Switch Impl types to Holderable (#11662)

* Switch Impl types to Holderable

* Fix compile issues

* more improvements

* compile fixes

* remove unneeded unwrapAndConvertHolder call

---------

Co-authored-by: Bjarne Koll <git@lynxplay.dev>

patches/api/Introduce-registry-entry-and-builders.patch

@@ -45,14 +45,12 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +import org.jetbrains.annotations.Contract;
 +import org.jetbrains.annotations.Range;
 +import org.jetbrains.annotations.Unmodifiable;
-+import org.jspecify.annotations.NullMarked;
 +import org.jspecify.annotations.Nullable;
 +
 +/**
 + * A data-centric version-specific registry entry for the {@link Enchantment} type.
 + */
 +@ApiStatus.Experimental
-+@NullMarked
 +@ApiStatus.NonExtendable
 +public interface EnchantmentRegistryEntry {
 +
@@ -372,13 +370,11 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.Contract;
 +import org.jetbrains.annotations.Range;
-+import org.jspecify.annotations.NullMarked;
 +
 +/**
 + * A data-centric version-specific registry entry for the {@link GameEvent} type.
 + */
 +@ApiStatus.Experimental
-+@NullMarked
 +@ApiStatus.NonExtendable
 +public interface GameEventRegistryEntry {
 +
@@ -423,21 +419,18 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +package io.papermc.paper.registry.data;
 +
 +import io.papermc.paper.registry.RegistryBuilder;
-+import java.util.Optional;
 +import net.kyori.adventure.key.Key;
 +import net.kyori.adventure.text.Component;
 +import org.bukkit.Art;
 +import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.Contract;
 +import org.jetbrains.annotations.Range;
-+import org.jspecify.annotations.NullMarked;
 +import org.jspecify.annotations.Nullable;
 +
 +/**
 + * A data-centric version-specific registry entry for the {@link Art} type.
 + */
 +@ApiStatus.Experimental
-+@NullMarked
 +@ApiStatus.NonExtendable
 +public interface PaintingVariantRegistryEntry {
 +
@@ -565,7 +558,10 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 + * Registry entries are not expected to be used during plugin runtime interactions with the API but are mostly
 + * exposed during registry creation/modification.
 + */
++@NullMarked
 +package io.papermc.paper.registry.data;
++
++import org.jspecify.annotations.NullMarked;
 diff --git a/src/main/java/io/papermc/paper/registry/event/RegistryEvents.java b/src/main/java/io/papermc/paper/registry/event/RegistryEvents.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/io/papermc/paper/registry/event/RegistryEvents.java

patches/api/Test-changes.patch

@@ -223,6 +223,25 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
      }
  
      private static void collectClasses(@NotNull File from, @NotNull Map<String, ClassNode> to) throws IOException {
+         if (from.isDirectory()) {
++            // Paper start - skip packages with @NullMarked
++            final File packageInfo = new File(from, "package-info.class");
++            if (packageInfo.exists()) {
++                try (final FileInputStream in = new FileInputStream(packageInfo)) {
++                    final ClassReader cr = new ClassReader(in);
++
++                    final ClassNode node = new ClassNode();
++                    cr.accept(node, ClassReader.SKIP_CODE | ClassReader.SKIP_DEBUG | ClassReader.SKIP_FRAMES);
++
++                    if (isClassNullMarked0(node)) {
++                        return; // skip packages with @NullMarked
++                    }
++                }
++            }
++            // Paper end - skip packages with @NullMarked
+             final File[] files = from.listFiles();
+             assert files != null;
+ 
 @@ -0,0 +0,0 @@ public class AnnotationTest {
          }
      }