[gentoo-dev] [RFC] EAPI={3,4} offset-prefix semantics mandatory?

[gentoo-dev] [RFC] EAPI={3,4} offset-prefix semantics mandatory?

[Fabian Groffen]

With the current route where EAPI=3 will simply be EAPI=2 +
offset-prefix support, and EAPI=4 will be EAPI=3 + some other stuff, the
following question arose:

  Should an ebuild using an EAPI that has offset-prefix support make the
  use of that support mandatory or optional?

In other words, one can perfectly fine write an ebuild EAPI=3 that will
not work in an offset-prefix install, due to improper absence of EPREFIX,
ED and EROOT.  Should we allow this formally, or not?

Why is this a problem?  Simply because it can be done, but more because
EAPI=4 will introduce features a developer would like to use/rely on,
while she/he does not want, or is not able to write the ebuild in a
Prefix conforming way.

The pros for forcing ebuilds to be offset-prefix aware are:
- an ebuild having EAPI >= 3 (as it looks now) is supposed to work
  for Prefix users
- hence also obviously is (supposed to be) checked for Prefix
- repoman might be able to check for obvious mistakes regarding
  offset-prefix installations

The cons:
- all developers need to be aware of how Prefix works, and be able to
  write ebuilds for it (I can post all the answers to the Prefix quiz)
- basically requires a Prefix to be setup to test
- it will stop developers to some degree to use higher EAPIs in the
  worst case

The pros for allowing ebuilds that have an offset-prefix aware EAPI to
ignore the offset-prefix are:
- easy drop-in replacement for devs, basically the contra of all the
  cons of the previous approach.

The cons:
- not immediately clear which ebuild is offset-prefix aware (could look
  at Prefix keywords)
- needs proper rules; an ebuild that has offset-prefix support may not
  have this support removed again (breaks Prefix users, how to enforce?)
- ebuilds may get offset-prefix support at a later stage, which may not
  entirely be understood/noticed by (their maintaining) devs

Please voice your opinion and share your insights, if any.


-- 
Fabian Groffen
Gentoo on a different level

Re: [gentoo-dev] [RFC] EAPI={3,4} offset-prefix semantics mandatory?

[Ulrich Mueller]

>>>>> On Tue, 15 Dec 2009, Fabian Groffen wrote:

> With the current route where EAPI=3 will simply be EAPI=2 +
> offset-prefix support,

That's not entirely right, as EAPI 3 will also include mtime
preservation.

>   Should an ebuild using an EAPI that has offset-prefix support make the
>   use of that support mandatory or optional?

Optional.

> In other words, one can perfectly fine write an ebuild EAPI=3 that
> will not work in an offset-prefix install, due to improper absence
> of EPREFIX, ED and EROOT. Should we allow this formally, or not?

I'd say you can only claim Prefix support for an ebuild, when that
ebuild has been tested under Prefix, i.e. when KEYWORDS contain at
least one Prefix architecture.

> The pros for forcing ebuilds to be offset-prefix aware are:
> - an ebuild having EAPI >= 3 (as it looks now) is supposed to work
>   for Prefix users

Again, we have KEYWORDS for this.

> - hence also obviously is (supposed to be) checked for Prefix

I don't see this as a pro. At least I don't want to delay any updates
to EAPI 3 (which I need for mtime preservation), only to ensure that
the ebuild is also working in Prefix. Most of my ebuilds in question
aren't even in the Prefix overlay.

Also there are some packages that are Linux-only and will never run on
Prefix. Certainly we don't want to restrict them to EAPI <= 2 forever?

Ulrich

Re: [gentoo-dev] [RFC] EAPI={3,4} offset-prefix semantics mandatory?

[Peter Volkov]

В Втр, 15/12/2009 в 19:59 +0100, Fabian Groffen пишет:
>   Should an ebuild using an EAPI that has offset-prefix support make the
>   use of that support mandatory or optional?

I think no. Without real testing that package works in prefix there is
no need to bother and create illusion that it does.

> (I can post all the answers to the Prefix quiz)

I think this is good idea in any case. Could you post this (on -core, of
course)?


-- 
Peter.

Re: [gentoo-dev] [RFC] EAPI={3,4} offset-prefix semantics mandatory?

[Fabian Groffen]

On 16-12-2009 09:29:07 +0300, Peter Volkov wrote:
> В Втр, 15/12/2009 в 19:59 +0100, Fabian Groffen пишет:
> >   Should an ebuild using an EAPI that has offset-prefix support make the
> >   use of that support mandatory or optional?
> 
> I think no. Without real testing that package works in prefix there is
> no need to bother and create illusion that it does.

