Changes in Meta class are not detected after "makemigrations"

[Manuel Kaufmann]

I found that adding "permissions" to the Meta class into a model and then removing these Meta class makes django migration system to be confused and it tries to create a new migrations with an empty "options" dictionary each time that "makemigrations" is ran.

Steps to reproduce:

1. Create a new project
2. Create a new app
3. Install the app in the project
4. Run "migrate"
5. Create a new model

   class MyModel(models.Model):
       name = models.CharField(max_length=32)
   

6. Run "makemigrations"
7. Run "migrate"
8. Add Meta class to MyModel

   class MyModel(models.Model):
       name = models.CharField(max_length=32)
   
       class Meta:
           permissions = (
               ('use_mymodel', 'Use this model'),
           )
   

9. Run "makemigrations" and you will get the "options" attribute in the migration file

   operations = [
           migrations.AlterModelOptions(
               name='mymodel',
               options={'permissions': ((b'use_mymodel', b'Use this model'),)},
           ),
       ]
   

10. Run "migrate"
11. Remove Meta class from MyModel

    class MyModel(models.Model):
        name = models.CharField(max_length=32)
    

12. Run "makemigratios" and you will get an empty "options" dictionary

    operations = [
            migrations.AlterModelOptions(
                name='mymodel',
                options={},
            ),
        ]
    

13. Run "migrate"
14. Run again "migrate" and you will get this message:

    Your models have changes that are not yet reflected in a migration, and so won't be applied.
    Run 'manage.py makemigrations' to make new migrations, and then re-run 'manage.py migrate' to apply them.
    

15. Run "makemigrations" again and the same migration file is created with empty "options" dictionary

    class Migration(migrations.Migration):
    
        dependencies = [
            ('myapp', '0002_auto_20140807_1242'),
        ]
    
        operations = [
            migrations.AlterModelOptions(
                name='mymodel',
                options={},
            ),
        ]
    

Now, every time you run "migrate" it will tells you that "your models have changes that are not yet reflected in a migration" and after running "makemigrations" you will get the same migrations every time. So, you never get to a state valid for Django Migration System.

I'm attaching a project with all the steps already done, from where you just simply can run "migrate" and "makemigrations" many times to see what I described here.

[Manuel Kaufmann]

Project to reproduce this issue

[Areski Belaid]

It seems to affect django-1.7-rc-2.
I tested this with last django master (​https://github.com/django/django/commit/f9f9f3ad6073c353af924ed90c9386efd7bde8ac) and the bug seems to be solved.

@humitos, could you retest on master?

[Baptiste Mispelon]

I bisected the issue and found that it was fixed in 394053ce605a30c742d6270a80986b255adb3a30.

Thanks for doing the legwork on this.

[Manuel Kaufmann]

Replying to areski:

@humitos, could you retest on master?

Yes, thanks. It's working on "master". I got confused about the version I was using. Actually, I was using 1.7c2 to be specific.