Comment 21 for bug 91925

But all messages are shared by all tasks.
So, it seems to me that all unassigned and incomplete tasks of a bug where last comment is older than N weeks for a project which the bug manager is Malone should be put in state 'Expired' with a message stating that 'any message added to this bug will automatically reopen it (make invalid)'. Of course this message must not in itself reopen the bug :-). And we should never change status of a task on a project not managed by Malone.

Ideally N (number of weeks before expiring a bug) would depend on the project.
I don't know if a reopened bug should be allowed to expire again.