From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
Date: Sat, 26 Feb 2022 13:27:31 -0700
Subject: [PATCH] Add debug for invalid GameProfiles on skull blocks/items

Improves the error message for placed in world skull blocks by default,
also adds 'Paper.debugInvalidSkullProfiles' system property which can be
set to 'true' for extra debug info (trace of updateGameprofile caller).

diff --git a/src/main/java/net/minecraft/world/level/block/entity/SkullBlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/SkullBlockEntity.java
index 91fb6678214d5f23b33d5d3b65a29fdfbb003c58..e4d4dec63260c7b3ec3ed841a1e509eb67e66fb2 100644
--- a/src/main/java/net/minecraft/world/level/block/entity/SkullBlockEntity.java
+++ b/src/main/java/net/minecraft/world/level/block/entity/SkullBlockEntity.java
@@ -131,13 +131,28 @@ public class SkullBlockEntity extends BlockEntity {
         updateGameprofile(this.owner, (owner) -> {
             this.owner = owner;
             this.setChanged();
+            // Paper start
+        }, () -> {
+            final @Nullable Level level = this.getLevel();
+            return "SkullBlockEntity at " + this.getBlockPos() + (level == null ? "" : (" in level: " + level.dimension().location()));
+            // Paper end
         });
     }
 
     public static void updateGameprofile(@Nullable GameProfile owner, Consumer<GameProfile> callback) {
+        // Paper start
+        updateGameprofile(owner, callback, null);
+    }
+
+    private static final boolean DEBUG_INVALID_SKULL_PROFILES = Boolean.getBoolean("Paper.debugInvalidSkullProfiles");
+
+    public static void updateGameprofile(@Nullable GameProfile owner, Consumer<GameProfile> callback, final @Nullable java.util.function.Supplier<String> debugInfo) {
         if (owner != null && !StringUtil.isNullOrEmpty(owner.getName()) && (!owner.isComplete() || !owner.getProperties().containsKey("textures")) && profileCache != null && sessionService != null) {
+            final @Nullable Throwable trace = DEBUG_INVALID_SKULL_PROFILES ? new Throwable("updateGameprofile caller debug trace") : null;
             profileCache.getAsync(owner.getName(), (profile) -> {
                 Util.PROFILE_EXECUTOR.execute(() -> { // Paper - not a good idea to use BLOCKING OPERATIONS on the worldgen executor
+                    try {
+                    // Paper end
                     Util.ifElse(profile, (profilex) -> {
                         Property property = Iterables.getFirst(profilex.getProperties().get("textures"), (Property)null);
                         if (property == null) {
@@ -154,6 +169,20 @@ public class SkullBlockEntity extends BlockEntity {
                             callback.accept(owner);
                         });
                     });
+                    // Paper start
+                    } catch (final Exception ex) {
+                        if (trace != null) {
+                            ex.addSuppressed(trace);
+                        }
+                        final String ownerMessage = "Original profile: '" + owner + "'";
+                        final String debugMessage = " Run with -DPaper.debugInvalidSkullProfiles=true for further debug information.";
+                        final String message = ownerMessage + (trace == null ? debugMessage : "");
+                        if (debugInfo == null) {
+                            throw new RuntimeException(message, ex);
+                        }
+                        throw new RuntimeException(debugInfo.get() + " " + message, ex);
+                    }
+                    // Paper end
                 });
             });
         } else {