[buildd-tools-devel] sbuild: multiarch build support

[Wookey]

+++ Geoffrey Thomas [2014-08-31 22:45 -0700]:
> On Fri, 29 Aug 2014, Wookey wrote:
> 
> >The patch simply identifies explicit arch-qualified build-deps (of the
> >form libfoo:arch) and if present runs dpkg --add-foreign-architecture
> >arch (as it already does for cross-builds). Apt takes care of the rest.
> >
> >The second part (for removing the arch after the build (on permanent
> >chroots)) needs more work as usually there are binaries of the foreign
> >arch installed so the arch-removal fails.
> >
> >Comments on the code are welcome.
> 
> Maybe these should be obvious, but I'm curious about these two
> things I don't understand:
> 
...
> 
> 2. While we probably don't want to go this route, how does this
> differ from simply adding all architectures in the archive as
> foreign architectures, unconditionally? Is there a risk of builds
> pulling in cross-arch dependencies when not needed?

Yes, there is a risk, at least on unstable. And I know that some
people are very unenthusiastic about enabling lots of arches
unconditionally in buildd chroots, not least because it greatly
increases the mmeory requirements (and presumably solution times) for
apt. The most likely way things would go wrong is that a build-dep
might be built for one arch but not another (yet, due to buildd
speeds), and marked MA:foreign, so only the wrong-arch version is
available. This would satisfy the build-dep but not actually run.

It may be that enabling some foreign arches on some buildds makes
sense once we've had more testing, but as its easy to only enable them
on an 'as required' basis, this is clearly much safer and is
acceptable to buildd admin people, whilst generally enabling lots of
(all?) foreign arches is not. Hence the patch.

Wookey (Back from 2 weeks hols)
-- 
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