fix

Author: corona10

Lib/test/test_opcache.py

@@ -609,7 +609,7 @@ def assert_races_do_not_crash(
             for writer in writers:
                 writer.join()
 
-    @requires_specialization_ft
+    @requires_specialization
     def test_binary_subscr_getitem(self):
         def get_items():
             class C:
@@ -1245,6 +1245,14 @@ def f(o, n):
         f(test_obj, 1)
         self.assertEqual(test_obj.b, 0)
 
+# gh-115999: BINARY_SUBSCR_GETITEM will only cache __getitem__ methods that
+# are deferred. We only defer functions defined at the top-level.
+class CGetItem:
+    def __init__(self, val):
+        self.val = val
+    def __getitem__(self, item):
+        return self.val
+
 
 class TestSpecializer(TestBase):
 
@@ -1521,12 +1529,7 @@ def binary_subscr_str_int():
         self.assert_no_opcode(binary_subscr_str_int, "BINARY_SUBSCR")
 
         def binary_subscr_getitems():
-            class C:
-                def __init__(self, val):
-                    self.val = val
-                def __getitem__(self, item):
-                    return self.val
-            items = [C(i) for i in range(100)]
+            items = [CGetItem(i) for i in range(100)]
             for i in range(100):
                 self.assertEqual(items[i][i], i)
 

Objects/typeobject.c

@@ -5693,17 +5693,19 @@ _PyType_CacheInitForSpecialization(PyHeapTypeObject *type, PyObject *init,
 }
 
 int
-_PyType_CacheGetItemForSpecialization(PyHeapTypeObject *ht, PyObject *descriptor, uint32_t version)
+_PyType_CacheGetItemForSpecialization(PyHeapTypeObject *ht, PyObject *descriptor, uint32_t tp_version)
 {
-    if (!descriptor || !version) {
+    if (!descriptor || !tp_version) {
         return 0;
     }
     int can_cache;
     BEGIN_TYPE_LOCK();
+    can_cache = ((PyTypeObject*)ht)->tp_version_tag == tp_version;
     // This pointer is invalidated by PyType_Modified (see the comment on
     // struct _specialization_cache):
     PyFunctionObject *func = (PyFunctionObject *)descriptor;
-    can_cache = _PyFunction_GetVersionForCurrentState(func) == version;
+    uint32_t version = _PyFunction_GetVersionForCurrentState(func);
+    can_cache = _PyFunction_IsVersionValid(version);
 #ifdef Py_GIL_DISABLED
     can_cache = can_cache && _PyObject_HasDeferredRefcount(descriptor);
 #endif

Python/specialize.c

@@ -1797,8 +1797,8 @@ _Py_Specialize_BinarySubscr(
             Py_DECREF(descriptor);
             goto success;
         }
-        Py_DECREF(descriptor);
     }
+    Py_XDECREF(descriptor);
     SPECIALIZATION_FAIL(BINARY_SUBSCR,
                         binary_subscr_fail_kind(container_type, sub));
 fail: