Fix a bug where the capabilities would be compared with itself

Author: ramidzkh

patchwork-capabilities/src/main/java/com/patchworkmc/impl/capability/BaseCapabilityProvider.java

@@ -40,6 +40,10 @@ public void gatherCapabilities(@Nullable ICapabilityProvider parent) {
 		AttachCapabilitiesEvent<T> event = new AttachCapabilitiesEvent<>(baseClass, provider);
 		MinecraftForge.EVENT_BUS.post(event);
 
-		capabilities = !event.getCapabilities().isEmpty() || parent != null ? new CapabilityDispatcher(event.getCapabilities(), event.getListeners(), parent) : null;
+		if (!event.getCapabilities().isEmpty() || parent != null) {
+			capabilities = new CapabilityDispatcher(event.getCapabilities(), event.getListeners(), parent);
+		} else {
+			capabilities = null;
+		}
 	}
 }

patchwork-capabilities/src/main/java/com/patchworkmc/mixin/capability/ItemEntityMixin.java

@@ -33,10 +33,10 @@
 public class ItemEntityMixin {
 	@Inject(method = "merge", at = @At("HEAD"), cancellable = true)
 	private static void merge(ItemEntity targetEntity, ItemStack targetStack, ItemEntity sourceEntity, ItemStack sourceStack, CallbackInfo callbackInfo) {
-		CapabilityProviderHolder a = (CapabilityProviderHolder) (Object) targetStack;
-		CapabilityProviderHolder b = (CapabilityProviderHolder) (Object) targetStack;
+		CapabilityProviderHolder source = (CapabilityProviderHolder) (Object) sourceStack;
+		CapabilityProviderHolder target = (CapabilityProviderHolder) (Object) targetStack;
 
-		if (!a.areCapsCompatible(b.getCapabilityProvider())) {
+		if (!source.areCapsCompatible(target.getCapabilityProvider())) {
 			callbackInfo.cancel();
 		}
 	}

patchwork-capabilities/src/main/java/net/minecraftforge/common/capabilities/CapabilityDispatcher.java

@@ -75,11 +75,11 @@ public CapabilityDispatcher(Map<Identifier, ICapabilityProvider> providers, List
 		}
 
 		for (Map.Entry<Identifier, ICapabilityProvider> entry : providers.entrySet()) {
-			ICapabilityProvider prov = entry.getValue();
-			capabilities.add(prov);
+			ICapabilityProvider provider = entry.getValue();
+			capabilities.add(provider);
 
-			if (prov instanceof INBTSerializable) {
-				writers.add((INBTSerializable<Tag>) prov);
+			if (provider instanceof INBTSerializable) {
+				writers.add((INBTSerializable<Tag>) provider);
 				names.add(entry.getKey().toString());
 			}
 		}

patchwork-capabilities/src/main/java/net/minecraftforge/common/capabilities/CapabilityProvider.java

@@ -47,7 +47,12 @@ public final void gatherCapabilities() {
 	public void gatherCapabilities(@Nullable ICapabilityProvider parent) {
 		AttachCapabilitiesEvent<B> event = new AttachCapabilitiesEvent<>(baseClass, (B) this);
 		MinecraftForge.EVENT_BUS.post(event);
-		capabilities = !event.getCapabilities().isEmpty() || parent != null ? new CapabilityDispatcher(event.getCapabilities(), event.getListeners(), parent) : null;
+
+		if (!event.getCapabilities().isEmpty() || parent != null) {
+			capabilities = new CapabilityDispatcher(event.getCapabilities(), event.getListeners(), parent);
+		} else {
+			capabilities = null;
+		}
 	}
 
 	public final @Nullable CapabilityDispatcher getCapabilities() {

patchwork-capabilities/src/main/java/net/minecraftforge/event/AttachCapabilitiesEvent.java

@@ -63,7 +63,7 @@ public T getObject() {
 	}
 
 	/**
-	 * Adds a {@link net.minecraftforge.common.capabilities.Capability} to be attached to this object.
+	 * Adds a {@link net.minecraftforge.common.capabilities.ICapabilityProvider capability provider} to be attached to this object.
 	 * Keys MUST be unique, it is suggested that you set the domain to your mod ID.
 	 * If the capability is an instance of {@link net.minecraftforge.common.util.INBTSerializable}, this key will be used when serializing this capability.
 	 *