Re: [Pyst-users] a comment...

[Matthew N. <mni...@di...>]

On Fri, 2008-04-18 at 23:09 +0200, Jan Müller wrote:
> hi,
> 
> triggered by the recent mailing list activities, i just began to scan 
> the code of manager.py, and i found this:
> 
>     def event_dispatch(self):
>         """This thread is responsible fore dispatching events"""
> 
>         # loop dispatching events
>         while self._running.isSet():
>             # get/wait for an event
>             ev = self._event_queue.get()
> 
>             # if we got None as an event, we are finished
>             if not ev:
>                 break
> 
>             # dispatch our events
> 
>             # first build a list of the functions to execute
>             callbacks = self._event_callbacks.get(ev.name, [])
>             callbacks.extend(self._event_callbacks.get('*', []))  # <- !!!
>
>             # now execute the functions
>             for callback in callbacks:
>                if callback(ev, self):
>                   break
> 
> what happens here is that the '*' callback handlers are explicitly added 
> to the (mutable) list of ev.name handlers.
> i haven't tried it but this should lead to problems when unsubscribing a 
> '*' handler since it still remains an
> ev.name handler. i suggest a list addition to prevent manipulation of 
> the list of ev.name handlers:
> 
> [...]
>             # first build a list of the functions to execute
>             callbacks = self._event_callbacks.get(ev.name, []) + 
> self._event_callbacks.get('*', [])
> [...]

This is a potential problem.  In theory, if I understand what you are
saying correctly, each time an event is handled the '*' callback list
should get appended to the ev.name list.

-- 
Matthew Nicholson
Digium