From 1284bf655c2fdc862b23f206b646dcd1a9aab843 Mon Sep 17 00:00:00 2001
From: Charles Oliver Nutter <headius@headius.com>
Date: Thu, 20 Jun 2024 02:23:54 -0500
Subject: [PATCH] Copy instance vars in Binding#dup

---
 core/src/main/java/org/jruby/RubyBinding.java | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/org/jruby/RubyBinding.java b/core/src/main/java/org/jruby/RubyBinding.java
index ce36b1944ca..864c3fe805a 100644
--- a/core/src/main/java/org/jruby/RubyBinding.java
+++ b/core/src/main/java/org/jruby/RubyBinding.java
@@ -108,7 +108,11 @@ public IRubyObject initialize(ThreadContext context) {
 
     @JRubyMethod
     public IRubyObject dup(ThreadContext context) {
-        return newBinding(context.runtime, binding.dup(context));
+        RubyBinding newBinding = newBinding(context.runtime, binding.dup(context));
+
+        copyInstanceVariablesInto(newBinding);
+
+        return newBinding;
     }
 
     @JRubyMethod(name = "initialize_copy", visibility = Visibility.PRIVATE)