}
diff --git a/src/test/java/org/bukkit/support/TestServer.java b/src/test/java/org/bukkit/support/TestServer.java
index b208150297a23c0b4acb79135416809718f5650e..f11c639f1dc3c5034678d80bde3127a2e81a4a93 100644
--- a/src/test/java/org/bukkit/support/TestServer.java
+++ b/src/test/java/org/bukkit/support/TestServer.java
@@ -36,26 +36,11 @@ public final class TestServer {
 
         when(instance.getBukkitVersion()).thenReturn("BukkitVersion_" + TestServer.class.getPackage().getImplementationVersion());
 
-        Map<Class<? extends Keyed>, Registry<?>> registers = new HashMap<>();
-        when(instance.getRegistry(any())).then(invocationOnMock -> registers.computeIfAbsent(invocationOnMock.getArgument(0), aClass -> new Registry<Keyed>() {
-            private final Map<NamespacedKey, Keyed> cache = new HashMap<>();
-
-            @Override
-            public Keyed get(NamespacedKey key) {
-                return cache.computeIfAbsent(key, key2 -> mock(aClass, withSettings().stubOnly()));
-            }
-
-            @NotNull
-            @Override
-            public Stream<Keyed> stream() {
-                throw new UnsupportedOperationException("Not supported");
-            }
-
-            @Override
-            public Iterator<Keyed> iterator() {
-                throw new UnsupportedOperationException("Not supported");
-            }
-        }));
+        // Paper start - RegistryAccess
+        when(instance.getRegistry(any())).then(invocationOnMock -> {
+            return io.papermc.paper.registry.RegistryAccess.registryAccess().getRegistry(((Class<Keyed>)invocationOnMock.getArgument(0)));
+        });
+        // Paper end - RegistryAccess
 
         UnsafeValues unsafeValues = mock(withSettings().stubOnly());
         when(instance.getUnsafe()).thenReturn(unsafeValues);
diff --git a/src/test/resources/META-INF/services/io.papermc.paper.registry.RegistryAccess b/src/test/resources/META-INF/services/io.papermc.paper.registry.RegistryAccess
new file mode 100644
index 0000000000000000000000000000000000000000..f0a5e6d6b99aeef349fe465080ef2ff7b58617a6
--- /dev/null
+++ b/src/test/resources/META-INF/services/io.papermc.paper.registry.RegistryAccess
@@ -0,0 +1 @@
+io.papermc.paper.registry.TestRegistryAccess