Migrating easy_thumbnails within Django upgrade from 1.6.7 to 1.7.1

Question

I'm trying to upgrade from Django 1.6.7 to 1.7.1

However, after upgrading the Django version in my local virtualenv and all my own Django apps (for which the new migrate works), I cannot get migrate for the easy_thumbnails app (version 2.2) to work. This version should work properly with the new migrations system (post South) in Django 1.7 (instructions here).

As far as I can tell, the reason is that the second migration in the easy_thumbnails app is trying to recreate the migration (source code here).

But naturally, since this code is intentionally there by the package authors, I'm afraid am doing something wrong myself.

Any ideas what the cause of this is?

Full stack trace:

./manage.py migrate easy_thumbnails --settings=[my.settings.module]
Operations to perform:
  Apply all migrations: easy_thumbnails
Running migrations:
  Applying easy_thumbnails.0002_thumbnaildimensions...Traceback (most recent call last):
  File "./manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 160, in handle
    executor.migrate(targets, plan, fake=options.get("fake", False))
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 63, in migrate
    self.apply_migration(migration, fake=fake)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 97, in apply_migration
    migration.apply(project_state, schema_editor)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/migrations/migration.py", line 107, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/migrations/operations/models.py", line 36, in database_forwards
    schema_editor.create_model(model)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/schema.py", line 263, in create_model
    self.execute(sql, params)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/schema.py", line 99, in execute
    cursor.execute(sql, params)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 81, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: relation "easy_thumbnails_thumbnaildimensions" already exists

Answer 1

The problem above was fixed by following these steps.

1. Revert to the previous Django version (1.6.7) within the virtual env
2. Revert to previous code version (with South migrations, not Django migrations)
3. Revert the last applied easy_thumbnails migration (migration 0016) using the command below:

python manage.py migrate easy_thumbnails 0015 --settings=[your.settings.module]
 - Soft matched migration 0015 to 0015_auto__del_unique_thumbnail_name_storage_hash__add_unique_thumbnail_sou.
Running migrations for easy_thumbnails:
 - Migrating backwards to just after 0015_auto__del_unique_thumbnail_name_storage_hash__add_unique_thumbnail_sou.
 < easy_thumbnails:0016_auto__add_thumbnaildimensions

4. Restore Django 1.7.1 (using pip install Django==1.7.1) within the virtual env
5. run the new migrate; should work now