Proper (hopefully) fix for…

Proper (hopefully) fix for https://github.com/alex/django-taggit/commit/20a8063c4deb8fb3c5440787cd8114cb2fdf8537#commitcomment-4715554

taggit/managers.py

@@ -96,6 +96,7 @@ class TaggableManager(RelatedField, Field):
         else:
             self.set_attributes_from_name(name)
         self.model = cls
+
         cls._meta.add_field(self)
         setattr(cls, name, self)
         if not cls._meta.abstract:
@@ -109,6 +110,7 @@ class TaggableManager(RelatedField, Field):
             else:
                 self.post_through_setup(cls)
 
+
     def __lt__(self, other):
         """
         Required contribute_to_class as Django uses bisect
@@ -125,11 +127,14 @@ class TaggableManager(RelatedField, Field):
         self.rel.to = self.through._meta.get_field("tag").rel.to
         self.related = RelatedObject(self.through, cls, self)
         if self.use_gfk:
-            self.__class__._related_name_counter += 1
-            related_name = '+%d' % self.__class__._related_name_counter
-            tagged_items = GenericRelation(self.through, related_name=related_name)
+            tagged_items = GenericRelation(self.through)
             tagged_items.contribute_to_class(cls, 'tagged_items')
 
+            for rel in cls._meta.local_many_to_many:
+                if isinstance(rel, TaggableManager) and rel.use_gfk and rel != self:
+                    raise ValueError('You can only have one TaggableManager per model'
+                        ' using generic relations.')
+
     def save_form_data(self, instance, value):
         getattr(instance, self.name).set(*value)
 
@@ -291,7 +296,7 @@ class _TaggableManager(models.Manager):
     def get_prefetch_query_set(self, instances, queryset = None):
         if queryset is not None:
             raise ValueError("Custom queryset can't be used for this lookup.")
-        
+
         instance = instances[0]
         from django.db import connections
         db = self._db or router.db_for_read(instance.__class__, instance=instance)

tests/models.py

@@ -8,9 +8,18 @@ from taggit.models import (TaggedItemBase, GenericTaggedItemBase, TaggedItem,
     TagBase, Tag)
 
 
+# Ensure that two TaggableManagers with custom through model are allowed.
+class Through1(TaggedItemBase):
+    content_object = models.ForeignKey('MultipleTags')
+
+
+class Through2(TaggedItemBase):
+    content_object = models.ForeignKey('MultipleTags')
+
+
 class MultipleTags(models.Model):
-    tags1 = TaggableManager()
-    tags2 = TaggableManager(related_name='+')
+    tags1 = TaggableManager(through=Through1, related_name='tags1')
+    tags2 = TaggableManager(through=Through2, related_name='tags2')
 
 
 @python_2_unicode_compatible
@@ -50,7 +59,7 @@ class TaggedPet(TaggedItemBase):
 class DirectFood(models.Model):
     name = models.CharField(max_length=50)
 
-    tags = TaggableManager(through="TaggedFood")
+    tags = TaggableManager(through='TaggedFood')
 
     def __str__(self):
         return self.name