Re: Injecting versions of build-deps in the deps

[Colin Watson <cjwatson@debian.org>]

On Mon, Dec 03, 2007 at 06:38:20PM +0100, Julien Cristau wrote:
> On Mon, Dec  3, 2007 at 17:33:41 +0100, Josselin Mouette wrote:
> > Every successful call to pkg-config would fill in a file, let’s say
> > debian/pkgconfig.deps, that would in the end contain:
> > 
> >         # pkgconfig_file required_version dev_package shared_package
> >         version
> >         x11 1.0.2 libx11-dev libx11-6 2:1.0.3-7
> >         gtk+2.0 2.8 libgtk2.0-dev libgtk2.0-0 2.12.2-1
> >         gconf 2.0 libgconf2-dev libgconf2-4 2.20.1-1
> > (The package version is needed because you need to extract epochs.)
> > 
> > In the end, shlibs generation would be able to generate the correct
> > dependency, based on the highest of the three versions:
> >      1. the version required by upstream;
> >      2. the version required by the build-deps;
> >      3. the version generated by the symbols file.
> > 
> > Plus, in this specific case, it would make the build fail because the
> > Debian maintainer has forgotten to bump the libx11-dev build-dependency
> > to 2:1.0.2, which is deadly useful information.
> 
> Why would you depend on any particular version of libx11-6?  The
> build-dep on libx11-dev >= 1.0.2 I can understand, but the runtime
> dependency has nothing to do with this.

For those of us less familiar with X, could you clarify why you wouldn't
want a run-time dependency if the upstream configure.ac says
PKG_CHECK_MODULES(FOO, x11 >= 1.0.2)? That is, what might they need at
build-time that they wouldn't need at run-time?


I like Loïc's idea in general; I know that build-time and run-time
dependency versions are conceptually distinct but they're not entirely
unrelated either. Raphaël's recent changes to dpkg-gencontrol to
simplify dependencies also help by making it straightforward to add an
explicit dependency in debian/control without worrying about whether
people are going to file bugs due to a duplicated dependency.

I wonder if the objections raised to this suggestion could be addressed
by making it optional in some way - perhaps either by requiring it to be
manually enabled for each library by some kind of shlibs/symbols-like
system, or by providing support for libraries to declare themselves
exempt from it.

-- 
Colin Watson                                       [cjwatson@debian.org]