From 9d1cfc1358487d66897ba386a5e05a920ee5e6f8 Mon Sep 17 00:00:00 2001
From: Kumar Aditya <kumaraditya@python.org>
Date: Tue, 11 Nov 2025 20:02:32 +0530
Subject: [PATCH] gh-132657: optimize `PySet_Contains` for `frozenset`
 (GH-141183) (cherry picked from commit
 7211a34fe1d9704935342af8c9b46725629f2d97)

Co-authored-by: Kumar Aditya <kumaraditya@python.org>
---
 Objects/setobject.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Objects/setobject.c b/Objects/setobject.c
index 83004e57b66c20..81eeafb82d1886 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -2731,7 +2731,9 @@ PySet_Contains(PyObject *anyset, PyObject *key)
         PyErr_BadInternalCall();
         return -1;
     }
-
+    if (PyFrozenSet_CheckExact(anyset)) {
+        return set_contains_key((PySetObject *)anyset, key);
+    }
     int rv;
     Py_BEGIN_CRITICAL_SECTION(anyset);
     rv = set_contains_key((PySetObject *)anyset, key);