Re: [gentoo-dev] EAPI 7, BDEPEND and pkg_*inst

[Michał Górny]

W dniu śro, 30.05.2018 o godzinie 13∶49 +0200, użytkownik Michael
Haubenwallner napisał:
> Hi,
>
> HOORAY, seems like EAPI 7 might be able to obsolete the "prefix-chaining"
> portage patch I've carried in prefix-overlay all the time, thank you for that!

I'm sorry for not replying earlier.  I meant to, but I failed to mark
the mail and I've forgot about it.

>
> However, a first thing being unclear already came up when bumping EAPI 6 to 7:
>
> For example, the current app-misc/ca-certificates ebuild (EAPI 6) contains:
>
>  # c_rehash: we run `c_rehash`
>  # debianutils: we run `run-parts`
>  RDEPEND="${DEPEND}
>      app-misc/c_rehash
>      sys-apps/debianutils"
>
>  pkg_postinst() {
>     if [ -d "${EROOT}/usr/local/share/ca-certificates" ] ; then
>         # if the user has local certs, we need to rebuild again
>         # to include their stuff in the db.
>         # However it's too overzealous when the user has custom certs in place.
>         # --fresh is to clean up dangling symlinks
>         "${EROOT}"/usr/sbin/update-ca-certificates --root "${ROOT}"
>     fi
>  }
>
> Thing is, these RDEPENDs are not really required to "run" ca-certificates, but to
> administrate it - which eventually is done on the CBUILD machine (from within the
> ebuild, like in pkg_postinst currently), not necessarily on the CHOST machine.
>
> So I do not necessarily want these RDEPENDs to be installed on the CHOST machine,
> given that they may not be executed from within the CBUILD machine at all.
>
> So the first idea is to move both RDEPENDs into BDEPEND.  But then, they are
> not guaranteed to be available during pkg_postinst - like for a binary package.
>
> Question now is: Is this wrong behaviour in the ebuild,
> or is this something where EAPI 7 is still insufficient for?

It's a known deficiency discovered just a while too late to address it. 
It comes from the fact that we never really had proper dependencies for
pkg_*inst phases.  So far we've ignored the problem because our work-
arounds were sufficient for our use cases but cross definitely needs
something better.

> When this is wrong (probably independent of EAPI 7 already) in the ebuild:
> How can the ebuild get such a use case right, especially with EAPI 7?

I think the 'closest' thing to right would be to use BDEPEND+RDEPEND. 
It won't cover cross+binpkg but I guess it's as good as you can get.

-- 
Best regards,
Michał Górny