From: Victor Stinner <vstinner@python.org>
Date: Thu, 5 Mar 2026 11:31:29 +0000 (+0100)
Subject: gh-141510: Don't accept frozendict in PyDict_Watch() (#145529)
X-Git-Tag: v3.15.0a7~59
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0fe20fc1703c52c0b2597d70df6cad9b3e4056f0;p=thirdparty%2FPython%2Fcpython.git

gh-141510: Don't accept frozendict in PyDict_Watch() (#145529)

Don't accept frozendict in PyDict_Watch() and PyDict_Unwatch().
A frozendict cannot be modified, so it's not useful to watch for
modifications.
---

diff --git a/Lib/test/test_capi/test_watchers.py b/Lib/test/test_capi/test_watchers.py
index bef72032513d..67595e3550b0 100644
--- a/Lib/test/test_capi/test_watchers.py
+++ b/Lib/test/test_capi/test_watchers.py
@@ -176,8 +176,9 @@ class TestDictWatchers(unittest.TestCase):
 
     def test_unwatch_non_dict(self):
         with self.watcher() as wid:
-            with self.assertRaisesRegex(ValueError, r"Cannot watch non-dictionary"):
-                self.unwatch(wid, 1)
+            for wrong_type in (frozendict(), 5, [123], object()):
+                with self.assertRaisesRegex(ValueError, r"Cannot watch non-dictionary"):
+                    self.unwatch(wid, wrong_type)
 
     def test_unwatch_out_of_range_watcher_id(self):
         d = {}
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 2552216152f9..e0127f04249f 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -7912,7 +7912,7 @@ validate_watcher_id(PyInterpreterState *interp, int watcher_id)
 int
 PyDict_Watch(int watcher_id, PyObject* dict)
 {
-    if (!PyAnyDict_Check(dict)) {
+    if (!PyDict_Check(dict)) {
         PyErr_SetString(PyExc_ValueError, "Cannot watch non-dictionary");
         return -1;
     }
@@ -7927,7 +7927,7 @@ PyDict_Watch(int watcher_id, PyObject* dict)
 int
 PyDict_Unwatch(int watcher_id, PyObject* dict)
 {
-    if (!PyAnyDict_Check(dict)) {
+    if (!PyDict_Check(dict)) {
         PyErr_SetString(PyExc_ValueError, "Cannot watch non-dictionary");
         return -1;
     }