Add off-by-default option to disable the DFU maps for flattening

src/main/java/org/embeddedt/modernfix/core/config/ModernFixEarlyConfig.java

@@ -41,6 +41,7 @@ public class ModernFixEarlyConfig {
         /* Use a simpler ArrayMap if FerriteCore is using the map intelligently anyway */
         this.addMixinRule("perf.state_definition_construct", modPresent("ferritecore"));
         this.addMixinRule("perf.cache_strongholds", true);
+        this.addMixinRule("perf.dedup_blockstate_flattening_map", false);
         this.addMixinRule("perf.cache_upgraded_structures", true);
         this.addMixinRule("perf.biome_zoomer", true);
         this.addMixinRule("perf.compress_blockstate", false);

src/main/java/org/embeddedt/modernfix/mixin/perf/dedup_blockstate_flattening_map/BlockStateDataMixin.java

@@ -0,0 +1,21 @@
+package org.embeddedt.modernfix.mixin.perf.dedup_blockstate_flattening_map;
+
+import net.minecraft.util.datafix.fixes.BlockStateData;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+@Mixin(BlockStateData.class)
+public class BlockStateDataMixin {
+    @Inject(method = {"register", "finalizeMaps"}, at = @At("HEAD"), cancellable = true)
+    private static void noFlattening(CallbackInfo ci) {
+        ci.cancel();
+    }
+
+    @Inject(method = {"upgradeBlockStateTag", "upgradeBlock(I)Ljava/lang/String;", "upgradeBlock(Ljava/lang/String;)Ljava/lang/String;", "getTag"}, at = @At("HEAD"), require = 4)
+    private static void preventCorruption(CallbackInfoReturnable<?> cir) {
+        throw new UnsupportedOperationException("Performing the Flattening is currently disabled in the ModernFix config.");
+    }
+}

src/main/java/org/embeddedt/modernfix/mixin/perf/dedup_blockstate_flattening_map/ChunkPalettedStorageFixMixin.java

@@ -0,0 +1,31 @@
+package org.embeddedt.modernfix.mixin.perf.dedup_blockstate_flattening_map;
+
+import com.mojang.serialization.Dynamic;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtOps;
+import net.minecraft.util.datafix.fixes.ChunkPalettedStorageFix;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import java.util.function.Consumer;
+
+@Mixin(ChunkPalettedStorageFix.class)
+public class ChunkPalettedStorageFixMixin {
+    @Redirect(method = "<clinit>", at = @At(value = "INVOKE", target = "Lcom/mojang/datafixers/DataFixUtils;make(Ljava/lang/Object;Ljava/util/function/Consumer;)Ljava/lang/Object;"))
+    private static Object skipMakingMap(Object o, Consumer<?> consumer) {
+        return o;
+    }
+
+    @Redirect(method = "<clinit>", at = @At(value = "INVOKE", target = "Lnet/minecraft/util/datafix/fixes/BlockStateData;getTag(I)Lcom/mojang/serialization/Dynamic;"))
+    private static Dynamic<?> getFakeAirTag(int id) {
+        return new Dynamic<>(NbtOps.INSTANCE, new CompoundTag());
+    }
+
+    @Inject(method = "fix", at = @At("HEAD"))
+    private void skipFix(CallbackInfoReturnable<Dynamic<?>> cir) {
+        throw new UnsupportedOperationException("No Flattening for you.");
+    }
+}

src/main/resources/modernfix.mixins.json

@@ -66,6 +66,8 @@
     "perf.biome_zoomer.FuzzyOffsetBiomeZoomerMixin",
     "perf.compress_blockstate.BlockStateBaseMixin",
     "perf.compress_blockstate.BlockBehaviourMixin",
+    "perf.dedup_blockstate_flattening_map.BlockStateDataMixin",
+    "perf.dedup_blockstate_flattening_map.ChunkPalettedStorageFixMixin",
     "devenv.MinecraftServerMixin"
   ],
   "client": [