[PATCH wayland] server: Make serial number 0 mean invalid

[Daniel Stone]

Hi,

On 8 October 2015 at 08:27, Jonas Ådahl <jadahl at gmail.com> wrote:
> On Mon, Oct 05, 2015 at 12:04:49PM -0500, Derek Foreman wrote:
>> There are cases in weston where it would be quite nice to have a
>> sentinel value to use instead of having to have a bool for "this serial
>> number is legit" too.
>
> Even though probably unlikely, for clients unaware of a possible 0 == no
> serial, this would mean that they would suddenly start to be killed when
> when they before worked just fine.
>
>>
>> > In cases where we have two behaviors for serial-aware and
>> > non-serial-aware operations, I would rather have two different client
>> > requests.
>
> This would be my preference as well. Partly because the semantics of a
> request with a serial and one without will probably behave differently,
> and partly because the existing places where you pass a serial has
> mentioning of any "non-serial" or "invalid serial" situations and we'd
> now just add a bunch of undefined behaviour.
>
> Is it really a big deal to have to multiple requests that do things
> differently?

Let's try to solve this empirically, then - which optional-serial
requests do we have apart from present/needs-attention here, and what
does/would the difference look like semantically?

Cheers,
Daniel