[Reproducible-builds] On which arch should Arch:all packages be built? addition to scsh-0.6, we should not be trying to build these packages on amd64:

[Santiago Vila]

On Fri, Nov 27, 2015 at 11:12:50AM +0100, Jérémy Bobbio wrote:
> I think the question can be phrased as: should architecture-independent
> packages be buildable on all architectures?
> 
> My own answer would be: yes, as long as they don't mandate a particular
> architecture in their Build-Depends-Indep.
> 
> Is there something wrong with this answer?

My answer would be: Not necessarily.

In theory, the build process could need to compile a program which is
used to create some file which is later used in the binary-indep target.

Such program does not need to be portable because, well, some programs
are just not portable. Not in the sense that it's inherently non-portable
but just in the sense that nobody had the time to "port" it yet.

If we had a case like this, an architecture field in the source
package saying "i386 all" would mean that we could do all this:

"dpkg-buildpackage" under i386 to build the i386.deb and the all.deb.
"dpkg-buildpackage -A" under i386 to build only the all.deb.
"dpkg-buildpackage -B" under i386 to build only the i386.deb.

and at the same time it would be possible that the source package is
just not designed or ready to build the all.deb under, say, amd64.

In most cases it will probably work, but I do not see it as a
requirement that we should take for granted. For example, I would not
submit it as a bug (unless I find a way to fix it first).

Thanks.