gh-133166: Fix missing error emission of PyType_GetModuleByDef (GH-133240)

Lib/test/test_capi/test_type.py

@@ -179,6 +179,22 @@ class TypeTests(unittest.TestCase):
             _testcapi.pytype_getbasebytoken(
                 'not a type', id(self), True, False)
 
+    def test_get_module_by_def(self):
+        heaptype = _testcapi.create_type_with_token('_testcapi.H', 0)
+        mod = _testcapi.pytype_getmodulebydef(heaptype)
+        self.assertIs(mod, _testcapi)
+
+        class H1(heaptype): pass
+        mod = _testcapi.pytype_getmodulebydef(H1)
+        self.assertIs(mod, _testcapi)
+
+        with self.assertRaises(TypeError):
+            _testcapi.pytype_getmodulebydef(int)
+
+        class H2(int): pass
+        with self.assertRaises(TypeError):
+            _testcapi.pytype_getmodulebydef(H2)
+
     def test_freeze(self):
         # test PyType_Freeze()
         type_freeze = _testcapi.type_freeze

Misc/NEWS.d/next/C_API/2025-05-01-01-02-11.gh-issue-133166.Ly9Ae2.rst

@@ -0,0 +1,2 @@
+Fix regression where :c:func:`PyType_GetModuleByDef` returns NULL without
+setting :exc:`TypeError` when a static type is passed.

Modules/_testcapi/heaptype.c

@@ -521,6 +521,13 @@ error:
     return NULL;
 }
 
+static PyObject *
+pytype_getmodulebydef(PyObject *self, PyObject *type)
+{
+    PyObject *mod = PyType_GetModuleByDef((PyTypeObject *)type, _testcapimodule);
+    return Py_XNewRef(mod);
+}
+
 
 static PyMethodDef TestMethods[] = {
     {"pytype_fromspec_meta",    pytype_fromspec_meta,            METH_O},
@@ -538,6 +545,7 @@ static PyMethodDef TestMethods[] = {
     {"create_type_with_token", create_type_with_token, METH_VARARGS},
     {"get_tp_token", get_tp_token, METH_O},
     {"pytype_getbasebytoken", pytype_getbasebytoken, METH_VARARGS},
+    {"pytype_getmodulebydef", pytype_getmodulebydef, METH_O},
     {NULL},
 };
 

Objects/typeobject.c

@@ -5399,7 +5399,7 @@ PyType_GetModuleByDef(PyTypeObject *type, PyModuleDef *def)
     if (!_PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
         // type_ready_mro() ensures that no heap type is
         // contained in a static type MRO.
-        return NULL;
+        goto error;
     }
     else {
         PyHeapTypeObject *ht = (PyHeapTypeObject*)type;
@@ -5439,13 +5439,15 @@ PyType_GetModuleByDef(PyTypeObject *type, PyModuleDef *def)
     }
     END_TYPE_LOCK();
 
-    if (res == NULL) {
-        PyErr_Format(
-            PyExc_TypeError,
-            "PyType_GetModuleByDef: No superclass of '%s' has the given module",
-            type->tp_name);
+    if (res != NULL) {
+        return res;
     }
-    return res;
+error:
+    PyErr_Format(
+        PyExc_TypeError,
+        "PyType_GetModuleByDef: No superclass of '%s' has the given module",
+        type->tp_name);
+    return NULL;
 }