When owner leaves, shared activity does not always go away on his own view (link-local)

[erikos]

Steps to reproduce:

- A: Share activity

- B: Join

- B: Leave activity

---> both neighborhood views are updated correctly (buddy leaves)

- A: Stop shared activity

---> activity goes not away from A's neighborhood view, but goes away from B's

---

- A: share another activity

- B: join

---> on A the old shared activity goes away

[erikos]

I tracked this down to the following:

 http://git.sugarlabs.org/projects/sugar-presence-service/repos/mainline/blobs/sucrose-0.84/src/activity.py#line1192

When 'A' leaves 'A' and 'B' are still in self._claimed_buddies. self_buddies only contains buddy 'A'. That means that new_buddies will contain 'B' when calling self._add_buddies(new_buddies). When we then try to remove buddy 'A' the disappeared signal is never called because the list of buddies is not empty (B has been added again).

 http://git.sugarlabs.org/projects/sugar-presence-service/repos/mainline/blobs/sucrose-0.84/src/activity.py#line784

[erikos]

This is only an issue on link local. When using a jabber server for establishing the connection self._claimed_buddies does only contain the buddy of machine A and hence the activity will disappear gracefully.

[erikos]

Downstream bug:  http://dev.laptop.org/ticket/10308

[erikos]

I have compared with the behavior on gabble:

When the initiator leaves old_buddies is empty and new_buddies contains both buddies. Just because remove_buddies is called first with the old_buddies as arguments we remove the activity since there are no more buddies.

 http://git.sugarlabs.org/projects/sugar-presence-service/repos/mainline/blobs/sucrose-0.84/src/activity.py#line1192

[erikos]

 http://git.sugarlabs.org/projects/sugar-presence-service/repos/mainline/blobs/sucrose-0.84/src/activity.py#line1198

Hmm, it gets even more interesting from my logs on gabble we actually send the 'disappeared' signal since the old_buddies set is empty. This removes the activity from the neighborhood view. But then, we add again the buddies (which are still in claimed_buddies) remove them and then close the channel (this is in _text_channel_closed_cb).