Improve compatibility of ID desync fix, and add Roadrunner support

src/main/java/org/embeddedt/modernfix/ModernFixClient.java

@@ -1,6 +1,7 @@
 package org.embeddedt.modernfix;
 
 import com.mojang.datafixers.util.Pair;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.screens.ConnectScreen;
 import net.minecraft.client.gui.screens.TitleScreen;
@@ -105,7 +106,19 @@ public class ModernFixClient {
      *
      * This is to ensure we can perform ID fixup on already constructed managers.
      */
-    public static Set<SynchedEntityData> allEntityDatas = Collections.newSetFromMap(new WeakHashMap<>());
+    public static final Set<SynchedEntityData> allEntityDatas = Collections.newSetFromMap(new WeakHashMap<>());
+
+    private static final Field entriesArrayField;
+    static {
+        Field field;
+        try {
+            field = SynchedEntityData.class.getDeclaredField("entriesArray");
+            field.setAccessible(true);
+        } catch(ReflectiveOperationException e) {
+            field = null;
+        }
+        entriesArrayField = field;
+    }
 
     /**
      * Extremely hacky method to detect and correct mismatched entity data parameter IDs on the client and server.
@@ -140,12 +153,28 @@ public class ModernFixClient {
                 if(fixNeeded) {
                     dataEntries = new ArrayList<>(allEntityDatas);
                     for(SynchedEntityData manager : dataEntries) {
-                        Map<Integer, SynchedEntityData.DataItem<?>> fixedMap = new HashMap<>();
+                        Int2ObjectOpenHashMap<SynchedEntityData.DataItem<?>> fixedMap = new Int2ObjectOpenHashMap<>();
                         List<SynchedEntityData.DataItem<?>> items = new ArrayList<>(manager.itemsById.values());
                         for(SynchedEntityData.DataItem<?> item : items) {
                             fixedMap.put(item.getAccessor().id, item);
                         }
-                        manager.itemsById = fixedMap;
+                        manager.lock.writeLock().lock();
+                        try {
+                            manager.itemsById.replaceAll((id, parameter) -> fixedMap.get((int)id));
+                            if(entriesArrayField != null) {
+                                try {
+                                    SynchedEntityData.DataItem<?>[] dataArray = new SynchedEntityData.DataItem[items.size()];
+                                    for(int i = 0; i < dataArray.length; i++) {
+                                        dataArray[i] = fixedMap.get(i);
+                                    }
+                                    entriesArrayField.set(manager, dataArray);
+                                } catch(ReflectiveOperationException e) {
+                                    ModernFix.LOGGER.error(e);
+                                }
+                            }
+                        } finally {
+                            manager.lock.writeLock().unlock();
+                        }
                     }
                 }
                 allEntityDatas.clear();

src/main/java/org/embeddedt/modernfix/mixin/bugfix/mc218112/SynchedEntityDataMixin.java

@@ -1,34 +0,0 @@
-package org.embeddedt.modernfix.mixin.bugfix.mc218112;
-
-import net.minecraft.network.syncher.EntityDataAccessor;
-import net.minecraft.network.syncher.SynchedEntityData;
-import org.spongepowered.asm.mixin.Final;
-import org.spongepowered.asm.mixin.Mixin;
-import org.spongepowered.asm.mixin.Shadow;
-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.LocalCapture;
-
-import java.util.Map;
-import java.util.concurrent.locks.ReadWriteLock;
-
-@Mixin(SynchedEntityData.class)
-public class SynchedEntityDataMixin {
-    @Shadow @Final private Map<Integer, SynchedEntityData.DataItem<?>> itemsById;
-
-    @Shadow @Final private ReadWriteLock lock;
-
-    @Shadow private boolean isEmpty;
-
-    @Inject(method = "createDataItem", at = @At(value = "INVOKE", target = "Ljava/util/Map;put(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"), cancellable = true, locals = LocalCapture.CAPTURE_FAILHARD)
-    private <T> void putWithLock(EntityDataAccessor<T> key, T value, CallbackInfo ci, SynchedEntityData.DataItem<T> item) {
-        ci.cancel();
-        try {
-            this.itemsById.put(key.getId(), item);
-            this.isEmpty = false;
-        } finally {
-            this.lock.writeLock().unlock();
-        }
-    }
-}

src/main/resources/META-INF/accesstransformer.cfg

@@ -10,4 +10,5 @@ public net.minecraft.util.concurrent.ThreadTaskExecutor func_213160_bf()V # runA
 public net.minecraft.server.MinecraftServer field_211151_aa # nextTickTime
 public net.minecraft.client.Minecraft field_213277_ad # progressListener
 public-f net.minecraft.network.datasync.DataParameter field_187157_a # id
-public-f net.minecraft.network.datasync.EntityDataManager field_187234_c # itemsById
+public-f net.minecraft.network.datasync.EntityDataManager field_187234_c # itemsById
+public-f net.minecraft.network.datasync.EntityDataManager field_187235_d # lock

src/main/resources/modernfix.mixins.json

@@ -53,7 +53,6 @@
     "perf.fast_registry_validation.ForgeRegistryMixin",
     "perf.cache_strongholds.ChunkGeneratorMixin",
     "perf.cache_upgraded_structures.StructureManagerMixin",
-    "bugfix.mc218112.SynchedEntityDataMixin",
     "perf.cache_strongholds.ServerLevelMixin"
   ],
   "client": [