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Changes between Version 3 and Version 4 of Ticket #23408, comment 6

v3	v4
60	60	If default is set to a callable, I believe that it is implied that the result should be dynamically generated in Python/Django. If the functionality is to stay as stated in the result of this ticket, I would have to hand-code this migration for each app that previously existed to first create a nullable UUIDField with no default, then create a data migration to add distinct UUIDs to the Company, then write a migrations.AlterField migration to set null=False. The alternative might be to consider creating a special case for the UUIDField to allow for non-duplicated UUIDs to be created during migrations.
61	61
62		In the end, what the current resolution states is that we would have to hand-code the following migration to avoid the failure, which I feel violates the DRY principle, as that is why we allow for abstract models:
	62	From what I can take away, it has been stated that you cannot add/alter a field with null=False, unique=True without writing a custom migration. I would be much easier for if migrations followed the same standards as the [https://github.com/django/django/blob/1.7.1/django/db/models/fields/__init__.py#L713 django.db.models.fields.Field.get_default()] method. Currently, we have to hand-code the following migration to avoid the failure for every app which utilizes the AbstractUUIDModel, which I feel violates the DRY principle:
63	63	{{{
64	64	# -- coding: utf-8 --