Fix #14600. Correct reference handling and naming of ImportError convenience function

Python/dynload_win.c

@@ -254,9 +254,9 @@ dl_funcptr _PyImport_GetDynLoadWindows(const char *shortname,
                         theLength));
             }
             if (message != NULL) {
-                PyErr_SetFromImportErrorWithNameAndPath(message,
-                                        PyUnicode_FromString(shortname),
-                                        pathname);
+                PyErr_SetImportError(message, PyUnicode_FromString(shortname),
+                                     pathname);
+                Py_DECREF(message);
             }
             return NULL;
         } else {

Python/errors.c

@@ -586,50 +586,43 @@ PyObject *PyErr_SetFromWindowsErrWithUnicodeFilename(
 #endif /* MS_WINDOWS */
 
 PyObject *
-PyErr_SetExcWithArgsKwargs(PyObject *exc, PyObject *args, PyObject *kwargs)
+PyErr_SetImportError(PyObject *msg, PyObject *name, PyObject *path)
 {
-    PyObject *val;
+    PyObject *args, *kwargs, *error;
+
+    args = PyTuple_New(1);
+    if (args == NULL)
+        return NULL;
+
+    kwargs = PyDict_New();
+    if (args == NULL)
+        return NULL;
+
+    if (name == NULL)
+        name = Py_None;
+
+    if (path == NULL)
+        path = Py_None;
+
+    Py_INCREF(msg);
+    PyTuple_SetItem(args, 0, msg);
+    PyDict_SetItemString(kwargs, "name", name);
+    PyDict_SetItemString(kwargs, "path", path);
 
     /* args must at least be an empty tuple */
     if (args == NULL)
         args = PyTuple_New(0);
 
-    val = PyObject_Call(exc, args, kwargs);
-    if (val != NULL) {
-        PyErr_SetObject((PyObject *) Py_TYPE(val), val);
-        Py_DECREF(val);
+    error = PyObject_Call(PyExc_ImportError, args, kwargs);
+    if (error!= NULL) {
+        PyErr_SetObject((PyObject *) Py_TYPE(error), error);
+        Py_DECREF(error);
     }
 
-    return NULL;
-}
-
-PyObject *
-PyErr_SetFromImportErrorWithNameAndPath(PyObject *msg,
-                                        PyObject *name, PyObject *path)
-{
-    PyObject *args = PyTuple_New(1);
-    PyObject *kwargs = PyDict_New();
-    PyObject *result;
-
-    if (path == NULL)
-        path = Py_None;
-
-    PyTuple_SetItem(args, 0, msg);
-    PyDict_SetItemString(kwargs, "name", name);
-    PyDict_SetItemString(kwargs, "path", path);
-
-    result = PyErr_SetExcWithArgsKwargs(PyExc_ImportError, args, kwargs);
-
     Py_DECREF(args);
     Py_DECREF(kwargs);
 
-    return result;
-}
-
-PyObject *
-PyErr_SetFromImportErrorWithName(PyObject *msg, PyObject *name)
-{
-    return PyErr_SetFromImportErrorWithNameAndPath(msg, name, NULL);
+    return NULL;
 }
 
 void

Python/import.c

@@ -2460,7 +2460,8 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *given_globals,
         PyObject *msg = PyUnicode_FromFormat("import of %R halted; "
                                              "None in sys.modules", abs_name);
         if (msg != NULL) {
-            PyErr_SetFromImportErrorWithName(msg, abs_name);
+            PyErr_SetImportError(msg, abs_name, NULL);
+            Py_DECREF(msg);
         }
         mod = NULL;
         goto error_with_unlock;