Not possible to seed uuid4

It is not possible to seed the uuid4 property.

>>> f1 = Faker()
>>> f1.seed(4321)
>>> print(f1.uuid4())
4a6d35db-b61b-49ed-a225-e16bc164f7cc

>>> f2 = Faker()
>>> f2.seed(4321)
>>> print(f2.uuid4())
b5f05be8-2f57-4a52-9b6f-5bcd03125278

The solution is pretty much given in: http://stackoverflow.com/questions/41186818/how-to-generate-a-random-uuid-which-is-reproducible-with-a-seed-in-python

[kevin-brown]

The tests which were added in #1050 (and closed out this ticket) are still in the repo at

https://github.com/joke2k/faker/blob/594d34414b137071f59b9fc75442206244c234cd/tests/providers/test_misc.py#L68-L75

I don’t use Faker anymore, but after looking at the code it looks like it should now work with seeding and properly return v4 UUIDs.

[kevin-brown]

Is it correct that you can’t see a difference between an (incorrect) UUID4 in Faker and a valid UUID4?

That is not correct. And 15/16 times it will produce a UUID that is not version 4.

>>> u = uuid.UUID(int=random.getrandbits(128))
>>> u
UUID('7119ccd3-e9be-c160-8d0d-608e5f5ea285')
>>> u.version
12

There are a total of 8 bits that must be set manually in order for it to be properly detected as a UUIDv4.

>>> uuid.UUID(int=(random.getrandbits(128) | (1<<63) | (1<<78)) & (~(1<<79) & ~(1<<77) & ~(1<<76) & ~(1<<62))).version
4
>>> uuid.UUID(int=(random.getrandbits(128) | (1<<63) | (1<<78)) & (~(1<<79) & ~(1<<77) & ~(1<<76) & ~(1<<62))).version
4
>>> uuid.UUID(int=(random.getrandbits(128) | (1<<63) | (1<<78)) & (~(1<<79) & ~(1<<77) & ~(1<<76) & ~(1<<62))).version
4
>>> uuid.UUID(int=(random.getrandbits(128) | (1<<63) | (1<<78)) & (~(1<<79) & ~(1<<77) & ~(1<<76) & ~(1<<62))).version
4
>>> uuid.UUID(int=(random.getrandbits(128) | (1<<63) | (1<<78)) & (~(1<<79) & ~(1<<77) & ~(1<<76) & ~(1<<62))).version
4