[PATCH wayland 0/4] Untangle the symbol export duplication

[Emil Velikov]

Hi all,

On 30 August 2016 at 18:24, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> Hi all,
>
> For a while I've noticed that on mesa side we have few providers of the
> wl_drm_interface symbol and literally all our 'wayland binaries' are
> linked against both the client and server wayland libs.
>
> After having a look, it seems that:
>  - the server exposes the interface symbols for 'inheritance' purposes,
> thus other servers can build upon these primitives while designing their
> own protocols (interfaces ?).
>  - at the same time the client needs to have a reference to the
> interface symbol in order to register an instance of said interface.
>
> This means that if the "wrong" symbol gets picked at runtime and the
> client does not correctly manage older versions in its
> .registry_handle_global function (yes we have a case or two of those in
> the wild) things will end up horribly wrong.
>
> I think that a better option would have been to distinguish the two
> (call one instance or the other singleton) and let the scanner attribute
> for the name difference. Regardless of that is that it's too late to
> change things since this would lead to breaking the ABI.
>
> One way around it to update the scanner to provide newer symbols and
> annotate the old ones as deprecated. This way when/if we break the ABI
> we can untangle things. One day...
>
> Does the above sound about right - can anyone let me know if I'm loosing
> the plot ?
>
> That said, I've went ahead and removed duplication where possible - by
> folding the util symbols into libwayland-util. Please check with patch 3/4
> how compatibility with existing and new users is be preserved.
>
Can anyone spare a few minutes and share some light, please ?

Thanks
Emil