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
22344	Migration from ForeignKey to FileField fails: AttributeError: 'NoneType' object has no attribute 'to'	Daniel Hahler	nobody	"The following migration fails to change the ForeignKey field into a FileField:
{{{
        migrations.AlterField(
            model_name='mainfile',
            name='file',
            field=models.FileField(upload_to='...'),
        ),
}}}
{{{
  Applying app.0017_auto_20140326_1849...Traceback (most recent call last):
  File ""…/manage.py"", line 62, in <module>
    execute_from_command_line(sys.argv)
  File ""…/django-master/django/core/management/__init__.py"", line 427, in execute_from_command_line
    utility.execute()
  File ""…/django-master/django/core/management/__init__.py"", line 419, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File ""…/django-master/django/core/management/base.py"", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File ""…/django-master/django/core/management/base.py"", line 337, in execute
    output = self.handle(*args, **options)
  File ""…/django-master/django/core/management/commands/migrate.py"", line 145, in handle
    executor.migrate(targets, plan, fake=options.get(""fake"", False))
  File ""…/django-master/django/db/migrations/executor.py"", line 60, in migrate
    self.apply_migration(migration, fake=fake)
  File ""…/django-master/django/db/migrations/executor.py"", line 94, in apply_migration
    migration.apply(project_state, schema_editor)
  File ""…/django-master/django/db/migrations/migration.py"", line 97, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File ""…/django-master/django/db/migrations/operations/fields.py"", line 127, in database_forwards
    from_field.rel.to = to_field.rel.to
AttributeError: 'NoneType' object has no attribute 'to'

ipdb> from_model, from_field, from_field.rel, to_field, to_field.rel

<class '__fake__.MainFile'>,
<django.db.models.fields.related.ForeignKey: file>
<django.db.models.fields.related.ManyToOneRel object at 0x4385410>
<django.db.models.fields.files.FileField: file>
None)
}}}

"	Bug	closed	Migrations	dev	Normal	fixed			Accepted	0	0	0	0	0	0