Re: [oe-core] [RFC] meson.bbclass: pkg-config vs pkgconf

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Mon, 2024-06-03 at 13:02 -0500, Randolph Sapp wrote:
> Forgive my ignorance, but is there any particular reason why pkg-
> config is preferred over pkgconf for meson related recipes?

Yes, as to try and mix both pkg-config and pkgconf would be a path to
madness.

> It seems the two treat the usage of the PKG_CONFIG_SYSROOT_DIR
> variable differently, resulting in issues when build scripts
> attempting to use package config variables directly.

Right, this is basically the problem. We have a long history of using
pkg-config, we worked with upstream to merge sysroot support and it is
the standard we built around.

pkgconf then came along and decided it would be a great idea to have
some slightly different behaviour. We did originally plan to have a
switchable virtual/ provider but due to the differences in behaviour it
doesn't work.

Things are bad enough that there are two standards. Saying "if building
with meson, it behaves differently again" would be a nightmare.

I have been asked to switch everything to pkgconf however I suspect
that would also involve carrying patches and would end up as ton of
work to be incompatible with a different set of software. I'm therefore
not keen on that either.

> If there's not an explicit reason we're preferring pkg-config, would 
> anyone be opposed to switching it out for pkgconf for meson related 
> packages? Of course, with a note about this behavior discrepancy. It 
> would reduce these Yocto specific patches and align meson behavior
> with distros that currently default to pkgconf.

Personally, I think it would just confuse things even more. xcb-proto
might get used by meson or non-meson software. Mesa might get used by
either too. Keeping it simple and saying "pkg-config behaviour"
everywhere is simpler IMO.

Cheers,

Richard