From f3f73cf1614a05fe1ef388dbf32be99b714d200c Mon Sep 17 00:00:00 2001
From: Tom-TBT <tom.boissonnet@hhu.de>
Date: Tue, 3 Feb 2026 15:07:11 +0100
Subject: [PATCH] ensure user -as-default only accepts a single provided group
 and always sets it as new default group

---
 src/omero/plugins/user.py | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/src/omero/plugins/user.py b/src/omero/plugins/user.py
index 7b0790d42..76322f184 100755
--- a/src/omero/plugins/user.py
+++ b/src/omero/plugins/user.py
@@ -93,7 +93,7 @@ def _configure(self, parser):
             help="Include all users, including deactivated accounts")
 
         joingroup = parser.add(sub, self.joingroup,
-                               "Join one or more groups")
+                               "Join one or more groups and set default group")
         self.add_id_name_arguments(
             joingroup, "user. Default to the current user")
         group = self.add_group_arguments(joingroup, " to join")
@@ -102,7 +102,9 @@ def _configure(self, parser):
             help="Join the group(s) as an owner")
         group.add_argument(
             "--as-default", action="store_true", default=False,
-            help="Sets the group as the user's default group")
+            help="Sets the group as the user's default group. "
+                 "Requires a single group. Can be used to change "
+                 "default group even if already a member.")
 
         leavegroup = parser.add(
             sub, self.leavegroup, "Leave one or more groups")
@@ -346,20 +348,17 @@ def joingroup(self, args):
 
         uid, username = self.parse_userid(a, args)
         [gid, groups] = self.list_groups(a, args, use_context=False)
-        groups = self.filter_groups(groups, uid, args.as_owner, True)
-        # The list `groups` has members removed by filter_groups if the uid
-        # is already a member, so counting them here.
-        number_of_groups_passed = len(groups)
 
-        # so doing this logic before that group list filtering.
         if args.as_default:
-            # check if there's only one group defined
-            if number_of_groups_passed == 1:
+            # Check group count BEFORE filtering
+            # Otherwise we can't tell if multiple groups were passed
+            # for setting default group.
+            if len(groups) == 1:
                 # If that's the case, set that to be the default group
                 # which will happen in the rest of the function.
                 pass
             else:
-                if number_of_groups_passed > 1:
+                if len(groups) > 1:
                     # Message to user that we can only
                     # set the default group if only one group
                     # is supplied as an argument.
@@ -368,16 +367,23 @@ def joingroup(self, args):
                     # Exit the function making no changes.
                     return None
 
-        # Performing the count and funtion exit above, so we don't even hit this
-        # if we don't need to, since it would print statements about group
-        # membership.
+        if args.as_default:
+            # Store the group to be set as default as filter_groups
+            # will remove it from the list if the user is already a member.
+            default_group = groups[0]
+
+        groups = self.filter_groups(groups, uid, args.as_owner, True)
         for group in groups:
             if args.as_owner:
                 self.addownersbyid(a, group, [uid])
             else:
                 self.addusersbyid(a, group, [uid])
-            if args.as_default:
-                self.set_users_default_group_by_user_id(a, group, [uid])
+
+        if args.as_default:
+            # Here, we know only one group is being processed.
+            # Even if user was already a member of the group,
+            # we still want to set it as the default group.
+            self.set_users_default_group_by_user_id(a, default_group, [uid])
 
     def leavegroup(self, args):
         c = self.ctx.conn(args)