Re: Dynamic package version numbers with Autoconf and Automake (was: Re: Automake 1.12.0b test release)

[Bob Friesenhahn]

On Wed, 15 Aug 2012, Stefano Lattarini wrote:
> > AM_INIT_AUTOMAKE($PACKAGE_NAME,"${PACKAGE_VERSION}${PACKAGE_VERSION_ADDENDUM}", 
> > ' ')
> >
> > The reason is because it avoids needing to edit configure.ac (a really stupid
> > practice)
> I agree with this; with today's DVCS, it's very tempting (and IMHO useful)
> to base a package's version number on the current revision number/SHA-1; so
> that the version is bound to change with every commit, and forcing a full
> re-autotooling + reconfiguration + rebuild of the package for every commit
> sounds just crazy.

Yes, and in your suggested scenario, it is not possible to edit a file 
without adding a new changeset (Catch-22).

> But then, I believe this is something that should to be fixed at the Autoconf
> level.  I.e., the version number shouldn't be hard-coded in the generated
> configure and config.status scripts, nor put in 'config.h' or other generated
> headers -- or at least, we should be able to tell Autoconf not do that, and
> how to fetch/define/compute the version number at runtime instead.

Agreed.

> > every time a new release tarball will be cut. Instead the version information
> > to apply is computed by a script which is sourced by configure.
> >
> > What is the workaround for this?
> Actually, it depends.  Where and why do you use such dynamically-computed
> version number in exactly?

A script ("version.sh") is executed in order to obtain the package and 
version information.  In the most common case, the version is a 
development "snapshot" and the version is based on the latest 
specified date in the ChangeLog file.  For formal releases, the 
version is hard-coded in the script.

Any time that 'make' is executed is a candidate time for the package 
version to be changed.  In the GraphicsMagick project, editing the 
top ChangeLog file causes configure to be re-executed (due to added 
rules). This assures that the version is always correct (at the 
expense of more compilation time).

Bob
--
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/