Ensure CTM's metadataCache is thread-safe

forge/src/main/java/org/embeddedt/modernfix/forge/mixin/bugfix/ctm_resourceutil_cme/ResourceUtilMixin.java

@@ -0,0 +1,35 @@
+package org.embeddedt.modernfix.forge.mixin.bugfix.ctm_resourceutil_cme;
+
+import org.embeddedt.modernfix.annotation.ClientOnlyMixin;
+import org.embeddedt.modernfix.annotation.RequiresMod;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Mutable;
+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 team.chisel.ctm.client.util.ResourceUtil;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.concurrent.ConcurrentMap;
+
+@Mixin(ResourceUtil.class)
+@RequiresMod("ctm")
+@ClientOnlyMixin
+@SuppressWarnings({"rawtypes", "unchecked"})
+public class ResourceUtilMixin {
+    @Shadow @Final @Mutable
+    private static Map metadataCache;
+
+    /**
+     * @author embeddedt
+     * @reason quick fix to prevent rare CMEs
+     */
+    @Inject(method = "<clinit>", at = @At("RETURN"))
+    private static void synchronizeMetadataCache(CallbackInfo ci) {
+        if(!(metadataCache instanceof ConcurrentMap))
+            metadataCache = Collections.synchronizedMap(metadataCache);
+    }
+}