Prevent errors when extra_fields are null.

contentcuration/contentcuration/models.py

@@ -1886,7 +1886,7 @@ def mark_complete(self):  # noqa C901
                     except completion_criteria.ValidationError:
                         errors.append("Mastery criterion is defined but is invalid")
             else:
-                criterion = self.extra_fields.get("options", {}).get("completion_criteria", {})
+                criterion = self.extra_fields and self.extra_fields.get("options", {}).get("completion_criteria", {})
                 if criterion:
                     try:
                         completion_criteria.validate(criterion, kind=self.kind_id)

contentcuration/contentcuration/tests/test_contentnodes.py

@@ -1171,3 +1171,21 @@ def test_create_exercise_bad_new_extra_fields(self):
         AssessmentItem.objects.create(contentnode=new_obj, question="This is a question", answers="[{\"correct\": true, \"text\": \"answer\"}]")
         new_obj.mark_complete()
         self.assertFalse(new_obj.complete)
+
+    def test_create_video_null_extra_fields(self):
+        licenses = list(License.objects.filter(copyright_holder_required=False, is_custom=False).values_list("pk", flat=True))
+        channel = testdata.channel()
+        new_obj = ContentNode(
+            title="yes",
+            kind_id=content_kinds.VIDEO,
+            parent=channel.main_tree,
+            license_id=licenses[0],
+            copyright_holder="Some person",
+            extra_fields=None,
+        )
+        new_obj.save()
+        File.objects.create(contentnode=new_obj, preset_id=format_presets.VIDEO_HIGH_RES, checksum=uuid.uuid4().hex)
+        try:
+            new_obj.mark_complete()
+        except AttributeError:
+            self.fail("Null extra_fields not handled")