Fix game crashing when modded entities are present (#6364)

patches/minecraft/net/minecraft/client/renderer/entity/EntityRendererManager.java.patch

@@ -1,6 +1,23 @@
 --- a/net/minecraft/client/renderer/entity/EntityRendererManager.java
 +++ b/net/minecraft/client/renderer/entity/EntityRendererManager.java
-@@ -445,4 +445,8 @@
+@@ -183,13 +183,15 @@
+       this.field_178637_m = new PlayerRenderer(this);
+       this.field_178636_l.put("default", this.field_178637_m);
+       this.field_178636_l.put("slim", new PlayerRenderer(this, true));
++   }
+ 
++   //FORGE: Validate the existence of a renderer for each entity type after modded entity renderers have been added
++   public void validateRendererExistence() {
+       for(EntityType<?> entitytype : Registry.field_212629_r) {
+          if (entitytype != EntityType.field_200729_aH && !this.field_78729_o.containsKey(entitytype)) {
+             throw new IllegalStateException("No renderer registered for " + Registry.field_212629_r.func_177774_c(entitytype));
+          }
+       }
+-
+    }
+ 
+    public <T extends Entity> EntityRenderer<? super T> func_78713_a(T p_78713_1_) {
+@@ -445,4 +447,8 @@
     public FontRenderer func_78716_a() {
        return this.field_78736_p;
     }

src/main/java/net/minecraftforge/fml/client/registry/RenderingRegistry.java

@@ -47,6 +47,7 @@ public class RenderingRegistry
     public static void loadEntityRenderers(EntityRendererManager manager)
     {
         INSTANCE.entityRenderers.forEach((key, value) -> register(manager, key, value));
+        manager.validateRendererExistence();
     }
 
     @SuppressWarnings("unchecked")