closes bpo-41689: Preserve text signature from tp_doc in C heap type creation. (GH-22058)

1 files changed, 12 insertions, 3 deletions

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index c66f8fc..7404075 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -3018,15 +3018,14 @@ PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)
         else if (slot->slot == Py_tp_doc) {
             /* For the docstring slot, which usually points to a static string
                literal, we need to make a copy */
-            const char *old_doc = _PyType_DocWithoutSignature(type->tp_name, slot->pfunc);
-            size_t len = strlen(old_doc)+1;
+            size_t len = strlen(slot->pfunc)+1;
             char *tp_doc = PyObject_MALLOC(len);
             if (tp_doc == NULL) {
                 type->tp_doc = NULL;
                 PyErr_NoMemory();
                 goto fail;
             }
-            memcpy(tp_doc, old_doc, len);
+            memcpy(tp_doc, slot->pfunc, len);
             type->tp_doc = tp_doc;
         }
         else if (slot->slot == Py_tp_members) {
@@ -3058,6 +3057,16 @@ PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)
         res->ht_cached_keys = _PyDict_NewKeysForClass();
     }
 
+    if (type->tp_doc) {
+        PyObject *__doc__ = PyUnicode_FromString(_PyType_DocWithoutSignature(type->tp_name, type->tp_doc));
+        if (!__doc__)
+            goto fail;
+        int ret = _PyDict_SetItemId(type->tp_dict, &PyId___doc__, __doc__);
+        Py_DECREF(__doc__);
+        if (ret < 0)
+            goto fail;
+    }
+
     if (weaklistoffset) {
         type->tp_weaklistoffset = weaklistoffset;
         if (PyDict_DelItemString((PyObject *)type->tp_dict, "__weaklistoffset__") < 0)