ValueError：南部模式迁移和数据迁移的日期超出月份范围

Question

TL;DR: Has anyone ever seen schemamigration and datamigration fail with south v. 0.8.4 raising a ValueError: day is out of range for month?

I'm working on a rather large application that's got a lot of developers working at the same time - so chances are that this is something much more complicated and I'm limited in what I can share in terms of source code, so apologies to all for the cruddily-formed question. I needed to update a CharField to increase its max length, and just like yesterday I ran:

python manage.py schemamigration <appname> update_char_field_ length --auto

and while it worked yesterday to create the relevant table, today I get:

ValueError: day is out of range for month

with no traceback info at all.

So for giggles I ran ... datamigration <appname> test --stdout and get the same. I was wondering if anyone has run into this before, or if not, does anyone know of a way to get south's datamigration to operate more verbosely so I might be able to trace this down in source faster?

What's weird is that I've rolled back the changes in git to a couple of days ago and reloaded the database snapshot from scratch and still get the error.

Answer 1

This actually probably doesn't have to do with your code per se as much as it has to do with Today's date! Somewhere you're trying to get a date that doesn't exist.

One example would be if there is logic somewhere to get the last day of previous month and the code is looking for the 31st of June, which doesn't exist.

Without being able to share code it's impossible to see where that's happening, but hopefully that points you in the right direction.

Answer 2

Closing the issue - for anyone who might look at this, it did indeed have to do with the fact that it's the first of the month. The problem lived in one of the functions that populates default values while generating the migration files, it was just a matter of digging through source code until I could find it...