2.3/Sid release engineering (was Re: Missing autoconf build-dependancy in cyrus-imapd-2.3 branch ?)

[Henrique de Moraes Holschuh]

On Mon, 29 Jun 2009, Benjamin Seidenberg wrote:
> I'd like to see a bit more research on the issue to be comfortable, to
> make sure this is true in all cases, not just the case on your server.
> 
> Sven Mueller wrote:
> > For the record:
> > Upgrading Berkeley DB files from 4.2 to 4.7 doesn't change the DB file
> > (or any other file in the directory, including subdirectories, for that
> > matter). So we could simply s/BerkeleyDB4.2/BerkeleyDB4.7/ on
> > /usr/lib/cyrus/cyrus-db-types.active on upgrades.

As Benjamin said, this is risky.  I vote for a simple solution such as
"backup files to somewhere (or add .debian-db-upgrade-bkp suffix, etc), then
run db<foo>_upgrade, and after it all, update the .active file.

Such a solution:

1. Is safe even if BDB changes something only on a certain arch on a certain
endianness, which is something *we* are not going to know about until it
hits someone;

2. Is generic and will work for the future too;

3. Allows downgrading, through manual intervention which can be described in
a README file.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh