user_groups: Add get_recursive_strict_subgroups function.

This commit adds get_recursive_strict_subgroups function
which returns all the subgroups but not includes the user
group passed to the function.

We also update the test to check subgroups of named user
groups using the get_recursive_strict_subgroups function.
This is fine as we already test the get_recursive_subgroups
function.

zerver/lib/user_groups.py

@@ -328,6 +328,18 @@ def get_recursive_subgroups(user_group: UserGroup) -> QuerySet[UserGroup]:
     return cte.join(UserGroup, id=cte.col.group_id).with_cte(cte)
 
 
+def get_recursive_strict_subgroups(user_group: UserGroup) -> QuerySet[UserGroup]:
+    # Same as get_recursive_subgroups but does not include the
+    # user_group passed.
+    direct_subgroup_ids = user_group.direct_subgroups.all().values("id")
+    cte = With.recursive(
+        lambda cte: UserGroup.objects.filter(id__in=direct_subgroup_ids)
+        .values(group_id=F("id"))
+        .union(cte.join(UserGroup, direct_supergroups=cte.col.group_id).values(group_id=F("id")))
+    )
+    return cte.join(UserGroup, id=cte.col.group_id).with_cte(cte)
+
+
 def get_recursive_group_members(user_group: UserGroup) -> QuerySet[UserProfile]:
     return UserProfile.objects.filter(direct_groups__in=get_recursive_subgroups(user_group))
 
@@ -365,11 +377,7 @@ def get_subgroup_ids(user_group: UserGroup, *, direct_subgroup_only: bool = Fals
     if direct_subgroup_only:
         subgroup_ids = user_group.direct_subgroups.all().values_list("id", flat=True)
     else:
-        subgroup_ids = (
-            get_recursive_subgroups(user_group)
-            .exclude(id=user_group.id)
-            .values_list("id", flat=True)
-        )
+        subgroup_ids = get_recursive_strict_subgroups(user_group).values_list("id", flat=True)
 
     return list(subgroup_ids)
 

zerver/tests/test_user_groups.py

@@ -25,6 +25,7 @@ from zerver.lib.user_groups import (
     get_direct_user_groups,
     get_recursive_group_members,
     get_recursive_membership_groups,
+    get_recursive_strict_subgroups,
     get_recursive_subgroups,
     get_subgroup_ids,
     get_user_group_member_ids,
@@ -121,6 +122,13 @@ class UserGroupTestCase(ZulipTestCase):
             [leadership_group, staff_group, everyone_group],
         )
 
+        self.assertCountEqual(list(get_recursive_strict_subgroups(leadership_group)), [])
+        self.assertCountEqual(list(get_recursive_strict_subgroups(staff_group)), [leadership_group])
+        self.assertCountEqual(
+            list(get_recursive_strict_subgroups(everyone_group)),
+            [leadership_group, staff_group],
+        )
+
         self.assertCountEqual(list(get_recursive_group_members(leadership_group)), [desdemona])
         self.assertCountEqual(list(get_recursive_group_members(staff_group)), [desdemona, iago])
         self.assertCountEqual(
@@ -162,35 +170,32 @@ class UserGroupTestCase(ZulipTestCase):
             is_system_group=True,
         )
 
-        self.assertCountEqual(list(get_recursive_subgroups(owners_group)), [owners_group])
+        self.assertCountEqual(list(get_recursive_strict_subgroups(owners_group)), [])
+        self.assertCountEqual(list(get_recursive_strict_subgroups(admins_group)), [owners_group])
         self.assertCountEqual(
-            list(get_recursive_subgroups(admins_group)), [owners_group, admins_group]
+            list(get_recursive_strict_subgroups(moderators_group)),
+            [owners_group, admins_group],
         )
         self.assertCountEqual(
-            list(get_recursive_subgroups(moderators_group)),
+            list(get_recursive_strict_subgroups(full_members_group)),
             [owners_group, admins_group, moderators_group],
         )
         self.assertCountEqual(
-            list(get_recursive_subgroups(full_members_group)),
+            list(get_recursive_strict_subgroups(members_group)),
             [owners_group, admins_group, moderators_group, full_members_group],
         )
         self.assertCountEqual(
-            list(get_recursive_subgroups(members_group)),
-            [owners_group, admins_group, moderators_group, full_members_group, members_group],
-        )
-        self.assertCountEqual(
-            list(get_recursive_subgroups(everyone_group)),
+            list(get_recursive_strict_subgroups(everyone_group)),
             [
                 owners_group,
                 admins_group,
                 moderators_group,
                 full_members_group,
                 members_group,
-                everyone_group,
             ],
         )
         self.assertCountEqual(
-            list(get_recursive_subgroups(everyone_on_internet_group)),
+            list(get_recursive_strict_subgroups(everyone_on_internet_group)),
             [
                 owners_group,
                 admins_group,
@@ -198,7 +203,6 @@ class UserGroupTestCase(ZulipTestCase):
                 full_members_group,
                 members_group,
                 everyone_group,
-                everyone_on_internet_group,
             ],
         )