Fix bad url parameter in error response with invalid redirect_uri

Author: jleclanche

oauth2_provider/views/mixins.py

@@ -159,11 +159,11 @@ def error_response(self, error, **kwargs):
         oauthlib_error = error.oauthlib_error
 
         redirect_uri = oauthlib_error.redirect_uri or ""
-        separator = '&' if '?' in redirect_uri else '?'
+        separator = "&" if "?" in redirect_uri else "?"
 
         error_response = {
-            'error': oauthlib_error,
-            'url': "{0}{1}{2}".format(oauthlib_error.redirect_uri, separator, oauthlib_error.urlencoded)
+            "error": oauthlib_error,
+            "url": redirect_uri + separator + oauthlib_error.urlencoded,
         }
         error_response.update(kwargs)
 

tests/test_authorization_code.py

@@ -117,6 +117,10 @@ def test_pre_auth_invalid_client(self):
 
         response = self.client.get(url)
         self.assertEqual(response.status_code, 400)
+        self.assertEqual(
+            response.context_data["url"],
+            "?error=invalid_request&error_description=Invalid+client_id+parameter+value."
+        )
 
     def test_pre_auth_valid_client(self):
         """