Make the singleplayer F3 screen threadsafe by disallowing level access

CHANGELOG.md

@@ -12,10 +12,11 @@ confirming the issue without worldthreader.
 
 ## Fixes:
 
-- Ticking time, weather and sleeping players order ensured by updating in overworld before updating in the other
-  dimension
-- Using the server console accessed the overworld
-- Non-world threads could incorrectly request exclusive world access during world tick
+- Fix ticking time, weather and sleeping players order by updating them in the overworld before updating them in the
+  other dimension
+- Fix non-world threads being able to request exclusive world access during world tick incorrectly
+- Fix F3 debug screen unsafely accessing the server world in singleplayer by not showing that information
+- Fix Server console unsafely accessing the overworld to get the spawn position by delaying the access
 
 ## Known issues:
 

DESIGN.md

@@ -52,4 +52,9 @@ needed.
 - DimensionDataStorage is per-dimension in vanilla, but maps and some others are tied to overworld
   - Crafter block scaling or locking a map in the nether or end takes exclusive world access
 - Network connections have a non-threadsafe integer counter for tracking network statistics
-  - Currently still non-threadsafe in worldthreader, leading to possibly wrong packet counts being displayed
+  - Currently still non-threadsafe in worldthreader, leading to possibly wrong packet counts being displayed
+
+## Vanilla issues fixed
+
+- Fix F3 debug screen unsafely accessing the server world in singleplayer by not showing that information
+- Fix Server console unsafely accessing the overworld to get the spawn position by delaying the access

src/main/java/no2/worldthreader/mixin/threading_compatibility/DebugScreenOverlayMixin.java

@@ -0,0 +1,51 @@
+package no2.worldthreader.mixin.threading_compatibility;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.gui.components.DebugScreenOverlay;
+import net.minecraft.client.server.IntegratedServer;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.level.Level;
+import org.jetbrains.annotations.Nullable;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Overwrite;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+@Mixin(DebugScreenOverlay.class)
+public class DebugScreenOverlayMixin {
+
+    @Shadow
+    @Final
+    private Minecraft minecraft;
+
+    /**
+     * @author 2No2Name
+     * @reason That's not threadsafe. So don't do it.
+     */
+    @Overwrite
+    @Nullable
+    private ServerLevel getServerLevel() {
+        return null;
+    }
+
+    /**
+     * @author 2No2Name
+     * @reason That's not threadsafe. So don't do it.
+     */
+    @Overwrite
+    private Level getLevel() {
+        return this.minecraft.level;
+    }
+
+    @Redirect(
+            method = {"getGameInformation()Ljava/util/List;", "drawGameInformation(Lnet/minecraft/client/gui/GuiGraphics;)V"},
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/client/Minecraft;getSingleplayerServer()Lnet/minecraft/client/server/IntegratedServer;")
+    )
+    private IntegratedServer avoidOffthreadAccess(Minecraft instance) {
+        return null;
+    }
+}

src/main/resources/worldthreader.mixins.json

@@ -72,6 +72,7 @@
     "threadsafe_scoreboard.teams.ServerScoreboardMixin"
   ],
   "client": [
+    "threading_compatibility.DebugScreenOverlayMixin"
   ],
   "injectors": {
     "defaultRequire": 1