Bug#844725: libproj12 should conflict with libproj9

[Gianfranco Costamagna]

control: reopen -1

Hi Sebastiaan,

can we please keep it open for some days, to discuss it? :)
I don't feel confortable in writing to a closed bug ;)



>Sorry to hear you wasted your time. Thank for caring about packages in
>universe though, too few people in Ubuntu do.



not a problem, it wasn't wasted, but a good learning opportunity.
>Transitions ensure that all reverse dependencies are updated for the new
>library thereby making it obsolete and easy to remove with `apt-get
>autoremove`. By having all rdeps depend on the new library package, the
>old one should no longer be installed via (build) dependencies.


you can't force people to uninstall a library on their system, I had this issue
with libpng12, that is probably still installed on some Debian chroots (according to
the various binNMU requests in release.d.o, seems that even developers are not cleaning
their systems)

>The failure in Ubuntu to do a proj transition does not warrant an RC bug

>in Debian.

this isn't a failure in Ubuntu to transition proj, in fact I did it successfully.

>Conflicts are not appropriate because libproj9 and libproj12
>do not contain the same files

they are appropriate for my policy parsing:
https://www.debian.org/doc/debian-policy/ch-relationships.html#s-conflicts

Conflicts should be used
[...]
in other cases where one must prevent simultaneous installation of two packages for reasons that are ongoing (not fixed in a later version of one of the packages) or that must prevent both packages from being unpacked at the same time, not just configured.

>The fix for this issue is to do a proj transition in Ubuntu as we've
>done in Debian. If Ubuntu does not have the manpower to do transitions
>for packages in universe, they should consider removing those packages
>to acknowledge their lack of maintenance in Ubuntu. Removal of packages
>Ubuntu users rely on should motivate them to become involved in their
>maintenance in a similar fashion as removal from testing in Debian.


please don't blame Ubuntu, I'm discussing a totally different issue here.
Since you can't force people from not having two different incompatible libraries, at least
you should enforce python-pyproj in using the correct one, because as you can say there,
apt is not preventing usage of libproj9 together with python-pyproj and the wrong gdal binding.

this is the issue, the dependencies should have the correct relationships, to avoid such issues,
during upgrades or when people selectively picks what to keep and what to upgrade.

I hope it is clear now.

G.