[arch-general] announce libraries in provides=()

[mike lojkovic]

Suggesting pacman add some portage style features for dependency resolution
and packaging? Modifying packages on a local system to fix bugs caused by
versions of packages?

On Thu, May 16, 2019, 3:10 AM Erich Eckner via arch-general <
arch-general at archlinux.org> wrote:

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> Hi,
>
> I would like to encourage adding provided libraries of a package to its
> "provides=()" array in the PKGBUILD.
>
> Some background:
>
> Updating the system libraries may break manually compiled packages. Having
> the version of the system libraries fixed in the dependencies of the
> manually compiled package, this could be avoided, because then pacman
> would refuse to replace the system library.
> The current behaviour can be annoying if the manually compiled package is
> vital (e.g. a mail server), requires some time for compilation and/or
> fails to build for unrelated reasons.
>
>
> If the libraries are added to the provides array, makepkg will
> automatically version those dependencies.
>
> libvorbis, for example has
> provides=('libvorbis.so' 'libvorbisenc.so' 'libvorbisfile.so')
> in the PKGBUILD which becomes
> Provides: libvorbis.so=0-64  libvorbisenc.so=2-64  libvorbisfile.so=3-64
> in the package.
>
> This way, external packages can pick up versioned dependencies on the
> library by using "depends=()".
>
> Since my proposal[1] got denied for a single package, I currently have a
> horrible hack in place which manually adds depends= entries in the
> package() function looking at the compiled binaries with objdump. Because
> I can only add dependencies based on the $pkgver of the package, but not
> on the soname version of the library, I have to recompile for each version
> change - not only the ones which actually change soname. The only current
> alternative would be to manually build the required libraries, too (with
> the provides=() entries added) - which is obviously also a bad idea.
>
> Can we please have a todo list of packages that provide libraries in
> /usr/lib but not announce them in the metadata?
>
> Or should we enable makepkg to automatically search through the library
> directory? (Probably not a good idea, as there might be differing
> locations, libraries which should deliberately not be announced, etc. ...)
>
> Or is my approach flawed from the beginning? How should I else circumvent
> breaking the linking?
>
> regards
> Erich Eckner
>
> 1] https://bugs.archlinux.org/task/61018
>
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