修复 Django1.9 中检测到的冲突迁移

Question

我更新了django-dynamic-model 存储库以支持 Django 1.9。我收到了这个错误：

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'

运行python manage.py makemigrations --merge后，又报错：

 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']). 

帮我找到解决办法。

Answer 1

好像您注入了其他应用程序的模型。

在您的迁移中定义 TARGET_APP，似乎迁移加载器无法正确识别目标应用。

Answer 2

迁移需要有“直接”的依赖链，即迁移 0003 需要依赖于迁移 0002，而 0002 需要依赖于 0001。

您需要像这样在 0003_third.py 中定义它：

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