Changes have been made in Git for this ticket:

merge from cvs:
[mjr] Do not remove history entries when removing user data (Bug: 8755).

http://git.horde.org/diff.php/kronolith/docs/CHANGES?rt=horde-git&r1=ecad5df422e803d1b11b19f7c02ef933d70d40a9&r2=d653cbb76fcb36a689b2df0659349894cb3b9f4d
http://git.horde.org/diff.php/kronolith/lib/Application.php?rt=horde-git&r1=a861b23f6c641b45228b9a8a2a8cf90e5013be5e&r2=d653cbb76fcb36a689b2df0659349894cb3b9f4d
http://git.horde.org/diff.php/mnemo/docs/CHANGES?rt=horde-git&r1=e3584d4c26d4ef312304e28bd26e038dbe6d50eb&r2=d653cbb76fcb36a689b2df0659349894cb3b9f4d
http://git.horde.org/diff.php/mnemo/lib/Api.php?rt=horde-git&r1=bb701dabc2661d2481fe50ad9f0955f1e736b82d&r2=d653cbb76fcb36a689b2df0659349894cb3b9f4d
http://git.horde.org/diff.php/nag/docs/CHANGES?rt=horde-git&r1=d4491e6b4e0f9ddfd81193f5bed0d914b41a994b&r2=d653cbb76fcb36a689b2df0659349894cb3b9f4d
http://git.horde.org/diff.php/nag/lib/Application.php?rt=horde-git&r1=a861b23f6c641b45228b9a8a2a8cf90e5013be5e&r2=d653cbb76fcb36a689b2df0659349894cb3b9f4d

Changes have been made in CVS for this ticket:

Be consistent in not removing history entries when removing all user data.
Still need a utility script to delete history entries over a certain 
age, but this
commit closes Bug: 8755
http://cvs.horde.org/diff.php/kronolith/lib/api.php?rt=horde&r1=1.126.2.66&r2=1.126.2.67&ty=u
http://cvs.horde.org/diff.php/mnemo/lib/api.php?rt=horde&r1=1.53.2.35&r2=1.53.2.36&ty=u
http://cvs.horde.org/diff.php/nag/lib/api.php?rt=horde&r1=1.100.10.46&r2=1.100.10.47&ty=u

Yes, I agree. It should be easy enough to create a garbage collection 
script that searches for all UIDs in the history that have been 
deleted a certain time ago and remove all entries for those.

My issue is that the user may have items he owns that has been shared 
with others. A group calendar, a group address book etc... if we 
flat-out delete everything in history, then people that have devices 
synced to those events/contacts would never see the deletion... For 
something as destructive as deleting all history entries, I feel it 
should be an explicitly triggered action.

In general the reason for logging deletion in history is for syncing - 
you have to know its gone. When deleting user data that would be true 
for shared items, but not for items owned by the user themself. I 
agree we should make it consistent, though.

Entries are made for the deletion event.

The behavior between the apps is still inconsistent though.  As the OP 
pointed out, the other groupware apps delete all the history for each 
deleted resource. In fact, in Kronolith, a history item is logged for 
the deletion, and then the entire history is removed.

My feeling is history should NOT be removed unless explicitly desired 
by the admin. Thoughts?

Changes have been made in Git for this ticket:

Log deletion of objects from _deleteAll() in Horde_History Bug: 8755

http://git.horde.org/diff.php/turba/lib/Driver/Sql.php?rt=horde-git&r1=82bb2e1d13c4b192fa4d6156e0aa1ac5597190fa&r2=87e61b393a4faa218aaa4745bbc934d75db67152

Changes have been made in CVS for this ticket:

Log deletion of each object removed in _deleteAll in Horde_History.
Bug: 8755
http://cvs.horde.org/diff.php/turba/lib/Driver/sql.php?rt=horde&r1=1.59.10.32&r2=1.59.10.33&ty=u

The analysis was correct, but the solution isn't. When calling 
_deleteAll() (no matter if through removeUserData or not), we don't 
log a delete action for the deleted contacts in the history. This 
should be fixed.

Well, that is what other applications (nag, mnemo, kronolith) are 
doing. They remove history entries for deleted items. Turba was 
neither deleting history entries nor changing their state to 'deleted' 
so I copied and adapted this code from nag. In case history data 
should not be deleted than all applications should get fixed to mark 
history entries as 'deleted'. Although I think removeUserData 
functions should really remove all user data, for example when 
deleting the user from the system.

That is because it is a history of what has happened. Removing the 
contact data removes that history.

Calling turba.removeUserData API function removes the contacts from 
the turba database but horde_histories table still contains info for 
these contacts. Attached patch deletes the remaining history data.