From: Kumar Aditya <kumaraditya@python.org>
Date: Thu, 26 Mar 2026 09:06:55 +0000 (+0530)
Subject: gh-146453: fix `_PyType_LookupByVersion` for types with fixed pre-defined version... 
X-Git-Tag: v3.15.0a8~174
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=495178ab058b35aa89b82099be80ad1ad01fa496;p=thirdparty%2FPython%2Fcpython.git

gh-146453: fix `_PyType_LookupByVersion` for types with fixed pre-defined version tags (#146454)
---

diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index 9ebfa4f33f30..1456296a1339 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -3017,6 +3017,20 @@ class TestUopsOptimization(unittest.TestCase):
         self.assertNotIn("_LOAD_ATTR_METHOD_NO_DICT", uops)
         self.assertNotIn("_LOAD_ATTR_METHOD_LAZY_DICT", uops)
 
+    def test_cached_attributes_fixed_version_tag(self):
+        def f(n):
+            c = 1
+            x = 0
+            for _ in range(n):
+                x += c.bit_length()
+            return x
+
+        res, ex = self._run_with_optimizer(f, TIER2_THRESHOLD)
+        self.assertIsNotNone(ex)
+        self.assertEqual(res, TIER2_THRESHOLD)
+        uops = get_opnames(ex)
+        self.assertNotIn("_LOAD_ATTR_METHOD_NO_DICT", uops)
+
     def test_store_fast_refcount_elimination(self):
         def foo(x):
             # Since x is known to be
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 7b4318e79fb2..66f6c3fb3c0a 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -1349,6 +1349,35 @@ _PyType_LookupByVersion(unsigned int version)
 #ifdef Py_GIL_DISABLED
     return NULL;
 #else
+    switch (version) {
+        case _Py_TYPE_VERSION_INT:
+            return &PyLong_Type;
+        case _Py_TYPE_VERSION_FLOAT:
+            return &PyFloat_Type;
+        case _Py_TYPE_VERSION_LIST:
+            return &PyList_Type;
+        case _Py_TYPE_VERSION_TUPLE:
+            return &PyTuple_Type;
+        case _Py_TYPE_VERSION_STR:
+            return &PyUnicode_Type;
+        case _Py_TYPE_VERSION_SET:
+            return &PySet_Type;
+        case _Py_TYPE_VERSION_FROZEN_SET:
+            return &PyFrozenSet_Type;
+        case _Py_TYPE_VERSION_DICT:
+            return &PyDict_Type;
+        case _Py_TYPE_VERSION_BYTEARRAY:
+            return &PyByteArray_Type;
+        case _Py_TYPE_VERSION_BYTES:
+            return &PyBytes_Type;
+        case _Py_TYPE_VERSION_COMPLEX:
+            return &PyComplex_Type;
+        case _Py_TYPE_VERSION_FROZENDICT:
+            return &PyFrozenDict_Type;
+        default:
+            break;
+    }
+
     PyInterpreterState *interp = _PyInterpreterState_GET();
     PyTypeObject **slot =
         interp->types.type_version_cache