Code review comment for lp:~sylvain-legal/openupgrade-server/three-functions-for-addons-migration

Lacking the cleanup module, I think this function is very useful. But shouldn't it be able to figure out by itself where the field come from now?

I'd much prefer actually to have the cleanup module and a function that allows us to add messages to the administrator with a severity on a per module, model and field level.

How about the compromise: Write this function first, what it currently does is write into the log, and some time in the future to the cleanup-module's messages table?