id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
28084	FieldDoesNotExist when running a migration that removes a deleted field from unique_together	Bas ten Berge	nobody	"Hi,

I'm running into an issue when performing this change to this model:


{{{
class TopicOwnerThoughtStatus(models.Model):
    '''
    Registers topic owner stats

    '''
    thought = models.ForeignKey(Thought, help_text='Associates the state to a thought', db_index=True)
    user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='topicownerstatus_set', help_text='Associates this state to an user')
    topic = models.ForeignKey(Topic, help_text='Associates this state to a thought and topic')
    notified_at = models.DateTimeField(null=True, blank=True, help_text='Contains the timestamp the topicowner was notified')
    shown_at = models.DateTimeField(null=True, blank=True, help_text='Contains the timestamp the topicowner viewed the thoughts')
    finished_at = models.DateTimeField(null=True, blank=True, help_text='Contains the timestamp the topicowner marked the topic closed')

    class Meta:
        unique_together = ('thought', 'user', 'topic', )
        ordering = ('thought', )
        verbose_name_plural = 'Topic owner status'
}}}

Changing this model to: 
{{{
class TopicOwnerThoughtStatus(models.Model):
    '''
    Registers topic owner stats

    '''
    thought = models.ForeignKey(Thought, help_text='Associates the state to a thought', db_index=True)
    user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='topicownerstatus_set', help_text='Associates this state to an user')
    topic_selector = models.CharField(max_length=36, null=True, blank=True, help_text='Contains the topic selector')
    notified_at = models.DateTimeField(null=True, blank=True, help_text='Contains the timestamp the topicowner was notified')
    shown_at = models.DateTimeField(null=True, blank=True, help_text='Contains the timestamp the topicowner viewed the thoughts')
    finished_at = models.DateTimeField(null=True, blank=True, help_text='Contains the timestamp the topicowner marked the topic closed')

    class Meta:
        unique_together = ('thought', 'user', 'topic_selector', )
        ordering = ('thought', )
        verbose_name_plural = 'Topic owner status'

}}}

will allow me to create a migration, but I'm not able to run that migration:
{{{
(env-brownpapersession)bastb@bastb-vps:/var/www/brownpapersession/dev/brownpapersession$ python manage.py migrate                                            Operations to perform:
  Apply all migrations: ..., topic
Running migrations:
  Applying topic.0014_auto_20170417_0941...Traceback (most recent call last):
  File ""manage.py"", line 10, in <module>
    execute_from_command_line(sys.argv)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/core/management/__init__.py"", line 363, in execute_from_command_line
    utility.execute()
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/core/management/__init__.py"", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/core/management/base.py"", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/core/management/base.py"", line 330, in execute
    output = self.handle(*args, **options)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py"", line 204, in handle
    fake_initial=fake_initial,
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/db/migrations/executor.py"", line 115, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/db/migrations/executor.py"", line 145, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/db/migrations/executor.py"", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/db/migrations/migration.py"", line 129, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/db/migrations/operations/models.py"", line 536, in database_forwards
    getattr(new_model._meta, self.option_name, set()),
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/db/backends/base/schema.py"", line 348, in alter_unique_together
    self._delete_composed_index(model, fields, {'unique': True}, self.sql_delete_unique)
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/db/backends/base/schema.py"", line 371, in _delete_composed_index
    columns = [model._meta.get_field(field).column for field in fields]
  File ""/var/www/brownpapersession/dev/env-brownpapersession/local/lib/python2.7/site-packages/django/db/models/options.py"", line 619, in get_field
    raise FieldDoesNotExist(""%s has no field named '%s'"" % (self.object_name, field_name))
}}}

I'm able to run this migration when following a two-step approach: 
* add the topic_selector field 
* change the unique_together to read ('thought', 'user', 'thought_selector', )
* create and run the migration
* remove the topic field
* create and run the migration

I'd expect to run this in one migration, though.
"	Bug	closed	Migrations	1.11	Normal	duplicate			Unreviewed	0	0	0	0	0	0