Django 为什么prefetch_related（）会引发AttributeError？

我有一个与第二个模型有多对多关系的模型。当我尝试使用预回迁时，我会得到一个AttributeError。这些模型可概括为：

class AcademicSubject(TranslatableModel):
    translations = TranslatedFields(
        name = CharField(max_length=255)
    )

class UserProfile(Model):
    user = OneToOneField(settings.AUTH_USER_MODEL)
    # ... other fields
    subjects = ManyToManyField(AcademicSubject, blank=True)

（省略了各种细节）。

translateablemodel

和

translateedfields

都是源代码，虽然我不认为它们在这种情况下很重要，但我不是100%确定，所以我想我应该包括它们

我尝试迭代的查询集是：

UserProfile.objects.all().select_related('user').prefetch_related('subjects')

我得到的stacktrace是：

Traceback:
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  111.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  105.                     response = view_func(request, *args, **kwargs)
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
  52.         response = view_func(request, *args, **kwargs)
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner
  206.             return view(request, *args, **kwargs)
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/views/generic/base.py" in view
  69.             return self.dispatch(request, *args, **kwargs)
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/views/generic/base.py" in dispatch
  87.         return handler(request, *args, **kwargs)
File "/home/hamish/dev/django/website/mentor_reports/views.py" in get
  45.         for item in self.get_queryset():
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/db/models/query.py" in __iter__
  141.         self._fetch_all()
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/db/models/query.py" in _fetch_all
  968.             self._prefetch_related_objects()
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/db/models/query.py" in _prefetch_related_objects
  611.         prefetch_related_objects(self._result_cache, self._prefetch_related_lookups)
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/db/models/query.py" in prefetch_related_objects
  1791.                 obj_list, additional_lookups = prefetch_one_level(obj_list, prefetcher, lookup, level)
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/db/models/query.py" in prefetch_one_level
  1906.         rel_attr_val = rel_obj_attr(rel_obj)
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/db/models/fields/related.py" in <lambda>
  912.                     lambda result: tuple(getattr(result, '_prefetch_related_val_%s' % f.attname) for f in fk.local_related_fields),
File "/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/db/models/fields/related.py" in <genexpr>
  912.                     lambda result: tuple(getattr(result, '_prefetch_related_val_%s' % f.attname) for f in fk.local_related_fields),

Exception Type: AttributeError at /en/admin/user_report
Exception Value: 'AcademicSubject' object has no attribute '_prefetch_related_val_userprofile_id'

回溯：
get_响应中的文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/core/handlers/base.py”
111响应=包装的回调（请求，*回调参数，**回调参数）
视图中的文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/utils/decorators.py”
105响应=查看功能（请求，*args，**kwargs）
文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site-packages/django/views/decorators/cache.py”位于
52响应=查看功能（请求，*args，**kwargs）
文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/contrib/admin/sites.py”，位于内部
206返回视图（请求、*args、**kwargs）
视图中的文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/views/generic/base.py”
69返回自调度（请求，*args，**kwargs）
文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/views/generic/base.py”在dispatch中
87返回处理程序（请求、*args、**kwargs）
get中的文件“/home/hamish/dev/django/website/mentor_reports/views.py”
45对于self.get_queryset（）中的项：
文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/db/models/query.py”位于__
141self._fetch_all（）
文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/db/models/query.py”位于
968self.\u预取\u相关\u对象（）
文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/db/models/query.py”位于预回迁相关对象中
611预取\相关\对象（自。\结果\缓存、自。\预取\相关\查找）
预回迁相关对象中的文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/db/models/query.py”
1791obj_列表，附加_查找=预取_一级（obj_列表，预取器，查找，级别）
预回迁级别的文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/db/models/query.py”
1906rel_attr_val=rel_obj_attr（rel_obj）
文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/db/models/fields/related.py”
912lambda result:tuple（fk.local\u related\u字段中f的getattr（结果，'.\u预取\u related\u val\u%s'%f.attname）），
文件“/home/hamish/dev/django/website/.ve/local/lib/python2.7/site packages/django/db/models/fields/related.py”
912lambda result:tuple（fk.local\u related\u字段中f的getattr（结果，'.\u预取\u related\u val\u%s'%f.attname）），
异常类型：AttributeError at/en/admin/user\u报告
异常值：“AcademicSubject”对象没有属性“\u prefetch\u related\u val\u userprofile\u id”

我正在使用Django 1.7

---

我的设置中有什么地方看起来不正确吗？

在

类UserProfile（Model）

之后缺少一个冒号，但我可以反复使用该查询设置。你能发布一些其他细节吗？