Partial dh_python2 transitions

[Martin Pitt]

Hey Mike,

Michael Terry [2011-06-16 11:17 -0400]:
> Hello!  I was just considering how a dh_python2 transition for the
> various ubuntuone python modules would work.  They all install into
> the ubuntuone module, so would need to be updated at the same time.
> 
> Is there a recommended way to avoid the problem of users partially
> upgrading (either from builds finishing separately or specifically
> apt-get installing only some of the packages) and having mixed tool
> usage?

We (as in pkg-gnome) indeed had the very same problem for pygobject,
gnome-python, and various other packages, which install/share a
"gtk-2.0" sub-namespace. What I did was:

  * debian/rules: Install a library search path for a pysupport compatible
    gtk-2.0 directory, to avoid instantly breaking all reverse dependencies.
    This needs to stay until they get converted to dh_python2.

in debian/rules:

        # until all reverse dependencies of pygobject have been converted to
        # dh_python2, install a library search path which is backwards
        # compatible to pysupport (see Debian#614764)
        echo "/usr/lib/pymodules/python$*/gtk-2.0/" > $(CURDIR)/debian/python-gobject-dev/$(call py_libdir_sh, $*)/gtk-2.0-pysupport-compat.pth

With this search path, a gtk-2.0 submodule can be in either
/usr/lib/pymodules/python2.7/gtk-2.0 (pysupport) or
/usr/lib/python2.7/dist-packages/gtk-2.0 (dh_python2/upstream python).

It's a hack, but we considered it good enough, and much better than
having to transition some 10 packages in lockstep.

Martin

-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)