pythoncapi
diff --git a/‎Lib/test/test_import/__init__.py‎
Lines changed: 12 additions & 0 deletions b/‎Lib/test/test_import/__init__.py‎
Lines changed: 12 additions & 0 deletions
diff --git a/‎Misc/NEWS.d/next/Core and Builtins/2017-09-16-22-49-16.bpo-31492.RtyteL.rst‎
Lines changed: 3 additions & 0 deletions b/‎Misc/NEWS.d/next/Core and Builtins/2017-09-16-22-49-16.bpo-31492.RtyteL.rst‎
Lines changed: 3 additions & 0 deletions
diff --git a/‎Objects/moduleobject.c‎
Lines changed: 1 addition & 4 deletions b/‎Objects/moduleobject.c‎
Lines changed: 1 addition & 4 deletions
diff --git a/‎Python/ceval.c‎
Lines changed: 4 additions & 0 deletions b/‎Python/ceval.c‎
Lines changed: 4 additions & 0 deletions
@@ -400,6 +400,18 @@ def __getattr__(self, _):
         self.assertEqual(str(cm.exception),
             "cannot import name 'does_not_exist' from '<unknown module name>' (unknown location)")
 
+    @cpython_only
+    def test_issue31492(self):
+        # There shouldn't be an assertion failure in case of failing to import
+        # from a module with a bad __name__ attribute, or in case of failing
+        # to access an attribute of such a module.
+        with swap_attr(os, '__name__', None):
+            with self.assertRaises(ImportError):
+                from os import does_not_exist
+
+            with self.assertRaises(AttributeError):
+                os.does_not_exist
+
     def test_concurrency(self):
         sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'data'))
         try:
 
@@ -0,0 +1,3 @@
+Fix assertion failures in case of failing to import from a module with a bad
+``__name__`` attribute, and in case of failing to access an attribute of such
+a module. Patch by Oren Milman.
@@ -687,14 +687,11 @@ module_getattro(PyModuleObject *m, PyObject *name)
     if (m->md_dict) {
         _Py_IDENTIFIER(__name__);
         mod_name = _PyDict_GetItemId(m->md_dict, &PyId___name__);
-        if (mod_name) {
+        if (mod_name && PyUnicode_Check(mod_name)) {
             PyErr_Format(PyExc_AttributeError,
                         "module '%U' has no attribute '%U'", mod_name, name);
             return NULL;
         }
-        else if (PyErr_Occurred()) {
-            PyErr_Clear();
-        }
     }
     PyErr_Format(PyExc_AttributeError,
                 "module has no attribute '%U'", name);
 
@@ -4930,6 +4930,10 @@ import_from(PyObject *v, PyObject *name)
     if (pkgname == NULL) {
         goto error;
     }
+    if (!PyUnicode_Check(pkgname)) {
+        Py_CLEAR(pkgname);
+        goto error;
+    }
     fullmodname = PyUnicode_FromFormat("%U.%U", pkgname, name);
     if (fullmodname == NULL) {
         Py_DECREF(pkgname);
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+Fix assertion failures in case of failing to import from a module with a bad`
	`2`	+``__name__`` attribute, and in case of failing to access an attribute of such
	`3`	`+a module. Patch by Oren Milman.`