Make sure adhoc groups have a name.

kolibri/core/auth/models.py

@@ -1512,6 +1512,15 @@ class AdHocGroup(Collection):
     class Meta:
         proxy = True
 
+    @classmethod
+    def deserialize(cls, dict_model):
+        # be defensive against blank names, set to `Ad hoc` if blank
+        name = dict_model.get("name", "") or ""
+        if len(name) == 0:
+            dict_model.update(name="Ad hoc")
+
+        return super(AdHocGroup, cls).deserialize(dict_model)
+
     def save(self, *args, **kwargs):
         if not self.parent:
             raise IntegrityError(

kolibri/core/auth/upgrade.py

@@ -16,3 +16,12 @@ def prune_empty_adhoc_groups():
     needed. This upgrade task cleans up those empty adhoc groups.
     """
     AdHocGroup.objects.filter(membership__isnull=True).delete()
+
+
+@version_upgrade(old_version="<0.15.0")
+def name_unnamed_adhoc_groups():
+    """
+    We started making adhoc groups for every lesson and quiz, even though they were not
+    needed. This upgrade task cleans up those empty adhoc groups.
+    """
+    AdHocGroup.objects.filter(name="").update(name="Ad hoc")

kolibri/core/auth/utils.py

@@ -29,7 +29,7 @@ def confirm_or_exit(message):
 
 
 def create_adhoc_group_for_learners(classroom, learners):
-    adhoc_group = AdHocGroup.objects.create(name="", parent=classroom)
+    adhoc_group = AdHocGroup.objects.create(name="Ad hoc", parent=classroom)
     for learner in learners:
         Membership.objects.create(user=learner, collection=adhoc_group)
     return adhoc_group