Use the existing user object in the case where a user is making changes to their own preferences

openedx/core/djangoapps/user_api/preferences/api.py

@@ -310,7 +310,13 @@ def _get_authorized_user(requesting_user, username=None, allow_staff=False):
     If username is not provided, requesting_user.username is assumed.
     """
     if username is None:
-        username = requesting_user.username
+        # If the user is one that has already been stored to the database, use that
+        if requesting_user.pk:
+            return requesting_user
+        else:
+            # Otherwise, treat this as a request against a separate user
+            username = requesting_user.username
+
     try:
         existing_user = User.objects.get(username=username)
     except ObjectDoesNotExist:

openedx/core/djangoapps/user_api/preferences/tests/test_api.py

@@ -53,9 +53,8 @@ class TestPreferenceAPI(CacheIsolationTestCase):
         super(TestPreferenceAPI, self).setUp()
         self.user = UserFactory.create(password=self.password)
         self.different_user = UserFactory.create(password=self.password)
-        self.staff_user = UserFactory(is_staff=True, password=self.password)
-        self.no_such_user = UserFactory.create(password=self.password)
-        self.no_such_user.username = "no_such_user"
+        self.staff_user = UserFactory.create(is_staff=True, password=self.password)
+        self.no_such_user = UserFactory.build(password=self.password, username="no_such_user")
         self.test_preference_key = "test_key"
         self.test_preference_value = "test_value"
         set_user_preference(self.user, self.test_preference_key, self.test_preference_value)