Re: seeking advice for xcb-proto packaging
* Julien Cristau [Tue, 04 Nov 2008 18:43:28 +0100]:
> Hi,
Hello Julien,
> xcb-proto upstream installs a few python files[1], which are then used
> at build time by libxcb[2]. Using the upstream build system, these
> files get installed to $prefix/lib/python2.5/site-packages/xcbgen, and
> that path is set in xcb-proto.pc's pythondir variable. The libxcb build
> then uses that variable to look for xcbgen[3,4].
> Now that seems bad to me, because it means the python version gets
> hardcoded in the pkgconfig file, and when we switch to python 2.6
> c_client.py will still look in the python2.5 dir, and presumably find
> the .pyc files there. Can anyone here suggest a way to fix this, either
> by working around it in the packaging or as a patch that I could send
> upstream? python is very much an unknown beast to me, so hopefully
> you'll have some ideas :)
> Note that none of this is in the debian xcb-proto and libxcb packages
> yet, but I'm looking at packaging the next version and this issue is
> sort of blocking progress.
Let's go one step at a time:
(1) You should of course use python-central or python-support so that
the "xcbgen" Python package is always available for all installed
python versions. Hope that was your intention. :-)
(2) If you do that, then AFAICS no more meddling is strictly required for
things to work: the -p argument of c_client.py only appends the given
path to the list of directories Python searchs for modules. Since it
is appended at the end, the correct directory will be searched first.
(3) The fact that xcb-proto.pc hardcodes a Python path is, uhm, bad.
xcb-proto instalation script should take care of installing the Python
files somewhere importable (e.g. the $prefix/lib/python2.5/... path
you mentioned), and assume the 'import xcbgen' statement in c_client.py
will work in any system with xcb-proto installed (the -p flag could
still be supported, that's orthogonal).
Putting a Python path in the .pc file means xcb-proto has to be
recompiled whenever the default Python version changes. Maybe somebody
on the list can take care of educating upstream about this, if this
analysis is correct, which I believe it is.
Was that clear enough? :-)
> [1] http://cgit.freedesktop.org/xcb/proto/tree/xcbgen
> [2] http://cgit.freedesktop.org/xcb/libxcb/tree/src/c_client.py
> [3] http://cgit.freedesktop.org/xcb/libxcb/tree/configure.ac#61
> [4] http://cgit.freedesktop.org/xcb/libxcb/tree/src/Makefile.am#265
--
Adeodato Simó dato at net.com.org.es
Debian Developer adeodato at debian.org
The true teacher defends his pupils against his own personal influence.
-- Amos Bronson Alcott
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