[PATCH wayland] wayland-egl: Ignore underscored symbols in ABI check

[Emil Velikov]

On 20 March 2018 at 12:11, Daniel Stone <daniel at fooishbar.org> wrote:
> On 20 March 2018 at 11:55, Emil Velikov <emil.l.velikov at gmail.com> wrote:
>> On 20 March 2018 at 11:46, Daniel Stone <daniel at fooishbar.org> wrote:
>>> Sure. As on IRC though, we definitely need to add at least _ftext for
>>> MIPS anyway:
>>> https://gitlab.gnome.org/GNOME/glib/commit/ad12142943e0f20ed9583c9d6bf50f6262110c74
>>>
>>> And probably some more for ARM toolchains using other linkers:
>>> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0474k/pge1362066045758.html
>>>
>>> Doing a quick check across all the architectures on Debian shows that
>>> your updated list is also missing _fbss, _fdata, and _ftext. So we'd
>>> need to respin for those as well, but I think at this point the
>>> inconvenience of maintaining a list of every linker's implementation
>>> detail on every platform, outweighs the risk of an exported
>>> underscore-prefixed symbol slipping through review.
>>
>> I think you're preemptively worried about this. Plus there's no need
>> to add every symbol a search could find.
>>
>> Even then, ask yourself the question:
>> Which is better - updating an ugly looking list once in a blue moon or
>> having apps use internal API?
>>
>> As said above: _if_ it turns out to be labour intensive - fine remove it.
>> We've already spend more time researching than what the [expected]
>> maintenance for 1 year would be ;-)
>
> It all depends on how you view scope and probability.
>
> I don't agree my concern is preemptive: we've just shipped a beta
> where 'make check' fails on a few architectures, and the proposed fix
> (adding several symbols to the platform list) will still fail on
> architectures Debian ships on, until it also adds _fbss, _fdata and
> _ftext. I think my suggestion is reasonable: it fixes the very real
> problem, in a way which avoids expanding the scope of our ABI checker
> to include the implementation details of every linker/architecture
> pair that people use Wayland on. The cost of this is the probability
> that someone manages to add a new underscored symbol marked with
> WL_EXPORT into a library which is currently 105 LoC, and have no-one
> notice that in review. I think that's a reasonable tradeoff.
>
Right, hopefully there won't be any internals leaked/used by other projects.
I reserve myself the right of the lovely "I told you so".

Feel free to continue with whichever solution you feel comfortable with.

-Emil