From cf3e9d1e0c8b45274125ac69b330344d0b9ce1f5 Mon Sep 17 00:00:00 2001
From: cpw <cpw+github@weeksfamily.ca>
Date: Sun, 1 Nov 2020 19:51:56 -0500
Subject: [PATCH] actually rollback on error in registry events.

Signed-off-by: cpw <cpw+github@weeksfamily.ca>
---
 src/main/java/net/minecraftforge/registries/GameData.java | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/main/java/net/minecraftforge/registries/GameData.java b/src/main/java/net/minecraftforge/registries/GameData.java
index 507b4e6bb1..f412c88e13 100644
--- a/src/main/java/net/minecraftforge/registries/GameData.java
+++ b/src/main/java/net/minecraftforge/registries/GameData.java
@@ -374,11 +374,12 @@ public class GameData
     }
 
     public static CompletableFuture<List<Throwable>> checkForRevertToVanilla(final Executor executor, final CompletableFuture<List<Throwable>> listCompletableFuture) {
-        return listCompletableFuture.thenApplyAsync(errors -> {
-            if (!errors.isEmpty()) {
+        return listCompletableFuture.whenCompleteAsync((errors, except) -> {
+            if (except != null) {
+                LOGGER.fatal("Detected errors during registry event dispatch, rolling back to VANILLA state");
                 revertTo(RegistryManager.VANILLA, false);
+                LOGGER.fatal("Detected errors during registry event dispatch, roll back to VANILLA complete");
             }
-            return errors;
         }, executor);
     }