Re: Injecting versions of build-deps in the deps

[Loïc Minier <lool@dooz.org>]

On Fri, Dec 07, 2007, Colin Watson wrote:
> 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.

 I do imagine it wont be mandatory (or useful) for all libs as well and
 I agree it should be added on a per package basis; one idea I
 mentionned to Raphaël is to extend the shlibs / symbols system to allow
 a syntax meaning "Take the build-dep version" instead of having a fixed
 version; that is, instead of:
    libgtk-x11-2.0 0 libgtk2.0-0 (>= 2.12.0)
 we might have some macros like:
    libgtk-x11-2.0 0 libgtk2.0-0 (>= $Build-Depends{libgtk2.0-dev})

 Can be seen as "dynamic shlibs" or "shlibs macros".  (Or symbols.)

 [ NB: this is overly simplistic as a package can have duplicate
      build-depends like libgtk2.0-dev >= 1, libgtk2.0-dev >= 2, or
      libgtk2.0-dev << foo, and there are build-conflicts and
      build-deps-indep as well ]



 In the last week, I came up with many crackful ideas which most people
 should ignore for the time being, but which some will find funny:
   instead of defining a complex syntax, we could as well allow for
 dpkg-shlibdeps to be extended to call some hook when a particular
 SONAME dep is encounted.  Some kind of plugins mechanisms to allow some
 specialized code provided by the libfoo maintainer to be run when a
 libfoo dep is encountered.

   This code could be based on API provided by dpkg-shlibdeps for most
 things.  The plugin interface could be as simple as:
    onShlibDep($needed, $pathname) {};

 with libgtk2.0-dev declaring in shlibs:
    libgdk-x11-2.0 0 run:gtk-shlibdep
 or:
    dynshlibs: libgdk-x11-2.0 0 gtk-shlibdep

 implemented as:
    onShlibDep($nedeed, $package, $pathname) {
        my $ver = getBuildDepsVer("libgtk2.0-dev");
        addDepends($package, "libgtk2.0-0 (>= $ver)");
    };

 Concrete advantage over the non-crackful idea?  I guess none at the
 moment, but yours to imagine!

-- 
Loïc Minier