Merge pull request #11010 from edx/bderusha/auto-deadlines

Fix auto set deadlines on publish

common/djangoapps/course_modes/models.py

@@ -159,7 +159,9 @@ class CourseMode(models.Model):
     @expiration_datetime.setter
     def expiration_datetime(self, new_datetime):
         """ Saves datetime to _expiration_datetime and sets the explicit flag. """
-        self.expiration_datetime_is_explicit = True
+        # Only set explicit flag if we are setting an actual date.
+        if new_datetime is not None:
+            self.expiration_datetime_is_explicit = True
         self._expiration_datetime = new_datetime
 
     @classmethod

common/djangoapps/course_modes/tests/test_models.py

@@ -421,3 +421,12 @@ class CourseModeModelTest(TestCase):
 
         self.assertFalse(verified_mode.expiration_datetime_is_explicit)
         self.assertEqual(verified_mode.expiration_datetime, now)
+
+    def test_expiration_datetime_explicitly_set_to_none(self):
+        """ Verify that setting the _expiration_date property does not set the explicit flag. """
+        verified_mode, __ = self.create_mode('verified', 'Verified Certificate')
+        self.assertFalse(verified_mode.expiration_datetime_is_explicit)
+
+        verified_mode.expiration_datetime = None
+        self.assertFalse(verified_mode.expiration_datetime_is_explicit)
+        self.assertIsNone(verified_mode.expiration_datetime)