Resolving Django Migration Dependencies Across Multiple Devices

You're encountering a common issue with Django migrations when working across different environments. The problem occurs because your api.0001_initial migration has a dependency on a specific Django auth migration (auth.0012_alter_user_first_name_max_length) that exists in one environment but not in another.

The Root Cause

As you correctly identified, this happens because:

1. On your primary computer, you have a newer version of Django with more auth migrations
2. On your second machine, you have a different Django version with fewer auth migrations
3. Your custom migration references a specific auth migration that doesn't exist on the second machine

Solutions

Option 1: Ensure Consistent Django Versions

The most straightforward solution is to ensure both environments use the same Django version:

BASHCopied
# Pin the exact Django version in your requirements.txt
Django==5.1.0  # Replace with your specific version

Then reinstall dependencies on both machines:

BASHCopied
pip install -r requirements.txt

Option 2: Update Your Migration Dependencies

If you need to support multiple Django versions, you can modify your migration to reference an earlier auth migration that exists in all versions:

1. Find the earliest common auth migration across your environments
2. Edit your api/migrations/0001_initial.py file to update the dependencies:

PYTHONCopied
class Migration(migrations.Migration):
    dependencies = [
        # Replace this specific migration with an earlier one that exists in all environments
        ('auth', '0001_initial'),  # Use the earliest common migration
        # Other dependencies...
    ]
    
    operations = [
        # Your migration operations...
    ]

Option 3: Recreate Your Initial Migration

If your project is still in development and you can reset migrations:

1. Delete your existing migrations
2. Make sure both environments have the same Django version
3. Regenerate migrations with python manage.py makemigrations

Best Practices for Future Development

1. Pin exact Django versions in your requirements.txt to avoid version discrepancies
2. Include migration dependencies properly when accessing models from other apps
3. Be cautious when changing dependencies mid-project, as it can lead to complex issues

Remember that migrations create dependencies between apps, especially when you have relationships like ForeignKey between models in different apps. Django will try to ensure these dependencies are respected during migration execution.