From 90bc890b95479d7603e0a60ed992032a001bb6ba Mon Sep 17 00:00:00 2001
From: NotEvil <notevil@noreply.com>
Date: Tue, 14 Apr 2026 02:46:09 +0200
Subject: [PATCH] fix(D-01): synchronize reload paths and capture snapshot
 locally (RISK-001, RISK-002)

---
 .../datadriven/DataDrivenItemRegistry.java    | 39 ++++++++++++-------
 1 file changed, 25 insertions(+), 14 deletions(-)

diff --git a/src/main/java/com/tiedup/remake/v2/bondage/datadriven/DataDrivenItemRegistry.java b/src/main/java/com/tiedup/remake/v2/bondage/datadriven/DataDrivenItemRegistry.java
index 5e726e2..1c72af3 100644
--- a/src/main/java/com/tiedup/remake/v2/bondage/datadriven/DataDrivenItemRegistry.java
+++ b/src/main/java/com/tiedup/remake/v2/bondage/datadriven/DataDrivenItemRegistry.java
@@ -48,6 +48,9 @@ public final class DataDrivenItemRegistry {
      */
     private static volatile RegistrySnapshot SNAPSHOT = RegistrySnapshot.EMPTY;
 
+    /** Guards read-then-write sequences in {@link #reload} and {@link #mergeAll}. */
+    private static final Object RELOAD_LOCK = new Object();
+
     private DataDrivenItemRegistry() {}
 
     /**
@@ -59,9 +62,11 @@ public final class DataDrivenItemRegistry {
     public static void reload(
         Map<ResourceLocation, DataDrivenItemDefinition> newDefs
     ) {
-        Map<ResourceLocation, DataDrivenItemDefinition> defs =
-            Collections.unmodifiableMap(new HashMap<>(newDefs));
-        SNAPSHOT = new RegistrySnapshot(defs, buildComponentHolders(defs));
+        synchronized (RELOAD_LOCK) {
+            Map<ResourceLocation, DataDrivenItemDefinition> defs =
+                Collections.unmodifiableMap(new HashMap<>(newDefs));
+            SNAPSHOT = new RegistrySnapshot(defs, buildComponentHolders(defs));
+        }
     }
 
     /**
@@ -78,13 +83,15 @@ public final class DataDrivenItemRegistry {
     public static void mergeAll(
         Map<ResourceLocation, DataDrivenItemDefinition> newDefs
     ) {
-        Map<ResourceLocation, DataDrivenItemDefinition> merged = new HashMap<>(
-            SNAPSHOT.definitions
-        );
-        merged.putAll(newDefs);
-        Map<ResourceLocation, DataDrivenItemDefinition> defs =
-            Collections.unmodifiableMap(merged);
-        SNAPSHOT = new RegistrySnapshot(defs, buildComponentHolders(defs));
+        synchronized (RELOAD_LOCK) {
+            Map<ResourceLocation, DataDrivenItemDefinition> merged = new HashMap<>(
+                SNAPSHOT.definitions
+            );
+            merged.putAll(newDefs);
+            Map<ResourceLocation, DataDrivenItemDefinition> defs =
+                Collections.unmodifiableMap(merged);
+            SNAPSHOT = new RegistrySnapshot(defs, buildComponentHolders(defs));
+        }
     }
 
     /**
@@ -95,7 +102,8 @@ public final class DataDrivenItemRegistry {
      */
     @Nullable
     public static DataDrivenItemDefinition get(ResourceLocation id) {
-        return SNAPSHOT.definitions.get(id);
+        RegistrySnapshot snap = SNAPSHOT;
+        return snap.definitions.get(id);
     }
 
     /**
@@ -113,7 +121,8 @@ public final class DataDrivenItemRegistry {
             tag.getString(NBT_ITEM_ID)
         );
         if (id == null) return null;
-        return SNAPSHOT.definitions.get(id);
+        RegistrySnapshot snap = SNAPSHOT;
+        return snap.definitions.get(id);
     }
 
     /**
@@ -122,7 +131,8 @@ public final class DataDrivenItemRegistry {
      * @return unmodifiable collection of all definitions
      */
     public static Collection<DataDrivenItemDefinition> getAll() {
-        return SNAPSHOT.definitions.values();
+        RegistrySnapshot snap = SNAPSHOT;
+        return snap.definitions.values();
     }
 
     /**
@@ -168,7 +178,8 @@ public final class DataDrivenItemRegistry {
      */
     @Nullable
     public static ComponentHolder getComponents(ResourceLocation id) {
-        return SNAPSHOT.holders.get(id);
+        RegistrySnapshot snap = SNAPSHOT;
+        return snap.holders.get(id);
     }
 
     /**