Issue #27186: Update os.fspath()/PyOS_FSPath() to check the return

type of __fspath__().

As part of this change, also make sure that the pure Python
implementation of os.fspath() is tested.

1 files changed, 11 insertions, 2 deletions

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 7d8249095d..df802cbc09 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -12317,12 +12317,21 @@ PyOS_FSPath(PyObject *path)
     if (NULL == func) {
         return PyErr_Format(PyExc_TypeError,
                             "expected str, bytes or os.PathLike object, "
-                            "not %S",
-                            path->ob_type);
+                            "not %.200s",
+                            Py_TYPE(path)->tp_name);
     }
 
     path_repr = PyObject_CallFunctionObjArgs(func, NULL);
     Py_DECREF(func);
+    if (!(PyUnicode_Check(path_repr) || PyBytes_Check(path_repr))) {
+        PyErr_Format(PyExc_TypeError,
+                     "expected %.200s.__fspath__() to return str or bytes, "
+                     "not %.200s", Py_TYPE(path)->tp_name,
+                     Py_TYPE(path_repr)->tp_name);
+        Py_DECREF(path_repr);
+        return NULL;
+    }
+
     return path_repr;
 }