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
28073	RemoveField.state_forwards() crashes with AttributeError: 'NoneType' object has no attribute 'is_relation'	Logan Gunthorpe	Pallav Parikh	"Hi,

I'm trying to upgrade my project (originally created on 1.7) to the latest release but there's an issue with my existing migration files not working. The backtrace is below.

I'll attache my migration files but it seems to be related to the migration removing the 'id' field which was automatically created and then removed in a future migration. Commenting out the RemoveField in the second migration seems to fix the issue but I'm not sure if it's entirely correct to do so.

Thanks,

Logan




{{{
Traceback (most recent call last):
  File ""./manage.py"", line 10, in <module>
    execute_from_command_line(sys.argv)
  File ""/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site-packages/django/core/management/__init__.py"", line 363, in execute_from_command_line
    utility.execute()
  File ""/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site-packages/django/core/management/__init__.py"", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File ""/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site-packages/django/core/management/base.py"", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File ""/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site-packages/django/core/management/base.py"", line 330, in execute
    output = self.handle(*args, **options)
  File ""/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site-packages/django/core/management/commands/migrate.py"", line 163, in handle
    pre_migrate_state = executor._create_project_state(with_applied_migrations=True)
  File ""/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site-packages/django/db/migrations/executor.py"", line 81, in _create_project_state
    migration.mutate_state(state, preserve=False)
  File ""/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site-packages/django/db/migrations/migration.py"", line 92, in mutate_state
    operation.state_forwards(self.app_label, new_state)
  File ""/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site-packages/django/db/migrations/operations/fields.py"", line 148, in state_forwards
    delay = not old_field.is_relation
AttributeError: 'NoneType' object has no attribute 'is_relation'

}}}


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