python - Django: dependencies reference nonexistent parent node

52
votes

When I run the following command

python manage.py migrate

I receive this error from django so can't step forward in my practice:

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/home/nikhil/testWeb-devEnv/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 "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 63, in handle
    executor = MigrationExecutor(connection, self.migration_progress_callback)
  File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 17, in __init__
    self.loader = MigrationLoader(self.connection)
  File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/db/migrations/loader.py", line 48, in __init__
    self.build_graph()
  File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/db/migrations/loader.py", line 241, in build_graph
    self.graph.add_dependency(migration, key, parent)
  File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/db/migrations/graph.py", line 42, in add_dependency
    raise KeyError("Migration %s dependencies reference nonexistent parent node %r" % (migration, parent))
KeyError: u"Migration testBolt.0001_initial dependencies reference nonexistent parent node (u'delivery_boy', u'0004_auto_20150221_2011')"

How do I solve this problem?

14
pythondjangomigrate
So, do you have a migration called 0004_auto_20150221_2011 in the delivery_boy app? - Daniel Roseman
There is no migration 0004_auto_20150221_2011 in my delivery_boy app. - NIKHIL RANE
Well, that explains the error, then. Now you need to remove that reference from frshBolt.0001_initial and investigate why you have that dependency in the first place. - Daniel Roseman
@DanielRoseman can you please add it as an answer so it can be accepted (and question resolved) ? - tutuDajuju
From the error message we can see that the error is caused by frshBolt.0001_initial dependencies. Removing frshBolt.migrations fixed the issue for me.. - SuperNova

14 Answers

53
votes

Solution - 1

Remove pyc files from your migrations folder.

Solution - 2

Need to remove that reference from testBolt.0001_initial by editing migration file.

Solution - 3

  1. Remove the new changes from the models and run python manage.py migrate --fake

  2. Now again modify your models with new changes

  3. Run python manage.py makemigrations

  4. And then again run python manage.py migrate

8
votes

I had the same problem. In my case, because I played with migrations manually, I forgot to create __init__.py inside of migrations folder.

8
votes

In my case, I had the .py extension in the dependency module name, like this:

dependencies = [
    ('dashboard', '0003_auto_20181024_0603.py'),
    ('auth', '__latest__'),
    ('contenttypes', '__latest__'),
]

I removed the .py, changing it to this

    ('dashboard', '0003_auto_20181024_0603')

and that fixed it.

6
votes

This works for me In your app migrations folder

  1. Delete all the files pyc in your app folder (except the __init__)

  2. Delete all the files in the migrations (except the __init__ )

  3. python manage.py makemigrations

  4. python manage.py migrate
  5. runserver
4
votes

I had a similar case, running django in windows in a virtual env. In my case the missing dependency was 0001_initial - which was definitely there in the migration folder.

The 'solution' was to remove the pyc files and do another migrate attempt.

4
votes
KeyError: u"Migration testBolt.0001_initial dependencies reference nonexistent parent node (u'delivery_boy', u'0004_auto_20150221_2011')"

Remove

testBolt.0001_initial

then run migrate again

3
votes

Make sure that you have activated your virtual environment.

3
votes

This worked for me:

  • Delete environment.
  • Crearte new environment with all dependencies
2
votes

I had moved around my virtual environment folder.so I moved it back where it was, worked for me.

2
votes

Here's how it worked for me:

  1. Deleted all the __pycache__ folders inside every app.
  2. Deleted all the files inside the migration folder except for __init.py__ inside each app folder.
  3. python manage.py makemigrations
  4. python manage.py migrate
  5. python manage.py runserver
1
votes

I tried NIKHIL's solutions with no luck. What did work for me was:

  • Removing my virtual environment
  • Deleting the migration __pycache__ folders
  • Deleting old migrations
  • Recreating my virtual environment
  • Running migrations
1
votes

I just uninstalled Django and reinstalled it:

pip3 uninstall Django

pip3 install Django

then migrated

0
votes

There could be some migration files remaining in the app when you tried the migrate command. First remove all migrations directories from all the modules. For other cases Nikhil Rane has covered it all.

-2
votes

Go to folder testBolt -> migrations and remove 0001_initial py and pyc files.