From: Neko Asakura <neko.asakura@outlook.com>
Date: Sun, 12 Apr 2026 12:54:03 +0000 (-0400)
Subject: gh-148398: add type watcher in `_CHECK_ATTR_CLASS` (GH-148399)
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=30c698a655bafdb53db0d39426a2b5cfce3b19ca;p=thirdparty%2FPython%2Fcpython.git

gh-148398: add type watcher in `_CHECK_ATTR_CLASS` (GH-148399)
---

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-04-11-15-12-53.gh-issue-148398.g62jCA.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-04-11-15-12-53.gh-issue-148398.g62jCA.rst
new file mode 100644
index 000000000000..0a7ba0b27d97
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-04-11-15-12-53.gh-issue-148398.g62jCA.rst
@@ -0,0 +1 @@
+Fix a bug in the JIT optimizer where class attribute loads were not invalidated after type mutation.
diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index c12a4f4131bc..39dc4877af88 100644
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -226,6 +226,10 @@ dummy_func(void) {
             }
             else {
                 sym_set_const(owner, type);
+                if ((((PyTypeObject *)type)->tp_flags & Py_TPFLAGS_IMMUTABLETYPE) == 0) {
+                    PyType_Watch(TYPE_WATCHER_ID, type);
+                    _Py_BloomFilter_Add(dependencies, type);
+                }
             }
         }
     }
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index 2db2c87cb361..746653906874 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -2571,6 +2571,10 @@
                 }
                 else {
                     sym_set_const(owner, type);
+                    if ((((PyTypeObject *)type)->tp_flags & Py_TPFLAGS_IMMUTABLETYPE) == 0) {
+                        PyType_Watch(TYPE_WATCHER_ID, type);
+                        _Py_BloomFilter_Add(dependencies, type);
+                    }
                 }
             }
             break;