Fix Conflicting migrations detected in Django1.9

问题

I updated django-dynamic-model repository to support Django 1.9. I got this error:

CommandError: 

Conflicting migrations detected; multiple leaf nodes in the migration
graph: (0001_initial, 0002_auto__add_field_dynamicschemafield_extra in
dynamicmodel).
To fix them run 'python manage.py makemigrations --merge'

After running python manage.py makemigrations --merge, I got another error:

 File "/local/lib/python2.7/sitepackages/django/core/management/__init__.py",  
line 353, in execute_from_command_line
utility.execute()

 File "/local/lib/python2.7/sitepackages/django/core/management/__init__.py", line 345, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)

 File 
"/local/lib/python2.7/site-packages/django/core/management/base.py", line 348, in run_from_argv
self.execute(*args, **cmd_options)

File 
"/local/lib/python2.7/site-packages/django/core/management/base.py", line 399, in execute
output = self.handle(*args, **options)

File 
"/local/lib/python2.7/site-packages/django/core/management/commands/makemigrations.py", line 97, in handle
return self.handle_merge(loader, conflicts)

File 
   "/local/lib/python2.7/site-packages/django/core/management/commands/makemigrations.py", line 216, in handle_merge
 raise ValueError("Could not find common ancestor of %s" % migration_names)


 ValueError: Could not find common ancestor of set([u'0001_initial', u'0002_auto__add_field_dynamicschemafield_extra']). 

Help me to find the solution.

回答1:

The migrations need to have "straight" dependency chain, i.e. migration 0003 needs to depend on migration 0002, and 0002 on 0001.

You need to define this in the 0003_third.py like this:

class Migration(migrations.Migration):
    dependencies = [
        ('modulename', '0002_second'),
    ]

回答2:

Seems like you have injected models of other applications.

Define TARGET_APP in your migrations, seems like migrations loader can't correctly identify target app.

来源：https://stackoverflow.com/questions/36656495/fix-conflicting-migrations-detected-in-django1-9