From bcc71ef194690c767396f5d0b3ef6c784efeca1c Mon Sep 17 00:00:00 2001
From: Charles Oliver Nutter <headius@headius.com>
Date: Thu, 20 Jun 2024 02:27:42 -0500
Subject: [PATCH] Eliminate remaining uses of getInstanceVariableList

---
 .../main/java/org/jruby/BasicObjectStub.java   | 18 +++++++++++-------
 .../main/java/org/jruby/RubyBasicObject.java   | 15 ++++++++++-----
 .../runtime/builtin/InstanceVariables.java     |  5 +++++
 3 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/core/src/main/java/org/jruby/BasicObjectStub.java b/core/src/main/java/org/jruby/BasicObjectStub.java
index ba16732c24c..609e4cf0573 100644
--- a/core/src/main/java/org/jruby/BasicObjectStub.java
+++ b/core/src/main/java/org/jruby/BasicObjectStub.java
@@ -30,6 +30,7 @@
 
 import java.util.Collections;
 import java.util.List;
+import java.util.function.BiConsumer;
 
 import org.jruby.runtime.Helpers;
 import org.jruby.runtime.Block;
@@ -259,13 +260,16 @@ public static IRubyObject inspect(IRubyObject self) {
      */
     private static StringBuilder inspectObj(IRubyObject self, StringBuilder part) {
         ThreadContext context = getRuntime(self).getCurrentContext();
-        String sep = "";
-
-        for (Variable<IRubyObject> ivar : getInstanceVariables(self).getInstanceVariableList()) {
-            part.append(sep).append(' ').append(ivar.getName()).append('=');
-            part.append(invokedynamic(context, ivar.getValue(), INSPECT));
-            sep = ",";
-        }
+        getInstanceVariables(self).forEachInstanceVariable(new BiConsumer<>() {
+            String sep = "";
+
+            @Override
+            public void accept(String name, IRubyObject value) {
+                part.append(sep).append(' ').append(name).append('=');
+                part.append(invokedynamic(context, value, INSPECT));
+                sep = ",";
+            }
+        });
         part.append('>');
         return part;
     }
diff --git a/core/src/main/java/org/jruby/RubyBasicObject.java b/core/src/main/java/org/jruby/RubyBasicObject.java
index c903227a6ae..386a37e2bf5 100644
--- a/core/src/main/java/org/jruby/RubyBasicObject.java
+++ b/core/src/main/java/org/jruby/RubyBasicObject.java
@@ -50,6 +50,7 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.BiConsumer;
 
 import org.jruby.anno.JRubyMethod;
 import org.jruby.common.IRubyWarnings.ID;
@@ -1579,11 +1580,7 @@ public List<String> getInstanceVariableNameList() {
      */
     @Override
     public void copyInstanceVariablesInto(final InstanceVariables other) {
-        for (Variable<IRubyObject> var : getInstanceVariableList()) {
-            synchronized (this) {
-                other.setInstanceVariable(var.getName(), var.getValue());
-            }
-        }
+        forEachInstanceVariable(other::setInstanceVariable);
     }
 
     /**
@@ -1602,6 +1599,14 @@ public final void ensureInstanceVariablesSettable() {
         }
     }
 
+    public void forEachInstanceVariable(BiConsumer<String, IRubyObject> accessor) {
+        metaClass.getVariableAccessorsForRead().forEach((name, var) -> {
+            final Object value = var.get(this);
+            if (!(value instanceof IRubyObject rubyObject) || !IdUtil.isInstanceVariable(name)) return;
+            accessor.accept(name, rubyObject);
+        });
+    }
+
     private void raiseFrozenError() throws RaiseException {
         if (this instanceof RubyModule) {
             throw getRuntime().newFrozenError("class/module ", this);
diff --git a/core/src/main/java/org/jruby/runtime/builtin/InstanceVariables.java b/core/src/main/java/org/jruby/runtime/builtin/InstanceVariables.java
index 98da02e5028..f51e355c744 100644
--- a/core/src/main/java/org/jruby/runtime/builtin/InstanceVariables.java
+++ b/core/src/main/java/org/jruby/runtime/builtin/InstanceVariables.java
@@ -6,6 +6,7 @@
 package org.jruby.runtime.builtin;
 
 import java.util.List;
+import java.util.function.BiConsumer;
 
 /**
  * Interface that represents the instance variable aspect of Ruby
@@ -74,4 +75,8 @@ public interface InstanceVariables {
      * Copies all instance variables from the given object into the receiver
      */
     void copyInstanceVariablesInto(InstanceVariables other);
+
+    default void forEachInstanceVariable(BiConsumer<String, IRubyObject> accessor) {
+        getInstanceVariableList().forEach((var) -> accessor.accept(var.getName(), var.getValue()));
+    }
 }