fix 'internal_failure' condition

google/oauth2/_client.py

@@ -104,18 +104,21 @@ def _token_endpoint_request(request, token_uri, body):
     while True:
         response = request(method="POST", url=token_uri, headers=headers, body=body)
         response_body = response.data.decode("utf-8")
+        response_data = json.loads(response_body)
 
         if response.status == http_client.OK:
             break
         else:
-            error_desc = json.loads(response_body).get("error_description") or ""
-            if error_desc == "internal_failure" and retry < 1:
+            error_desc = response_data.get("error_description") or ""
+            error_code = response_data.get("error") or ""
+            if (
+                any(e == "internal_failure" for e in (error_code, error_desc))
+                and retry < 1
+            ):
                 retry += 1
                 continue
             _handle_error_response(response_body)
 
-    response_data = json.loads(response_body)
-
     return response_data
 
 

tests/oauth2/test__client.py

@@ -123,6 +123,15 @@ def test__token_endpoint_request_internal_failure_error():
             {"error": "internal_failure", "error_description": "internal_failure"},
         )
 
+    request = make_request(
+        {"error": "internal_failure"}, status=http_client.BAD_REQUEST
+    )
+
+    with pytest.raises(exceptions.RefreshError):
+        _client._token_endpoint_request(
+            request, "http://example.com", {"error": "internal_failure"}
+        )
+
 
 def verify_request_params(request, params):
     request_body = request.call_args[1]["body"]