Bug 422513

Summary:	PMS is unclear on EXPORT_FUNCTIONS effective order
Product:	Gentoo Hosted Projects	Reporter:	Michał Górny <mgorny>
Component:	PMS/EAPI	Assignee:	Package Manager Specification <pms>
Status:	RESOLVED FIXED
Severity:	normal	CC:	ionic, sam
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
See Also:	https://bugs.gentoo.org/show_bug.cgi?id=399039
Whiteboard:
Package list:		Runtime testing required:	---

Description Michał Górny archtester

2012-06-20 08:21:52 UTC

PMS seems a bit laconic regarding EXPORT_FUNCTIONS. While one _may_ get an idea what it is supposed to be used for, there's no explanation what happens when EXPORT_FUNCTIONS is used within multiple inherited eclasses.

Especially it lacks information that:

a) indirectly inherited eclasses have precedence over explicitly inherited ones:

a.eclass, b.eclass export pkg_setup()
c.eclass inherits a
if ebuild does 'inherit a b c', a_pkg_setup() will be called


b) calls to EXPORT_FUNCTIONS determine the order, not inherits:

in case listed above, vapier introduces double-inherit prevention in a.eclass
now if ebuild does 'inherit a b c', b_pkg_setup() will be called


c) whether eclass API/exports is allowed to change between successive inherits:

- due to 'configuration' variables changing,
- due to 'double include prevention'.

(where basically one defeats the other)


The above behavior I was able to reproduce using portage, pkgcore & paludis. Not sure if that's what we want in the spec though.

Comment 1 Brian Harring (RETIRED) gentoo-dev

2012-11-26 09:03:11 UTC

Bump; any life on PMS bugs or have the cows fled the barn?

Comment 2 Ulrich Müller gentoo-dev

2012-11-26 09:11:23 UTC

It would certainly help if a patch was attached.

Comment 3 Larry the Git Cow gentoo-dev

2021-09-01 17:34:58 UTC

The bug has been referenced in the following commit(s):

https://gitweb.gentoo.org/proj/pms.git/commit/?id=f5f8e42eeb8ea1e8c2ac182f30214ef0c559dd88

commit f5f8e42eeb8ea1e8c2ac182f30214ef0c559dd88
Author:     Ulrich Müller <ulm@gentoo.org>
AuthorDate: 2021-08-29 08:10:29 +0000
Commit:     Ulrich Müller <ulm@gentoo.org>
CommitDate: 2021-08-31 16:02:50 +0000

    eclasses.tex: Clarify precedence of EXPORT_FUNCTIONS calls
    
    Clarify that the last call to EXPORT_FUNCTIONS takes precedence over
    earlier calls.
    
    Unfortunately, we need an exception when inherit is called after
    EXPORT_FUNCTIONS because Portage changed its behaviour in 2009:
    https://gitweb.gentoo.org/proj/portage.git/commit/?id=06d4433e8b8be60d606733b9e23f57f8a5869d8f
    
    Pkgcore and Paludis apply precedence consistently based on call order
    of EXPORT_FUNCTIONS.
    
    Bug: https://bugs.gentoo.org/399039
    Bug: https://bugs.gentoo.org/422513
    Signed-off-by: Ulrich Müller <ulm@gentoo.org>

 eclasses.tex | 4 ++++
 1 file changed, 4 insertions(+)