[debian-mysql] Bug#671115: Bug#671115: transition: mysql-5.5

[Clint Byrum]

Excerpts from Adam D. Barratt's message of Sat May 19 08:51:34 -0700 2012:
> On Tue, 2012-05-08 at 06:18 -0700, Clint Byrum wrote:
> > On May 8, 2012, at 2:04, Julien Cristau <jcristau at debian.org> wrote:
> > > On Tue, May  1, 2012 at 22:52:22 +0100, Nicholas Bamber wrote:
> > >> At some point we need to transition from mysql-5.1 to mysql-5.5. We
> > >> would like to do this before the freeze though we appreciate that time
> > >> is now short. We arrived at this position as the Debian MySQL Team became
> > >> increasingly understaffed. It is better now but not ideal.
> [...]
> > To be fair, this transition was already completed in Ubuntu and I
> > filed bugs against all packages that failed with patches. Most if not
> > all of these patches have been applied.
> > 
> > I would expect this transition to go quite smoothly and just to
> > require rebuilds given the  experience we had in Ubuntu.
> 
> The problem is that the recent set of php5 security updates are
> currently stuck in unstable, because they picked up a dependency on
> libmysqlclient18.
> 
> For most library transitions, this wouldn't be such a big problem as we
> could push the new version of the source in and have britney keep the
> old library around in testing for as long as there were
> reverse-dependencies; indeed there was some hope that with mysql-5.5
> being a separate source package, this would be even easier as the two
> source packages could co-exist.
> 
> However, it turns out that won't work - the 5.5 packages have:
> 
> Breaks: mysql-client-5.1 (<< 5.5), mysql-server-5.1 (<< 5.5),
> mysql-server-core-5.1 (<< 5.5)
> 
> and there are no versions of those packages with versions >= 5.5 (so I'm
> not entirely sure what the logic behind the version constraints is).
> Various -5.1 packages have versioned dependencies on other binaries from
> that source, which means we can't even mitigate the problem by adding
> Provides from the 5.5 packages.  Providing them as real transitional
> packages from the 5.5 source would probably work, unless there's some
> reason that's a crazy suggestion?
> 
> (There's also a mysql-5.1 upload which can't migrate to testing, as
> britney is convinced that it needs mysql-5.5 to migrate first;
> presumably because the latter now provides the
> mysql-{client,common,server} binary packages in unstable.)
> 


I've done some testing on this. The piece of my.cnf that I thought
would break client and libmysqlclient does not. It only breaks
mysql-server-core-5.1:

120525  0:20:34 [ERROR] mysqld: unknown variable 'lc-messages-dir=/usr/share/mysql'

So the Breaks: on 5.5's mysql-common can be dropped to just

Breaks: mysql-server-5.1, mysql-server-core-5.1

It seems to me that this plan will let things migrate into testing at
that point:

* Upload mysql-5.1 with all unversioned and server packages removed:
  libmysqlclient-dev
  libmysqld-dev
  libmysqld-pic
  mysql-server
  mysql-server-5.1
  mysql-server-core-5.1
  mysql-client
  mysql-testsuite
* Upload mysql-5.5 (5.5.24 is out and fixes a security flaw)  with the
Breaks: on mysql-comon relaxed as above.

This should allow us to progress 5.5 into testing without making anything
uninstallable except mysql-server-5.1, and mysql-server-core-5.1. Users
who have those installed *should* get 5.5 as an upgrade since it
breaks/replaces the -5.1 packages. Their only rdepends in unstable are:

pvpgn - suggests only
|python-mysqldb - suggests, optional 'mysql-server'
mahara - recommends, optional 'mysql-server'

I am still very new to the Debian release process though, so please do
educate me on reasons this would be a bad idea, assuming 5.5 is ready
to migrate to testing.