build: validate gcFreeChunkSerializer output in tests

Author: ishland

c2me-rewrites-chunk-serializer/src/main/java/com/ishland/c2me/rewrites/chunk_serializer/TheMod.java

@@ -4,6 +4,7 @@
 import com.ishland.c2me.base.common.registry.SerializerAccess;
 import com.ishland.c2me.rewrites.chunk_serializer.common.ChunkDataSerializer;
 import com.ishland.c2me.rewrites.chunk_serializer.common.NbtWriter;
+import com.ishland.c2me.rewrites.chunk_serializer.common.utils.ValidationUtils;
 import net.minecraft.nbt.NbtElement;
 
 public class TheMod implements net.fabricmc.api.ModInitializer {
@@ -17,6 +18,7 @@ public void onInitialize() {
                 nbtWriter.finishCompound();
                 final byte[] data = nbtWriter.toByteArray();
                 nbtWriter.release();
+                ValidationUtils.validateNbt(data);
                 return Either.right(data);
             });
         }

c2me-rewrites-chunk-serializer/src/main/java/com/ishland/c2me/rewrites/chunk_serializer/common/utils/ValidationUtils.java

@@ -0,0 +1,30 @@
+package com.ishland.c2me.rewrites.chunk_serializer.common.utils;
+
+import net.minecraft.nbt.NbtCompound;
+import net.minecraft.nbt.NbtIo;
+
+import java.io.ByteArrayInputStream;
+import java.io.DataInputStream;
+
+public class ValidationUtils {
+
+    private static final boolean VALIDATION_ENABLED = Boolean.getBoolean("c2me.gcFreeChunkSerializer.validateNbt");
+
+    static {
+        if (VALIDATION_ENABLED) {
+            System.out.println("NBT validation for gcFreeChunkSerializer is enabled. This *will* impact performance.");
+        }
+    }
+
+    public static void validateNbt(byte[] bytes) {
+        if (!VALIDATION_ENABLED) {
+            return;
+        }
+        try (final var in = new DataInputStream(new ByteArrayInputStream(bytes))) {
+            NbtCompound read = NbtIo.readCompound(in);
+        } catch (Throwable e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+}

c2me-rewrites-chunk-serializer/src/main/java/com/ishland/c2me/rewrites/chunk_serializer/mixin/MixinThreadedAnvilChunkStorage.java

@@ -6,6 +6,7 @@
 import com.ishland.c2me.base.mixin.access.IVersionedChunkStorage;
 import com.ishland.c2me.rewrites.chunk_serializer.common.ChunkDataSerializer;
 import com.ishland.c2me.rewrites.chunk_serializer.common.NbtWriter;
+import com.ishland.c2me.rewrites.chunk_serializer.common.utils.ValidationUtils;
 import com.mojang.datafixers.DataFixer;
 import net.minecraft.nbt.NbtElement;
 import net.minecraft.server.world.ChunkHolder;
@@ -100,7 +101,9 @@ private boolean save(Chunk chunk) {
                     nbtWriter.start(NbtElement.COMPOUND_TYPE);
                     ChunkDataSerializer.write(chunkSerializer, nbtWriter);
                     nbtWriter.finishCompound();
-                    return nbtWriter.toByteArray();
+                    byte[] byteArray = nbtWriter.toByteArray();
+                    ValidationUtils.validateNbt(byteArray);
+                    return byteArray;
                 } finally {
                     nbtWriter.release();
                 }

tests/c2me-test/build.gradle

@@ -13,6 +13,7 @@ loom {
                     "-Dc2me.base.config.override.ioSystem.gcFreeChunkSerializer=true",
                     "-Dc2me.base.config.override.vanillaWorldGenOptimizations.useDensityFunctionCompiler=true",
                     "-Dc2me.base.config.override.vanillaWorldGenOptimizations.nativeAcceleration.enabled=true",
+                    "-Dc2me.gcFreeChunkSerializer.validateNbt=true",
                     "-Dcom.ishland.c2me.mixin.doAudit=true"
             if (System.getenv("GITHUB_WORKFLOW") != null) {
                 if (System.getenv("RUNNER_OS").equals("macOS")) {