[Maas-devel] Database Migrations and backports

[Julian Edwards]

Hi all

There's something that Raphaël said to me last week about database migrations 
that I wanted to make people more widely aware of.

Each South migration contains the complete state of the database schema at 
that time, which has a couple of important ramifications:

 * We must be very careful when adding new migrations that nobody else is 
working on one too, because one of you must base your migration off the 
other's

 * When amending old release branches (e.g. lp:maas/1.2) we *cannot* add new 
migrations to it on their own, we *must* add it to trunk and backport all the 
missing trunk migrations.  If this is not done, it will break upgrades between 
releases.

So, please be very careful when adding database migrations.

Cheers.