Re: [gentoo-portage-dev] [RFC] Store [,R,P]DEPEND with unevaluated use conditionals in vdb

[Gentoo]

On Sat, 2010-04-24 at 20:00 +0200, Sebastian Luther wrote:
> Am 24.04.2010 13:32, schrieb Gentoo:
> > On Fri, 2010-04-23 at 22:31 -0700, Zac Medico wrote:
> >> On 04/23/2010 05:43 AM, Sebastian Luther wrote:
> >>> Someone might come up with some logic to detect new use flags in
> >>> *DEPEND, but this looks like a hack to me.
> >>
> >> It doesn't seem too bad to me.
>
> It doesn't work, because it's not guaranteed, that only use flag from
> IUSE are used in use conditionals. That means you can't do it reliably
> without the unevaluated value.
>
> >>
> >>> The clean solution is to
> >>> store the unevaluated string.
> >>
> >> Do you want to do this for $PKGDIR/Packages as well? We've always
> >> evaluated USE conditionals in there since we were copying the
> >> behavior of the older genpkgindex tool and that's how it behaved.
> >>
>
> We should do it there too for the same reason as for storing it in the
> vdb. Never heard of that tool, but anyone handling portage's binpkgs
> should use the portage api which provides an easy way to evaluate the
> use conditionals.
>
> >> Also note that if we want to rely on having unevaluated strings then
> >> we'll probably want to try to get alternative package managers to
> >> behave the same way (maybe specify it in PMS).
>
> The vdb isn't covered by PMS. Paludis stores the unevaluated value,
> pkgcore stores the evaluated value.
>
> >>
> >>> Question is: Does anyone have a good argument to not use the old
> >>> behavior again?
> >
> > space and ease of parsing for minimal pkg mergers.
> >
> >
>
> Minimal mergers have to handle it anyway, since this has been the old
> behavior until some weeks ago.

We actually had flattened R/DEP's before for a while. Then they got
removed then noew added back.

> For portage API users, the difference is
> a (rather long) one liner.


> What do you mean with space?

The vdb is getting rather bloated. Anything that cuts down excess waste
there for the masses I tend to be in favor of.

> >>>
> >>> Sebastian
> >>>
> >>> [1] commit e6be6590e99522f9be69e2af8eff87919d9bf31f on 2010-02-14
> >>
> >> I think we'll have to handle the evaluated strings anyway since this
> >> code has already been released and stabilized in portage-2.1.8.x,
> >> and USE conditionals have been evaluate in $PKGDIR/Packages for even
> >> longer. Because of this, I see little or no benefit in changing it
> >> back to unevaluated strings at this point.
> >
> > Good. Thanks for not reverting back to those old behaviors.
>
> And the new use case isn't of any relevance?
>
> As a compromise: What about storing both values?

That just add bloat back. I think the real problem here in the example
you listed in the first email, is that ebuild authors should be bumping
a package when adding/removing functionaliy provided by IUSE. Infact
it's even a policy & part of our own ebuild quizzes that they should
bump the pkg (eclasses excluded).

-- 
Gentoo <solar@g.o>
Gentoo Linux