Klever

Indeed this looks more like a bug. Related issue #8118 wasn't formulated accurately enough. That's why now various operations with tags are complicated. The new suggested model looks to be very generic and will bring us all the necessary capabilities.

Implemented in feature_8292.

I caught the following exception:

get() returned more than one UnsafeTagAccess -- it returned 2!
Traceback (most recent call last):
  File "/home/novikov/work/klever/bridge/marks/views.py", line 536, in show_tags
    tags_data = GetTagsData(tags_type, user=request.user)
  File "/home/novikov/work/klever/bridge/marks/tags.py", line 151, in __init__
    self.__get_tags()
  File "/home/novikov/work/klever/bridge/marks/tags.py", line 168, in __get_tags
    [TagData(self.user, tag) for tag in UnsafeTag.objects.filter(**tags_filter).order_by('tag')]
  File "/home/novikov/work/klever/bridge/marks/tags.py", line 168, in <listcomp>
    [TagData(self.user, tag) for tag in UnsafeTag.objects.filter(**tags_filter).order_by('tag')]
  File "/home/novikov/work/klever/bridge/marks/tags.py", line 135, in __init__
    self.can_edit = self._access.edit()
  File "/home/novikov/work/klever/bridge/marks/tags.py", line 60, in edit
    return self._is_manager or self.__has_edit_access()
  File "/home/novikov/work/klever/bridge/marks/tags.py", line 43, in __has_edit_access
    return access_table.objects.get(user=self.user, tag=self.tag).modification
  File "/home/novikov/.pyenv/versions/virtual-env-3.6.1/lib/python3.6/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/novikov/.pyenv/versions/virtual-env-3.6.1/lib/python3.6/site-packages/django/db/models/query.py", line 383, in get
    (self.model._meta.object_name, num)
marks.models.MultipleObjectsReturned: get() returned more than one UnsafeTagAccess -- it returned 2!

I hope that now it works like the most of us agrees with. I merged the branch to master in 3d010b9e.