Re: [gentoo-dev] Gentoo Prefix: on EPREFIX, ED and EROOT inside ebuilds

[Jeremy Olexa]

Some questions answered. snipped the rest.

Denis Dupeyron wrote:
> 2009/10/18 Tomáš Chvátal <scarabeus@g.o>:
>> Why on earth portage simply does not detect the prefix enviroment is being run
>> and then INTERNALY switch D->ED and other variables.
>
> If that means we can get away without touching ebuilds, apart from
> changing their EAPI variable, then that's absolutely what we have to
> do. I'd like things to be done the right way though (see below).

When you change econf to do --prefix=${EPREFIX}/usr then you cannot 
simply s/D/ED/ for everything. I hope this makes sense when you think 
about it. ;)

   src_install() {
     emake DESTDIR="${D}" install || die
     mv "${ED}"/usr/bin/{,exuberant-}ctags || die
   }

But then again, some ebuilds need no changing once you fix econf to do 
the work, which is nice.

>
> On Fri, Nov 13, 2009 at 4:43 AM, Ulrich Mueller <ulm@g.o> wrote:
>> However, there is need for additional discussion. From the council
>> meeting log I could extract the following open questions:
>
> It would be preferable for the discussion to happen on this list
> before the meeting or we'll end up postponing again due to having more
> questions coming up at that time.

We are willing to talk, but it always seems like the Council is "not 
prepared" no matter what we do. Hope everyone involved can change that.

>
>>  2. Should the Prefix team be allowed to do the necessary changes to
>>     ebuilds themselves, or should it be done by the respective
>>     maintainers?
>
> I think here it's obvious that anybody who is an ebuild dev and sees
> anything to fix (prefix or else) is encouraged to go ahead and do it,
> as we've always done. The recommendation is and will always be to talk
> to the current maintainers out of politeness and to be extra careful
> (i.e. usually letting the maintainers do it) in case of
> system/tricky/exotic package. We don't give full cvs access to the
> whole tree to all ebuild devs for nothing.

It is quite obvious that we are not trying to make trouble. Talk is 
cheap, so we prefer that. But, we see no need to ask permission to add 
~prefix keywords, same as other arch teams.

Currently, 'repoman -d full' will fail in some packages. We are fixing this.

> Also I think it would be nice if somebody took care of a portage
> patch, since I hear it is rather simple. Fabian again? Or Zac? Any
> other volunteers?
>
> I would prefer to have all the pieces in places before the next
> meeting so that we can vote on the real thing and have prefix
> implemented the right way before the end of the year.

portage devs and prefix devs have agreed that it is rather 'easy' to 
merge the prefix-portage branch. Just waiting.. ;) We have access to 
check into the portage repo, so this should not hold anything up 
regarding any decisions.

>
>>  6. (Any question that I've missed?)

>> How are scripts using #!shebangs going to work?
>> You write an ebuild, and you DEPEND upon >=foo-3, because the build
>> process includes some foo code. The foo code is executed via
>> scripts using #!/usr/bin/foo. Normally, this is fine.
>> But on prefix, /usr/bin/foo might be a crappy, OS X mangled foo-2
>> that's no good. So even though you've got the foo-3 dep met, it'll be
>> met in /opt/Gentoo/blah, so your package will fail.

The prefix-portage branch has a nice feature that fixes shebangs 
automatically to be ${EPREFIX}/foo instead of /foo. It has even caught 
some Gentoo Linux bugs.

>
>> How are ebuilds to be marked as supporting prefix or not?
> (Here I'm guessing that changing the EAPI variable will do)

Gentoo Prefix has keywords. So if EAPI 3 has ED/EROOT support but the 
ebuild doesn't use them then the ebuild does not need an EAPI bump. In 
this case, please rephrase your question to be "How are ebuilds to be 
marked as working on a prefix arch or not?" and then it is clear that it 
is the same as Gentoo Linux.

>
>> Why is there only a single permitted installation path?
> (I'm under the impression this is a limitation of the windows
> installer but not of prefix itself. So patching the installer would
> fix that)

My installation path on my 6-8 prefix arches is in my NFS home. If you 
are referring to the Windows special installation package, well..that is 
just a "stage4" installer with binary packages. The windows installer is 
no where near the heart of Gentoo Prefix, instead it is a product of 
Gentoo Prefix and a convenience factor offered by another Prefix dev. It 
showcases the possibilities quite well, IMO.

You can set EPREFIX to anything. One of our users even set it to "/" - 
which we don't endorse but it is possible. :)

>
>> What exactly is expected from a prefix-compliant package manager to
>> support full prefix installs, as opposed to just supporting installs
>> to / with prefix-aware ebuilds?
> (The PMS patch should answer that)
>
> Denis.
>