can an overlay force a USE flag on a host?
 

In cont. to my prev. question
(http://archives.gentoo.org/gentoo-portage-dev/msg_9973fd6c12d7c2088457697f49ea2f5e.xml)


Can I append use.force/package.use.force/package.use or similar to an
overlay, and by that control USE flags on the host?


Though not necessarily related, I'm trying to resolve a broader issue:
whether it is possible to extend a profile via an overlay.


I've read http://bugs.gentoo.org/show_bug.cgi?id=133740#c6. Also, I've
found http://en.gentoo-wiki.com/wiki/Custom_Profiles which states how
custom profiles can be integrated into a system, yet with the caveat of
modifying local portage files (removing the symlink to the profile). I'd
appreciate to know if it's also possible to gain similar results w/o
touching files on the hosting portage setup.


In a/m bug, the lack of documentation in this area is mentioned . I'm
wondering if this has changed since those comments were written, as I'm
confounded by bits and pieces I'm fishing out w/google.


Amit

can an overlay force a USE flag on a host?
 

On 12/31/2009 06:41 AM, Amit Dor-Shifer wrote:
> In cont. to my prev. question
> (http://archives.gentoo.org/gentoo-portage-dev/msg_9973fd6c12d7c2088457697f49ea2f5e.xml)
>
>
> Can I append use.force/package.use.force/package.use or similar to an
> overlay, and by that control USE flags on the host?

With EAPI 1 and greater you can use IUSE="+flag" to enable flags by
default in an ebuild. If you need to modify the profile then this is
a good way to do it:

http://en.gentoo-wiki.com/wiki/Custom_Profiles#Simple_Profile_Setup

> Though not necessarily related, I'm trying to resolve a broader issue:
> whether it is possible to extend a profile via an overlay.
>
> I've read http://bugs.gentoo.org/show_bug.cgi?id=133740#c6. Also, I've
> found http://en.gentoo-wiki.com/wiki/Custom_Profiles which states how
> custom profiles can be integrated into a system, yet with the caveat of
> modifying local portage files (removing the symlink to the profile). I'd
> appreciate to know if it's also possible to gain similar results w/o
> touching files on the hosting portage setup.

Other than IUSE defaults, the only way is to create a
/etc/make.profile directory and list multiple profiles in the
"parent" file.

> In a/m bug, the lack of documentation in this area is mentioned . I'm
> wondering if this has changed since those comments were written, as I'm
> confounded by bits and pieces I'm fishing out w/google.

The information in the wiki seems current.
--
Thanks,
Zac

can an overlay force a USE flag on a host?
 

On 12/31/2009 11:57 AM, Zac Medico wrote:
> Other than IUSE defaults, the only way is to create a
> /etc/make.profile directory and list multiple profiles in the
> "parent" file.

I forgot the mention that as a workaround for bug 238887 you might
check for the required USE combination in pkg_setup and die if you
requirements aren't met. For example, this is how the openldap
ebuild ensures that sasl is enabled when cxx is enabled. It's not
very friendly but it works.
--
Thanks,
Zac

can an overlay force a USE flag on a host?
 

Zac Medico wrote:

On 12/31/2009 06:41 AM, Amit Dor-Shifer wrote:


In cont. to my prev. question
(http://archives.gentoo.org/gentoo-portage-dev/msg_9973fd6c12d7c2088457697f49ea2f5e.xml)


Can I append use.force/package.use.force/package.use or similar to an
overlay, and by that control USE flags on the host?



With EAPI 1 and greater you can use IUSE="+flag" to enable flags by
default in an ebuild.
Yes, but AFAIK, enabling a USE flag by-default only affects the enabling
ebuild, not its dependencies. Specifically, By setting "+myflag" in an
ebuild, I cannot incur a rebuild of a dependent which is also using this
flag.


Appending "myflag" to the USE set via a profile would achieve that behavior.




In a/m bug, the lack of documentation in this area is mentioned . I'm
wondering if this has changed since those comments were written, as I'm
confounded by bits and pieces I'm fishing out w/google.



The information in the wiki seems current.


Would that be http://en.gentoo-wiki.com/wiki/Overlay ?
If so, then

* your a/m comment #6 in the bug, clarifying that the 'profiles'
directory has nothing to do with portage profiles is most valuable.

<QUOTE>

Don't let the directory name "profiles" make you think that it has anything to do with a profile



<UNQUOTE>
Well, it actually did make me think that. it looked plausible that
an overlay could extend a portage profile.

* The article also mentions "portage overlay specifications", but
does not cite it.
* That an overlay can extend package.[un]mask is also not mentioned
there.

I'm currently reluctant to contribute documentation myself, since I'm
lacking key concepts. I'd be happy to do so if I had a more thorough
understanding.


Amit

can an overlay force a USE flag on a host?
 

On 01/03/2010 12:48 AM, Amit Dor-Shifer wrote:
> Yes, but AFAIK, enabling a USE flag by-default only affects the enabling
> ebuild, not its dependencies. Specifically, By setting "+myflag" in an
> ebuild, I cannot incur a rebuild of a dependent which is also using this
> flag.

Right, but if the ebuild has a USE dependency (supported with EAPI
2) then at least emerge will notify the user that they need to
enable the flag.

> Appending "myflag" to the USE set via a profile would achieve that
> behavior.
>
>>
>>> In a/m bug, the lack of documentation in this area is mentioned . I'm
>>> wondering if this has changed since those comments were written, as I'm
>>> confounded by bits and pieces I'm fishing out w/google.
>>>
>>
>> The information in the wiki seems current.
>>
> Would that be http://en.gentoo-wiki.com/wiki/Overlay ?
> If so, then
>
> * your a/m comment #6 in the bug, clarifying that the 'profiles'
> directory has nothing to do with portage profiles is most valuable.
>
> <QUOTE>
>
> Don't let the directory name "profiles" make you think that it has
> anything to do with a profile
>
> <UNQUOTE>
> Well, it actually did make me think that. it looked plausible that
> an overlay could extend a portage profile.

It's a common assumption, but doing that is not necessarily a
desirable because it can be invasive. Often, a user simply wants to
use some ebuilds from an overlay without having it triggering an
invasive bunch of global configuration changes.

> * The article also mentions "portage overlay specifications", but
> does not cite it.

repo_name is documented in `man 5 portage`.

> * That an overlay can extend package.[un]mask is also not mentioned
> there.

Yes, the 'global' package.[un]mask files in the root profiles/
directory do extend those from the main portage tree, but this
behavior is not necessarily desirable because it can be invasive.
There was some complaint in the past about the gnome overlay relying
on this behavior since alternative package managers (paludis and
pkgcore) didn't support it and they did not intend to add support
for it.

> I'm currently reluctant to contribute documentation myself, since I'm
> lacking key concepts. I'd be happy to do so if I had a more thorough
> understanding.

Let us know if you have any more questions.
--
Thanks,
Zac