jruby · headius · Feb 3, 2026 · Jan 15, 2026 · Feb 3, 2026
diff --git a/core/src/main/java/org/jruby/runtime/invokedynamic/VariableSite.java b/core/src/main/java/org/jruby/runtime/invokedynamic/VariableSite.java
@@ -145,10 +145,10 @@ public IRubyObject ivarGet(IRubyObject self) throws Throwable {
         MethodHandle test = findStatic(VariableSite.class, "testRealClass", methodType(boolean.class, int.class, IRubyObject.class));
         test = insertArguments(test, 0, accessor.getClassId());
 
-        getValue = guardWithTest(test, getValue, fallback);
+        MethodHandle guarded = guardWithTest(test, getValue, fallback);
 
         if (Options.INVOKEDYNAMIC_LOG_BINDING.load()) LOG.info(name() + "\tget on class " + self.getMetaClass().id + " bound directly" + extractSourceInfo());
-        setTarget(getValue);
+        setTarget(guarded);
 
         return (IRubyObject)getValue.invokeExact(self);
     }
@@ -209,10 +209,10 @@ public void ivarSet(IRubyObject self, IRubyObject value) throws Throwable {
         test = insertArguments(test, 0, accessor.getClassId());
         test = dropArguments(test, 1, IRubyObject.class);
 
-        setValue = guardWithTest(test, setValue, fallback);
+        MethodHandle guarded = guardWithTest(test, setValue, fallback);
 
         if (Options.INVOKEDYNAMIC_LOG_BINDING.load()) LOG.info(name() + "\tset on class " + self.getMetaClass().id + " bound directly" + extractSourceInfo());
-        setTarget(setValue);
+        setTarget(guarded);
 
         setValue.invokeExact(self, value);
     }

diff --git a/core/src/main/java/org/jruby/runtime/ivars/FieldVariableAccessor.java b/core/src/main/java/org/jruby/runtime/ivars/FieldVariableAccessor.java
@@ -43,8 +43,8 @@
  * A variable accessor that accesses a field directly;
  */
 public class FieldVariableAccessor extends VariableAccessor {
-    private final MethodHandle getter;
-    private final MethodHandle setter;
+    protected final MethodHandle getter;
+    protected final MethodHandle setter;
 
     /**
      * Construct a new FieldVariableAccessor for the given "real" class,
@@ -64,6 +64,10 @@ public FieldVariableAccessor(RubyClass realClass, String name, int index, int cl
         this.setter = wrapSetter(setter);
     }
 
+    public FieldVariableAccessor cloneFor(RubyClass newRealClass) {
+        return new FieldVariableAccessor(newRealClass, name, index, classId, getter, setter);
+    }
+
     protected MethodHandle wrapSetter(MethodHandle setter) {
         // mix frozen check into setter
         return MethodHandles.foldArguments(setter, ENSURE_SETTABLE.asType(setter.type()));

diff --git a/core/src/main/java/org/jruby/runtime/ivars/RawFieldVariableAccessor.java b/core/src/main/java/org/jruby/runtime/ivars/RawFieldVariableAccessor.java
@@ -59,8 +59,15 @@ public class RawFieldVariableAccessor extends FieldVariableAccessor {
      * @param setter the setter handle for the field
      */
     public RawFieldVariableAccessor(RubyClass realClass, boolean unwrapInSet, Class<?> toJava, Class<?> returnType, String name, int index, int classId, MethodHandle getter, MethodHandle setter) {
-        super(realClass, name, index, classId, wrapGetter(getter, realClass, returnType), wrapSetter(setter, realClass, unwrapInSet, toJava, returnType));
+        this(realClass, name, index, classId, wrapGetter(getter, realClass, returnType), wrapSetter(setter, realClass, unwrapInSet, toJava, returnType));
+    }
+
+    private RawFieldVariableAccessor(RubyClass realClass, String name, int index, int classId, MethodHandle getter, MethodHandle setter) {
+        super(realClass, name, index, classId, getter, setter);
+    }
 
+    public RawFieldVariableAccessor cloneFor(RubyClass newRealClass) {
+        return new RawFieldVariableAccessor(newRealClass, name, index, classId, getter, setter);
     }
 
     @Override

diff --git a/core/src/main/java/org/jruby/runtime/ivars/StampedVariableAccessor.java b/core/src/main/java/org/jruby/runtime/ivars/StampedVariableAccessor.java
@@ -51,6 +51,10 @@ public StampedVariableAccessor(RubyClass realClass, String name, int index, int
         super(realClass, name, index, classId);
     }
 
+    public StampedVariableAccessor cloneFor(RubyClass newRealClass) {
+        return new StampedVariableAccessor(newRealClass, name, index, classId);
+    }
+
     /**
      * Set this variable into the given object using Unsafe to ensure
      * safe updating of the variable table.

diff --git a/core/src/main/java/org/jruby/runtime/ivars/VariableAccessor.java b/core/src/main/java/org/jruby/runtime/ivars/VariableAccessor.java
@@ -192,6 +192,10 @@ public String toString() {
         return "ivar:" + getName() + ":" + index;
     }
 
+    public VariableAccessor cloneFor(RubyClass newRealClass) {
+        throw new UnsupportedOperationException();
+    }
+
     /** a dummy accessor that will always return null */
     public static final VariableAccessor DUMMY_ACCESSOR = new VariableAccessor(null, null, -1, -1) {};
 

diff --git a/core/src/main/java/org/jruby/runtime/ivars/VariableTableManager.java b/core/src/main/java/org/jruby/runtime/ivars/VariableTableManager.java
@@ -115,7 +115,7 @@ public VariableTableManager(RubyClass realClass) {
     VariableTableManager(VariableTableManager original, RubyClass realClass) {
         synchronized (original) {
             this.realClass = realClass;
-            this.variableAccessors = copyVariableAccessors(original.variableAccessors);
+            this.variableAccessors = copyVariableAccessors(realClass, original.variableAccessors);
             this.variableNames = original.variableNames.clone();
             this.hasObjectID = original.hasObjectID;
             this.hasFFI = original.hasFFI;
@@ -283,8 +283,10 @@ VariableAccessor getVariableAccessorWithBuilder(String name, Function<Integer, V
         return ivarAccessor;
     }
 
-    private static Map<String, VariableAccessor> copyVariableAccessors(Map<String, VariableAccessor> myVariableAccessors) {
-        return new LinkedHashMap<>(myVariableAccessors);
+    private static Map<String, VariableAccessor> copyVariableAccessors(RubyClass realClass, Map<String, VariableAccessor> otherVariableAccessors) {
+        var myVariableAccessors = new LinkedHashMap<String, VariableAccessor>(otherVariableAccessors.size());
+        otherVariableAccessors.forEach((name, accessor) -> myVariableAccessors.put(name, accessor.cloneFor(realClass)));
+        return myVariableAccessors;
     }
 
     private static Map<String, VariableAccessor> copyVariableAccessors(Map<String, VariableAccessor> myVariableAccessors, String name, VariableAccessor ivarAccessor) {

diff --git a/test/mri/excludes/TestData.rb b/test/mri/excludes/TestData.rb