dh_python2 and /usr/share/pyshared in quantal

[Barry Warsaw]

On May 22, 2012, at 10:49 AM, Scott Kitterman wrote:

>In https://launchpad.net/ubuntu/+source/python-defaults/2.7.3-0ubuntu3 Ubuntu 
>modified dh_python2 to drop creation of /usr/share/pyshared and creation of 
>python version specific symlinks to /usr/lib/python2.7/dist-packages/.
>
>I believe this change should be reverted, but rather than just upload, wanted 
>to discuss it first.  See https://bugs.launchpad.net/ubuntu/+source/python-
>defaults/+bug/1001912 for additional discussion.
>
>I've checked with Piotr Ożarowski (POX), the upstream developer for
>dh_python2 and he does not support removing this feature of dh_python2 until
>after pysupport and pycentral are removed.  Even with a single supported
>python version (as Ubuntu has now) it's still useful because pysupport
>installs files in the same location.  It avoids some namespace issues.
>
>This change breaks dozens of packages and has negligible (if any) advantages.
>
>Additionally, the Python policy lists /usr/share/pyshared as the correct
>location to install version independent python files, so removing it moves
>away from the documented policy.
>
>I'd like to understand if there's some compelling reason to make this change
>for quantal.  If not, it should be reverted sooner rather than later as
>packages built with this version are being misbuilt.

According to this message in the bug:

https://bugs.launchpad.net/ubuntu/+source/python-defaults/+bug/1001912/comments/2

Matthias made the change to try to catch unnecessary (invalid?) uses of
pyshared, which might a worthy goal if the package is not using
python-{support,central}.

For example, I took a look at authres which uses dh_python2.  debian/rules
creates a symlink in pyshared to its test suite, and then
d/python-authres.install references pyshared.  Even after reading the
changelog entry, it's not clear to me why this particular solution was chosen.
Fortunately the maintainer is here and can probably answer that <wink>.

I'm sympathetic to Matthias's goal to stop using pyshared, and I think his
intent was to use this change to gather information rather than use the
breakage to force the package maintainers to change their packages (or for
Ubuntu to carry deltas in all the packages).  Julian's list seems like a good
first cut on that information gathering:

https://launchpadlibrarian.net/105736622/pyshared

So it probably makes the most sense at this point to file bugs against each of
these packages in Ubuntu and Debian (assuming we're not carrying a dh_python2
delta, which would be a separate report in itself), and then revert the change
to unbreak the packages.

Either that or we have to commit to fixing each of the packages in Ubuntu, but
I agree that it seems like a lot of work for not much gain.

Cheers,
-Barry