From cb49400d680894d69534b0b4cd10b085de325e2a Mon Sep 17 00:00:00 2001
From: nagachika <nagachika@ruby-lang.org>
Date: Sat, 17 May 2025 15:57:05 +0900
Subject: [PATCH] merge revision(s) 7793b59c8d2a13c124fe276e11723db23facce04:
 [Backport #21331]

	[Bug #21331] Prohibit hash modification during stlike loop
---
 hash.c                 | 20 ++++++++++++++++++--
 test/ruby/test_hash.rb |  8 ++++++++
 version.h              |  2 +-
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/hash.c b/hash.c
index 18b0fdb6dc..ec7bd2c9ac 100644
--- a/hash.c
+++ b/hash.c
@@ -1391,6 +1391,7 @@ hash_foreach_ensure(VALUE hash)
     return 0;
 }
 
+/* This does not manage iteration level */
 int
 rb_hash_stlike_foreach(VALUE hash, st_foreach_callback_func *func, st_data_t arg)
 {
@@ -1402,6 +1403,7 @@ rb_hash_stlike_foreach(VALUE hash, st_foreach_callback_func *func, st_data_t arg
     }
 }
 
+/* This does not manage iteration level */
 int
 rb_hash_stlike_foreach_with_replace(VALUE hash, st_foreach_check_callback_func *func, st_update_callback_func *replace, st_data_t arg)
 {
@@ -3326,6 +3328,20 @@ transform_values_foreach_replace(st_data_t *key, st_data_t *value, st_data_t arg
     return ST_CONTINUE;
 }
 
+static VALUE
+transform_values_call(VALUE hash)
+{
+    rb_hash_stlike_foreach_with_replace(hash, transform_values_foreach_func, transform_values_foreach_replace, hash);
+    return hash;
+}
+
+static void
+transform_values(VALUE hash)
+{
+    hash_iter_lev_inc(hash);
+    rb_ensure(transform_values_call, hash, hash_foreach_ensure, hash);
+}
+
 /*
  *  call-seq:
  *    hash.transform_values {|value| ... } -> new_hash
@@ -3356,7 +3372,7 @@ rb_hash_transform_values(VALUE hash)
     SET_DEFAULT(result, Qnil);
 
     if (!RHASH_EMPTY_P(hash)) {
-        rb_hash_stlike_foreach_with_replace(result, transform_values_foreach_func, transform_values_foreach_replace, result);
+        transform_values(result);
         compact_after_delete(result);
     }
 
@@ -3385,7 +3401,7 @@ rb_hash_transform_values_bang(VALUE hash)
     rb_hash_modify_check(hash);
 
     if (!RHASH_TABLE_EMPTY_P(hash)) {
-        rb_hash_stlike_foreach_with_replace(hash, transform_values_foreach_func, transform_values_foreach_replace, hash);
+        transform_values(hash);
     }
 
     return hash;
diff --git a/test/ruby/test_hash.rb b/test/ruby/test_hash.rb
index 2d36556953..49aa30b735 100644
--- a/test/ruby/test_hash.rb
+++ b/test/ruby/test_hash.rb
@@ -1816,6 +1816,14 @@ class TestHash < Test::Unit::TestCase
       end
     end
     assert_equal(@cls[a: 2, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8, i: 9, j: 10], x)
+
+    x = (1..1337).to_h {|k| [k, k]}
+    assert_raise_with_message(RuntimeError, /rehash during iteration/) do
+      x.transform_values! {|v|
+        x.rehash if v == 1337
+        v * 2
+      }
+    end
   end
 
   def hrec h, n, &b
diff --git a/version.h b/version.h
index 1fd402aa40..ffac97951d 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 148
+#define RUBY_PATCHLEVEL 149
 
 #include "ruby/version.h"
 #include "ruby/internal/abi.h"