Removing a Django migration that depends on custom field from an old module

Question

I have a Django 1.8 application whose initial migration relies on django-interval-field like this:

import interval.fields

migrations.CreateModel(
    name='Item',
    fields=[
        ...
        ('estimated_time', interval.fields.IntervalField(null=True, blank=True)),

I've since migrated this field to use Django's built-in DurationField, and I'm not using this module anymore, but I need to keep it in requirements.txt in order for my migrations to run.

However, this module throws errors when trying to upgrade to Django 1.9. In addition, I can't keep this module around forever. It would be nice to get rid of it.

I've tried squashing the migrations, but the squashed migration still contains the import interval.fields statement, and creates the interval field. All squashing does is concatenate everything into one file.

Can someone tell me how to go forward towards removing this module?

The Django app in question is here.

Answer 1

So, your squashing is not true squashing

1. Remove this package from requirements.txt
2. Remove import interval.fields from your models.py
3. Modify your interval.fields.IntervalField(xxx) to some type available in Django in the related my_app_label/migrations/1234_some_migrations.py
4. Done