[buildd-tools-devel] Bug#695287: Bug#695287: sbuild: synthetic cross-build-dependencies for compilers

[Roger Leigh]

On Thu, Dec 06, 2012 at 04:54:23PM +0000, Colin Watson wrote:
> When I was writing my patch for #695203, it occurred to me that this
> offered an opportunity for sbuild to step in and synthesise
> build-dependencies in some situations.  A possible design would be as
> follows:
> 
>   When cross-building, if the package being built build-depends on A
>   (taking any [] into account), A is not Multi-Arch: foreign, and A-HOST
>   exists in the apt cache, then rewrite the build-dependency to
>   "A:native, A-HOST" (including any versioning present).
> 
> Wookey suggested that we might also want something for people who don't
> use sbuild; I think perhaps a similar algorithm in 'dpkg-checkbuilddeps
> -aHOST' would be useful and reasonable.  (CCing debian-dpkg.)  An
> alternative to the "exists in the apt cache" rule, which I can imagine
> being troublesome, might be to have a hardcoded list of relevant
> packages; this would change from time to time but hopefully not too
> often.  Or we could have a package control field for "there's a cross
> version of this".

I think this all sounds reasonable.  I'll be happy to look over any
cross-building stuff for sbuild; I'm afraid my multiarch knowledge
is still lacking some of the intricacies though.  It's certainly
not a problem to add additional dependencies to the dependency
package when cross-building.

We might also want to look a bit further at automatically setting up
the appropriate foreign arches in dpkg/apt so that this is all
automatically installable as well (unless this was already taken
care of--I can't recall offhand), if we end up with multiarch
deps which would otherwise not be available.


Regards,
Roger

-- 
  .''`.  Roger Leigh
 : :' :  Debian GNU/Linux    http://people.debian.org/~rleigh/
 `. `'   schroot and sbuild  http://alioth.debian.org/projects/buildd-tools
   `-    GPG Public Key      F33D 281D 470A B443 6756 147C 07B3 C8BC 4083 E800