Files deleted by Django Migrations

Question

I’m having a constant problem. As I am working with several branchs in a project, sometimes I go back in an old branch, bring updated branch to the old one so I don’t have to keep creating old bank Migration. Only every time of the problem with Migrations. Sometimes it gives an absurd error and I delete everything, Migrations, base and recomeco. It works, only then the files of Migration are different. So when I will migrate the error because this missing file or dependency.

I would like to understand the process I have to do to avoid or solve these problems. Remembering that I have an environment in production, that even not available to the user, probably can happen this type of problem.

In my case, that’s the problem:

django.db.migrations.exceptions.NodeNotFoundError: Migration comunidade.0011_auto_20170608_1556 dependencies reference nonexistent parent node ('comunidade', '0010_auto_20170605_1809')

When I enter the file, it has a dependency for the file:

0010_auto_20170605_1809

However you do not have this file. It has probably been deleted or something like that. I could try switching manually to the last file, the 0002_auto_20170621_1721. However, he has the validation in the bank, I think is not ideal.

I tried to do zero migrate, but the error keeps giving. I did a --fake (which I’ve been told is pork) and nothing.

I need some hint. I’m using Django 1.10 and Python 3.4

Answer 1

Problems with Migrations are very common in the Django universe, as I have seen reports that in complex scenarios some teams prefer to create mechanisms to disable migrations. After some time of "suffering" and a lot of research in the intenet, I ended up creating a script to "reset" the migrations, I will reproduce the steps below (my environment is linux):

1) Clear the history for all apps, the example below clears the history of the core name app.

python manage.py makemigrations
python manage.py migrate --fake core zero

2) Remove the migration files:

find . -path "*/migrations/*.py" -not -name "__init__.py" -delete
find . -path "*/migrations/*.pyc"  -delete

3) Create the initial migrations:

$ python manage.py makemigrations
$ python manage.py migrate --fake-initial

Now give a showmigrations and see that everything is ok.

My strategy:
I put that commands in a file and run it every time I deploy, output copy for staging or staging to the location.