Avoid synchronizing layer list in LivingEntityRenderer

Author: embeddedt

src/main/java/org/embeddedt/modernfix/common/mixin/safety/LivingEntityRendererMixin.java

@@ -1,28 +1,34 @@
 package org.embeddedt.modernfix.common.mixin.safety;
 
+import com.llamalad7.mixinextras.injector.wrapmethod.WrapMethod;
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.model.EntityModel;
 import net.minecraft.client.renderer.entity.LivingEntityRenderer;
 import net.minecraft.client.renderer.entity.layers.RenderLayer;
+import net.minecraft.world.entity.Entity;
+import org.embeddedt.modernfix.ModernFix;
 import org.embeddedt.modernfix.annotation.ClientOnlyMixin;
-import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
-import org.spongepowered.asm.mixin.Mutable;
 import org.spongepowered.asm.mixin.Shadow;
-import org.spongepowered.asm.mixin.injection.At;
-import org.spongepowered.asm.mixin.injection.Inject;
-import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
-
-import java.util.Collections;
-import java.util.List;
 
 @Mixin(LivingEntityRenderer.class)
 @ClientOnlyMixin
-public class LivingEntityRendererMixin {
-    @Shadow @Final @Mutable
-    protected List<RenderLayer<?, ?>> layers;
+public abstract class LivingEntityRendererMixin<T extends Entity, M extends EntityModel<T>> {
+    @Shadow
+    public abstract boolean addLayer(RenderLayer<T, M> layer);
 
-    @Inject(method = "<init>", at = @At("RETURN"))
-    private void synchronizeLayerList(CallbackInfo ci) {
-        /* allows buggy mods to call addLayer concurrently, order is not deterministic but can't fix that */
-        this.layers = Collections.synchronizedList(layers);
+    /**
+     * @author embeddedt
+     * @reason avoid CMEs from buggy mods calling addLayer on wrong thread
+     */
+    @WrapMethod(method = "addLayer")
+    private boolean handleOffThreadLayerAdd(RenderLayer<T, M> layer, Operation<Boolean> original) {
+        if (!Minecraft.getInstance().isSameThread()) {
+            ModernFix.LOGGER.error("LivingEntityRenderer.addLayer called on wrong thread", new Exception());
+            Minecraft.getInstance().tell(() -> this.addLayer(layer));
+            return true;
+        }
+        return original.call(layer);
     }
 }