Django: Best way to merge migrations conflicts

user_7692463 0
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I'm currently working on a dev branch and I will need to merge it to master one day. I have up to 20 migrations files on my dev branch and about the same number on master at the moment. I needed to make migrations on both branches which will result in migrations having the same prefix,

(ex 0003_auto)

In other words, if you have migrations files generated by makemigrations with the same prefix, what is the best/secure way of handling this.

Here are two ways I have figured myself (maybe entirely wrong):

  1. Deleting all migrations files, merge the code and then running a fresh makemigrations and migrate which will result in only one migration file.

  2. Using the --merge flag to let django make the merge:

    makemigrations --merge

Now, knowing all this I'd like to know what is the best way of handling this. In general, what should I use that will correctly merge conflicts and get me a fresh version of my project with every model updates.

EDIT

I think providing a step by step solution would be ideal for me and future users since there exists tons of informations on the subject but not one seems to be concise and clear.

django-migrations django python
4 Answers

From the Django docs:

Because migrations are stored in version control, you’ll occasionally come across situations where you and another developer have both committed a migration to the same app at the same time, resulting in two migrations with the same number.

Don’t worry - the numbers are just there for developers’ reference, Django just cares that each migration has a different name [emphasis added].

user_16620310

The simplest way to do this without any worry is this:

  1. Revert to a stable point (before conflicts):

python manage.py migrate usersmaster 0021_signup_status

  1. Delete new migration files.

  2. Re-make migrations:

python manage.py makemigrations

user_24199600

When you are ready, you should merge from master to your development branch. At that time you should fix all conflicts, your migrations should go after master's migrations, and after all of that your database should look as you want it be like.

Since that process takes time, and is quite painful, most people consider short living development branches. That way you need to deal with one or two migration files at a time.

user_61030010

You can resolve migration errors using django-migration-fixer

Fixing migrations on your dev branch can be done using

$ git checkout [dev-branch]
$ git merge [main/master]

Follow the installation instructions here

Run

$ python manage.py makemigrations --fix -b [main/master]

commit the changes and push to the remote branch

$ git add .
$ git commit -am ...
$ git push ...
user_45846720
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