Fix ItemFactory#getSpawnEgg NoSuchMethodError on older Paper builds (#4582)

bukkit/src/main/java/com/viaversion/viaversion/bukkit/platform/PaperViaInjector.java

@@ -19,11 +19,12 @@ package com.viaversion.viaversion.bukkit.platform;
 
 import com.viaversion.viaversion.bukkit.handlers.BukkitChannelInitializer;
 import io.netty.channel.Channel;
-import java.lang.reflect.Method;
-import java.lang.reflect.Proxy;
 import net.kyori.adventure.key.Key;
 import org.bukkit.Bukkit;
 
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+
 public final class PaperViaInjector {
     public static final boolean PAPER_INJECTION_METHOD = hasPaperInjectionMethod();
     public static final boolean PAPER_PROTOCOL_METHOD = hasServerProtocolMethod();
@@ -106,4 +107,12 @@ public final class PaperViaInjector {
             return false;
         }
     }
+
+    public static boolean hasMethod(final Class<?> clazz, final Class<?> returnType, final String method, final Class<?>... params) {
+        try {
+            return clazz.getDeclaredMethod(method, params).getReturnType().equals(returnType);
+        } catch (final NoSuchMethodException e) {
+            return false;
+        }
+    }
 }

bukkit/src/main/java/com/viaversion/viaversion/bukkit/providers/BukkitPickItemProvider.java

@@ -25,7 +25,6 @@ import com.viaversion.viaversion.api.protocol.version.ProtocolVersion;
 import com.viaversion.viaversion.bukkit.platform.PaperViaInjector;
 import com.viaversion.viaversion.bukkit.util.LegacyBlockToItem;
 import com.viaversion.viaversion.protocols.v1_21_2to1_21_4.provider.PickItemProvider;
-import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.GameMode;
 import org.bukkit.Location;
@@ -40,17 +39,34 @@ import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.PlayerInventory;
 import org.bukkit.inventory.meta.BlockStateMeta;
 
+import java.lang.reflect.Method;
+import java.util.UUID;
+
 public class BukkitPickItemProvider extends PickItemProvider {
     private static final BlockToItem BLOCK_TO_ITEM = BlockToItem.build();
     private static final GetStorageContents GET_STORAGE_CONTENT = GetStorageContents.build();
     private static final SetInHand SET_IN_HAND = SetInHand.build();
 
-    private static final boolean HAS_SPAWN_EGG_METHOD = PaperViaInjector.hasMethod(ItemFactory.class, "getSpawnEgg", EntityType.class);
+    private static final boolean HAS_SPAWN_EGG_METHOD = PaperViaInjector.hasMethod(ItemFactory.class, Material.class, "getSpawnEgg", EntityType.class);
+    private static final Method GET_SPAWN_EGG_ITEMSTACK_METHOD;
+
     private static final double BLOCK_RANGE = 4.5 + 1;
     private static final double BLOCK_RANGE_SQUARED = BLOCK_RANGE * BLOCK_RANGE;
     private static final double ENTITY_RANGE = 3 + 3;
     private final ViaVersionPlugin plugin;
 
+    static {
+        if (PaperViaInjector.hasMethod(ItemFactory.class, ItemStack.class, "getSpawnEgg", EntityType.class)) {
+            try {
+                GET_SPAWN_EGG_ITEMSTACK_METHOD = ItemFactory.class.getDeclaredMethod("getSpawnEgg", EntityType.class);
+            } catch (final ReflectiveOperationException e) {
+                throw new RuntimeException(e);
+            }
+        } else {
+            GET_SPAWN_EGG_ITEMSTACK_METHOD = null;
+        }
+    }
+
     public BukkitPickItemProvider(final ViaVersionPlugin plugin) {
         this.plugin = plugin;
     }
@@ -83,7 +99,7 @@ public class BukkitPickItemProvider extends PickItemProvider {
 
     @Override
     public void pickItemFromEntity(final UserConnection connection, final int entityId, final boolean includeData) {
-        if (!HAS_SPAWN_EGG_METHOD) {
+        if (!HAS_SPAWN_EGG_METHOD && GET_SPAWN_EGG_ITEMSTACK_METHOD == null) {
             return;
         }
 
@@ -102,9 +118,21 @@ public class BukkitPickItemProvider extends PickItemProvider {
                 return;
             }
 
-            final Material spawnEggType = Bukkit.getItemFactory().getSpawnEgg(entity.getType());
-            if (spawnEggType != null) {
-                pickItem(player, new ItemStack(spawnEggType, 1));
+            if (GET_SPAWN_EGG_ITEMSTACK_METHOD == null) {
+                final Material spawnEggType = Bukkit.getItemFactory().getSpawnEgg(entity.getType());
+                if (spawnEggType != null) {
+                    pickItem(player, new ItemStack(spawnEggType, 1));
+                }
+                return;
+            }
+
+            try {
+                final ItemStack spawnEggItem = (ItemStack) GET_SPAWN_EGG_ITEMSTACK_METHOD.invoke(Bukkit.getItemFactory(), entity.getType());
+                if (spawnEggItem != null) {
+                    pickItem(player, spawnEggItem);
+                }
+            } catch (final ReflectiveOperationException e) {
+                throw new RuntimeException(e);
             }
         }, player);
     }