Migrations fail when change upload_to from function to sting type

[argaliev]

In first migration function make_upload_path was passed to upload_to property of FIleField:

def make_upload_path(instance, filename):
    return 'auto_scripts/{0}/{1}'.format(instance.id,filename)

class file_imports(models.Model):
    orig_file = models.FileField(upload_to=make_upload_path, blank=True, null=True)

Then upload_to was changed to hardcoded string and function make_upload_path was deleted.

orig_file = models.FileField(upload_to='auto_scripts/', blank=True, null=True)

and getting following error when starting makemigrations:

......
File "...../main/migrations/0001_initial.py", line 108, in Migration
    ('orig_file', models.FileField(upload_to=main.models.make_upload_path, null=True, 
AttributeError: 'module' object has no attribute 'make_upload_path'

Looks like migrations still want to see old function make_upload_path in code, but it does't need anymore.

[Tim Graham]

You need to keep the make_upload_path() function around as long as it's referenced in migrations. See ​https://docs.djangoproject.com/en/stable/topics/migrations/#historical-models.