  
  
  class Tag(models.Model):
      name = models.CharField(max_length=30)
      content_type = models.ForeignKey(ContentType, related_name='backend_tags')
      object_id = models.PositiveIntegerField()
      content_object = GenericForeignKey('content_type', 'object_id')
  
  
  class Post(models.Model):
 
</s> remove     content_type = models.ForeignKey(ContentType)
 </s> add     content_type = models.ForeignKey(ContentType, models.CASCADE) </s> remove     content_type = models.ForeignKey(ContentType)
 </s> add     content_type = models.ForeignKey(ContentType, models.CASCADE) </s> remove     content_type = models.ForeignKey(ContentType)
 </s> add     content_type = models.ForeignKey(ContentType, models.CASCADE) </s> remove     content_type = models.ForeignKey(ContentType, related_name='tagged_items')
 </s> add     content_type = models.ForeignKey(ContentType, models.CASCADE, related_name='tagged_items') </s> remove     content_type = models.ForeignKey(ContentType)
 </s> add     content_type = models.ForeignKey(ContentType, models.CASCADE)
    content_type = models.ForeignKey(ContentType, models.CASCADE, related_name='backend_tags')
  
  
  class Tag(models.Model):
      name = models.CharField(max_length=30)
    content_type = models.ForeignKey(ContentType, models.CASCADE, related_name='backend_tags')
      object_id = models.PositiveIntegerField()
      content_object = GenericForeignKey('content_type', 'object_id')
  
  
  class Post(models.Model):
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/backends/models.py