Django循环依赖

Question

在应用迁移时，我得到了错误django.db.migrations.graph.CircularDependencyError。值得注意的是，我从一个空数据库开始。

我还设法归结为导致错误的类，它似乎是OAuthAccessToken。

class OAuthAccessToken(Model):

    user = models.OneToOneField(settings.AUTH_USER_MODEL, related_name='oauth_access_tokens',
        help_text=_('User'))

    provider = models.ForeignKey(Provider, related_name='oauth_access_tokens',
        help_text=_('OAuth provider'))

    token = fields.SafeRandomField(max_length=32,
        help_text=_('Access token'))

只有当我注释provider声明时，上面的代码才有效。Provider类来自allaccess框架。这是它的声明：

@python_2_unicode_compatible
class Provider(models.Model):
    "Configuration for OAuth provider."

    name = models.CharField(max_length=50, unique=True)
    request_token_url = models.CharField(blank=True, max_length=255)
    authorization_url = models.CharField(max_length=255)
    access_token_url = models.CharField(max_length=255)
    profile_url = models.CharField(max_length=255)
    consumer_key = EncryptedField(blank=True, null=True, default=None)
    consumer_secret = EncryptedField(blank=True, null=True, default=None)

使代码工作的另一种方法是从设置文件中删除AUTH_USER_MODEL = 'api.User'，在这种情况下，第一个代码示例可以工作。

问题是，我检查了这些迁徙，发现：

    migrations.CreateModel(
        name='OAuthAccessToken',
        fields=[
            ('uid', rest.fields.IDField(default=rest.fields.GenerateID(15, b'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'), max_length=15, serialize=False, primary_key=True, help_text='Server generated public unique ID')),
            ('creation_date', models.DateTimeField(help_text='Creation date', auto_now_add=True)),
            ('last_update', models.DateTimeField(help_text='Last update', auto_now=True)),
            ('token', rest.fields.SafeRandomField(default=rest.fields.GenerateID(32, b'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'), help_text='Access token', max_length=32)),
            ('provider', models.ForeignKey(related_name='oauth_access_tokens', to='allaccess.Provider', help_text='OAuth provider')),
            ('user', models.OneToOneField(related_name='oauth_access_tokens', to=settings.AUTH_USER_MODEL, help_text='User')),
        ],
        options={
            'abstract': False,
        },
        bases=(models.Model,),
    ),

但我看不出循环依赖在哪里。

编辑：

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/Library/Python/2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/Library/Python/2.7/site-packages/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Library/Python/2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/Library/Python/2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/Library/Python/2.7/site-packages/django/core/management/commands/migrate.py", line 106, in handle
    plan = executor.migration_plan(targets)
  File "/Library/Python/2.7/site-packages/django/db/migrations/executor.py", line 49, in migration_plan
    for migration in self.loader.graph.forwards_plan(target):
  File "/Library/Python/2.7/site-packages/django/db/migrations/graph.py", line 55, in forwards_plan
    return self.dfs(node, lambda x: self.dependencies.get(x, set()))
  File "/Library/Python/2.7/site-packages/django/db/migrations/graph.py", line 105, in dfs
    raise CircularDependencyError()
django.db.migrations.graph.CircularDependencyError

编辑:使用django 1.7.7更新

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/Library/Python/2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/Library/Python/2.7/site-packages/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Library/Python/2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/Library/Python/2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/Library/Python/2.7/site-packages/django/core/management/commands/migrate.py", line 106, in handle
    plan = executor.migration_plan(targets)
  File "/Library/Python/2.7/site-packages/django/db/migrations/executor.py", line 54, in migration_plan
    for migration in self.loader.graph.forwards_plan(target):
  File "/Library/Python/2.7/site-packages/django/db/migrations/graph.py", line 60, in forwards_plan
    return self.dfs(node, lambda x: self.dependencies.get(x, set()))
  File "/Library/Python/2.7/site-packages/django/db/migrations/graph.py", line 124, in dfs
    self.ensure_not_cyclic(start, get_children)
  File "/Library/Python/2.7/site-packages/django/db/migrations/graph.py", line 112, in ensure_not_cyclic
    raise CircularDependencyError(", ".join("%s.%s" % n for n in cycle))
django.db.migrations.graph.CircularDependencyError: api.0001_initial, allaccess.0001_initial

Answer 1

碰巧我需要重构代码并创建一个新的应用程序来包含一些模型来解决这个问题。Django然后创建几个迁移(比如0002,0003)，因此能够解决循环依赖。