Lifetime of wl_seat objects (was Re: [PATCH wayland-protocols 1/2] Introduce wp_relative_pointer) interface

[Peter Hutterer]

On Fri, Nov 20, 2015 at 02:59:50PM +0800, Jonas Ådahl wrote:
[...]
> > > +    <request name="destroy" type="destructor">
> > > +      <description summary="release the relative pointer object"/>
> > > +    </request>
> > > +
> > 
> > Should we add something about pairing this with wl_seat capabilities here?
> > Just looking at this protocol doesn't make it clear what happens if the
> > compositor drops the wl_pointer. Right now it's implicit, when the
> > capability drops you need to destroy the wl_pointer and the
> > wl_relative_pointer; spelling this out is useful.
> 
> It's not even spelled out what happens to a wl_pointer when the seat
> looses the pointer capability. For example right now a client running on
> weston can ignore any capability lost event and just keep whatever
> objects it ever created and they'll work again. So, I think we should
> first make it clear there, then follow up here and do the same.

urgh. so I guess we need to encode this in the protocol then, a
wl_pointer/keyboard/touch object once obtained is re-used in the seat when
the capability comes back. it's terrible IMO, but if we've been shipping
this behaviour there isn't much about this we can do now without breaking
existing clients. I don't mind writing the documentation patches, but I'd
like to have general consensus about it.

Cheers,
   Peter