Does your no mean mandatory or optional?

> > (I can post all the answers to the Prefix quiz)
> 
> I think this is good idea in any case. Could you post this (on -core, of
> course)?

I'll remove all the bits from the quiz that are (no longer) relevant,
and then post them, and their answers.  I don't see much secret in the
answers, or do recruiters want to use some of the questions for future
quizzes?


-- 
Fabian Groffen
Gentoo on a different level

[gentoo-dev] Re: [RFC] EAPI={3,4} offset-prefix semantics mandatory?

[Christian Faulhammer]

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Hi,

Fabian Groffen <grobian@gentoo.org>:

> On 16-12-2009 09:29:07 +0300, Peter Volkov wrote:
> > В Втр, 15/12/2009 в 19:59 +0100, Fabian Groffen пишет:
> > >   Should an ebuild using an EAPI that has offset-prefix support
> > > make the use of that support mandatory or optional?
> > 
> > I think no. Without real testing that package works in prefix there
> > is no need to bother and create illusion that it does.
> 
> Does your no mean mandatory or optional?

 As I read it: Optional.  And that is also my vote here, in the end we
have KEYWORDS.

> I'll remove all the bits from the quiz that are (no longer) relevant,
> and then post them, and their answers.  I don't see much secret in the
> answers, or do recruiters want to use some of the questions for future
> quizzes?

 Post it on -core and we can decide then.

V-Li

-- 
Christian Faulhammer, Gentoo Lisp project
<URL:http://www.gentoo.org/proj/en/lisp/>, #gentoo-lisp on FreeNode

<URL:http://gentoo.faulhammer.org/>

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Re: [gentoo-dev] [RFC] EAPI={3,4} offset-prefix semantics mandatory?

[Jeremy Olexa]

On Tue, 15 Dec 2009 19:59:44 +0100, Fabian Groffen <grobian@gentoo.org>
wrote:
> With the current route where EAPI=3 will simply be EAPI=2 +
> offset-prefix support, and EAPI=4 will be EAPI=3 + some other stuff, the
> following question arose:
> 
>   Should an ebuild using an EAPI that has offset-prefix support make the
>   use of that support mandatory or optional?

As a Gentoo Linux developer, I certainly wouldn't want to say that my
EAPI-3+ ebuilds are guaranteed to work on Gentoo Prefix platforms without
testing(keywording) it.

As a Gentoo Prefix user, I certainly wouldn't want devs that don't know
how to test an ebuild to work on Gentoo Prefix to say that it works.
As a Gentoo Prefix developer, I certainly don't want to fix bugs by people
that don't know how test on (or have access to) Gentoo Prefix.

In the end, every Gentoo Prefix arch needs a specific keyword anyway.
Unless that changes, I can't say that I see many benefits to making
offset-prefix support mandatory in EAPI-3. OTOH, if it is mandatory and I
screw it up for Gentoo Prefix platforms, no one will know until it gets
keyworded (and hence tested).

-Jeremy


> In other words, one can perfectly fine write an ebuild EAPI=3 that will
> not work in an offset-prefix install, due to improper absence of
EPREFIX,
> ED and EROOT.  Should we allow this formally, or not?
> 
> Why is this a problem?  Simply because it can be done, but more because
> EAPI=4 will introduce features a developer would like to use/rely on,
> while she/he does not want, or is not able to write the ebuild in a
> Prefix conforming way.
> 
> The pros for forcing ebuilds to be offset-prefix aware are:
> - an ebuild having EAPI >= 3 (as it looks now) is supposed to work
>   for Prefix users
> - hence also obviously is (supposed to be) checked for Prefix
> - repoman might be able to check for obvious mistakes regarding
>   offset-prefix installations
> 
> The cons:
> - all developers need to be aware of how Prefix works, and be able to
>   write ebuilds for it (I can post all the answers to the Prefix quiz)
> - basically requires a Prefix to be setup to test
> - it will stop developers to some degree to use higher EAPIs in the
>   worst case
> 
> The pros for allowing ebuilds that have an offset-prefix aware EAPI to
> ignore the offset-prefix are:
> - easy drop-in replacement for devs, basically the contra of all the
>   cons of the previous approach.
> 
> The cons:
> - not immediately clear which ebuild is offset-prefix aware (could look
>   at Prefix keywords)
> - needs proper rules; an ebuild that has offset-prefix support may not
>   have this support removed again (breaks Prefix users, how to enforce?)
> - ebuilds may get offset-prefix support at a later stage, which may not
>   entirely be understood/noticed by (their maintaining) devs
> 
> Please voice your opinion and share your insights, if any.