From a976792832887ee2ae1380ab0e2244067126f017 Mon Sep 17 00:00:00 2001
From: nagachika <nagachika@ruby-lang.org>
Date: Sun, 29 Jun 2025 12:27:54 +0900
Subject: [PATCH] merge revision(s) 2e7e78cd590d20aa9d41422e96302f3edd73f623:
 [Backport #21440]

	[Bug #21440] Stop caching member list in frozen Data/Struct class
---
 struct.c                 | 3 ++-
 test/ruby/test_data.rb   | 6 ++++++
 test/ruby/test_struct.rb | 6 ++++++
 version.h                | 2 +-
 4 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/struct.c b/struct.c
index c54dc12a04..23420d5e8c 100644
--- a/struct.c
+++ b/struct.c
@@ -52,7 +52,8 @@ struct_ivar_get(VALUE c, ID id)
         RUBY_ASSERT(RB_TYPE_P(c, T_CLASS));
         ivar = rb_attr_get(c, id);
         if (!NIL_P(ivar)) {
-            return rb_ivar_set(orig, id, ivar);
+            if (!OBJ_FROZEN(orig)) rb_ivar_set(orig, id, ivar);
+            return ivar;
         }
     }
 }
diff --git a/test/ruby/test_data.rb b/test/ruby/test_data.rb
index bb38f8ec91..dd698fdcc4 100644
--- a/test/ruby/test_data.rb
+++ b/test/ruby/test_data.rb
@@ -280,4 +280,10 @@ class TestData < Test::Unit::TestCase
     assert_not_same(test, loaded)
     assert_predicate(loaded, :frozen?)
   end
+
+  def test_frozen_subclass
+    test = Class.new(Data.define(:a)).freeze.new(a: 0)
+    assert_kind_of(Data, test)
+    assert_equal([:a], test.members)
+  end
 end
diff --git a/test/ruby/test_struct.rb b/test/ruby/test_struct.rb
index 3d727adf04..e6fd6af8ec 100644
--- a/test/ruby/test_struct.rb
+++ b/test/ruby/test_struct.rb
@@ -548,6 +548,12 @@ module TestStruct
     CODE
   end
 
+  def test_frozen_subclass
+    test = Class.new(@Struct.new(:a)).freeze.new(a: 0)
+    assert_kind_of(@Struct, test)
+    assert_equal([:a], test.members)
+  end
+
   class TopStruct < Test::Unit::TestCase
     include TestStruct
 
diff --git a/version.h b/version.h
index ca7065b653..9aec743969 100644
--- a/version.h
+++ b/version.h
@@ -11,7 +11,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 8
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 161
+#define RUBY_PATCHLEVEL 162
 
 #include "ruby/version.h"
 #include "ruby/internal/abi.h"