github: Return '' when name is None.

zerver/tests/test_auth_backends.py

@@ -358,6 +358,10 @@ class GitHubAuthBackendTest(ZulipTestCase):
         # type: () -> None
         self.assertEqual(self.backend.get_full_name(), '')
 
+    def test_full_name_with_none(self):
+        # type: () -> None
+        self.assertEqual(self.backend.get_full_name(response={'email': None}), '')
+
     def test_github_backend_do_auth_without_subdomains(self):
         # type: () -> None
         with mock.patch('social_core.backends.github.GithubOAuth2.do_auth',

zproject/backends.py

@@ -419,11 +419,20 @@ class GitHubAuthBackend(SocialAuthMixin, GithubOAuth2):
 
     def get_full_name(self, *args, **kwargs):
         # type: (*Any, **Any) -> Text
+        # In case of any error return an empty string. Name is used by
+        # the registration page to pre-populate the name field. However,
+        # if it is not supplied, our registration process will make sure
+        # that the user enters a valid name.
         try:
-            return kwargs['response']['name']
+            name = kwargs['response']['name']
         except KeyError:
+            name = ''
+
+        if name is None:
             return ''
 
+        return name
+
     def do_auth(self, *args, **kwargs):
         # type: (*Any, **Any) -> Optional[HttpResponse]
         kwargs['return_data'] = {}