Limit recursive block updates to prevent stack overflow crashes (#424)

* Limit recursive block updates to prevent stack overflow crashes

* Review comments

src/main/java/com/mitchej123/hodgepodge/config/FixesConfig.java

@@ -352,6 +352,12 @@ public class FixesConfig {
     @Config.RequiresMcRestart
     public static boolean fixCaseCommands;
 
+    @Config.Comment("Limit the number of recursive cascading block updates during world generation to prevent stack overflow crashes, set to -1 to disable the limit.")
+    @Config.RangeInt(min = -1)
+    @Config.DefaultInt(256) // A stack overflow with water updates happens somewhere above 300 updates with default Java
+                            // settings
+    public static int limitRecursiveBlockUpdateDepth;
+
     // affecting multiple mods
 
     @Config.Comment("Remove old/stale/outdated update checks.")

src/main/java/com/mitchej123/hodgepodge/mixins/Mixins.java

@@ -421,6 +421,12 @@ public enum Mixins {
             .setPhase(Phase.EARLY).setSide(Side.BOTH).addTargetedMod(TargetedMod.VANILLA)
             .addMixinClasses("minecraft.MixinCommandHandler_CommandFix").setApplyIf(() -> FixesConfig.fixCaseCommands)),
 
+    LIMIT_RECURSIVE_BLOCK_UPDATE_DEPTH(new Builder(
+            "Limit the number of recursive cascading block updates during world generation to prevent stack overflow crashes")
+                    .setPhase(Phase.EARLY).setSide(Side.BOTH).addTargetedMod(TargetedMod.VANILLA)
+                    .addMixinClasses("minecraft.MixinWorldServer_LimitUpdateRecursion")
+                    .setApplyIf(() -> FixesConfig.limitRecursiveBlockUpdateDepth >= 0)),
+
     // Ic2 adjustments
     IC2_UNPROTECTED_GET_BLOCK_FIX(new Builder("IC2 Kinetic Fix").setPhase(Phase.EARLY).setSide(Side.BOTH)
             .addMixinClasses("ic2.MixinIc2WaterKinetic").setApplyIf(() -> FixesConfig.fixIc2UnprotectedGetBlock)

src/main/java/com/mitchej123/hodgepodge/mixins/early/minecraft/MixinWorldServer_LimitUpdateRecursion.java

@@ -0,0 +1,46 @@
+package com.mitchej123.hodgepodge.mixins.early.minecraft;
+
+import net.minecraft.block.Block;
+import net.minecraft.world.WorldServer;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import com.mitchej123.hodgepodge.Common;
+import com.mitchej123.hodgepodge.config.FixesConfig;
+
+@Mixin(WorldServer.class)
+public class MixinWorldServer_LimitUpdateRecursion {
+
+    @Unique
+    private int hodgepodge$currentBlockUpdateRecursiveCalls = 0;
+
+    @Inject(method = "scheduleBlockUpdateWithPriority", at = @At("HEAD"), cancellable = true)
+    private void hodgepodge$incrementBlockUpdateRecursionCounter(int x, int y, int z, Block block, int tickDelay,
+            int priority, CallbackInfo ci) {
+        if (hodgepodge$currentBlockUpdateRecursiveCalls >= FixesConfig.limitRecursiveBlockUpdateDepth) {
+            final StackOverflowError error = new StackOverflowError(
+                    String.format(
+                            "Too many recursive block updates (%d) at world %d, block %s (%d, %d, %d) - aborting further block updates",
+                            hodgepodge$currentBlockUpdateRecursiveCalls,
+                            ((WorldServer) (Object) this).provider.dimensionId,
+                            block,
+                            x,
+                            y,
+                            z));
+            Common.log.error(error.getMessage(), error);
+            ci.cancel();
+            return;
+        }
+        hodgepodge$currentBlockUpdateRecursiveCalls++;
+    }
+
+    @Inject(method = "scheduleBlockUpdateWithPriority", at = @At("RETURN"))
+    private void hodgepodge$decrementBlockUpdateRecursionCounter(int x, int y, int z, Block block, int tickDelay,
+            int priority, CallbackInfo ci) {
+        hodgepodge$currentBlockUpdateRecursiveCalls = Math.max(0, hodgepodge$currentBlockUpdateRecursiveCalls - 1);
+    }
+}