Running migrations works locally but not on Travis CI - django

Question

I have a project in Django 1.8 and I'm starting to use Travis CI, but I have a problem that I cannot solve.
When I perform test locally, by python manage.py test, it works fine and there is no problem at running migrations. However, when the same command is executed by Travis, it applies well all migrations except one.
The error trace is the following:
Traceback (most recent call last):
File "EntHub/manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/__init__.py", line 338, in execute_from_command_line
utility.execute()
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/__init__.py", line 330, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/commands/test.py", line 30, in run_from_argv
super(Command, self).run_from_argv(argv)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/base.py", line 390, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/commands/test.py", line 74, in execute
super(Command, self).execute(*args, **options)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/base.py", line 441, in execute
output = self.handle(*args, **options)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/commands/test.py", line 90, in handle
failures = test_runner.run_tests(test_labels)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/test/runner.py", line 210, in run_tests
old_config = self.setup_databases()
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/test/runner.py", line 166, in setup_databases
**kwargs
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/test/runner.py", line 370, in setup_databases
serialize=connection.settings_dict.get("TEST", {}).get("SERIALIZE", True),
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/db/backends/base/creation.py", line 368, in create_test_db
test_flush=True,
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/__init__.py", line 120, in call_command
return command.execute(*args, **defaults)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/base.py", line 441, in execute
output = self.handle(*args, **options)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 221, in handle
executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/db/migrations/executor.py", line 110, in migrate
self.apply_migration(states[migration], migration, fake=fake, fake_initial=fake_initial)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/db/migrations/executor.py", line 147, in apply_migration
state = migration.apply(state, schema_editor)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/db/migrations/migration.py", line 115, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/db/migrations/operations/fields.py", line 201, in database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 469, in alter_field
return self._alter_many_to_many(model, old_field, new_field, strict)
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 785, in _alter_many_to_many
old_field.rel.through._meta.get_field(old_field.m2m_field_name()),
File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/django/db/models/options.py", line 554, in get_field
raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, field_name))
django.core.exceptions.FieldDoesNotExist: Account_following has no field named None
These are the model and the migrations:
models.py
from django.db import models
from django.contrib.auth.models import User
# Account
class Account(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
birth = models.DateField(blank=True, null=True)
text = models.TextField(blank=True)
avatar = models.URLField(blank=True)
following = models.ManyToManyField("self", symmetrical=False, related_name="followers", blank=True)
def __unicode__(self):
return unicode(self.user.username)
0001_initial.py (OK)
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations, models
from django.conf import settings
class Migration(migrations.Migration):
dependencies = [
migrations.swappable_dependency(settings.AUTH_USER_MODEL),
]
operations = [
migrations.CreateModel(
name='Account',
fields=[
('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
('birth', models.DateField(blank=True)),
('text', models.TextField(blank=True)),
('avatar', models.URLField(blank=True)),
('user', models.OneToOneField(to=settings.AUTH_USER_MODEL)),
],
),
]
0002_auto_20161116_1512.py (OK)
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations, models
class Migration(migrations.Migration):
dependencies = [
('main', '0001_initial'),
]
operations = [
migrations.AlterField(
model_name='account',
name='birth',
field=models.DateField(null=True, blank=True),
),
]
0003_account_following.py (OK)
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations, models
class Migration(migrations.Migration):
dependencies = [
('main', '0002_auto_20161116_1512'),
]
operations = [
migrations.AddField(
model_name='account',
name='following',
field=models.ManyToManyField(related_name='_account_following_+', to='main.Account', blank=True),
),
]
0004_auto_20170119_1151.py (fails)
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations, models
class Migration(migrations.Migration):
dependencies = [
('main', '0003_account_following'),
]
operations = [
migrations.AlterField(
model_name='account',
name='following',
field=models.ManyToManyField(related_name='followers', to='main.Account', blank=True),
),
]
I further provide my file .travis.yml:
language: python
python:
- "2.7"
env:
- DJANGO_VERSION=1.8
services:
- postgresql
addons:
postgresql: "9.3"
install:
- pip install -q Django==$DJANGO_VERSION
- pip install psycopg2
before_script:
- psql -c "CREATE USER enthub WITH PASSWORD 'enthub';" -U postgres
- psql -c "ALTER USER enthub CREATEDB;" -U postgres
script:
- python EntHub/manage.py test --verbosity=2
enthub/enthub are the credentials of database in settings.py.
Thanks in advance.

Answer 1

The problem seems to be a Django issue related to alter field migrations of many to many self-realted fields, but it's strange that it only appears on Travis. In the end, because the project is still under development, I have decided to delete the migrations 0003_account_following.py and 0004_auto_20170119_1151.py and run again the command python manage.py makemigrations. Now all works fine, but I have had to reset the database.