Alphabet must contain at least 16 unique characters

[wowkin2]

In fresh version 3.1.2 something was changed and crashes usage of Django url reversion ({% url 'blog_post' post_id=post.id %}). Version 3.1.1 works fine.
I have custom alphabet for HashidAutoField:
id = HashidAutoField(primary_key=True, alphabet=HASHID_ALPHABET, min_length=HASHID_MIN_LENGTH)

[nshafer]

This is nothing new, and it's a requirement of the Hashids library and the algorithm. If you're not providing 16 unique charactes, then I have no idea how it was working before. The only thing that's different is that in 3.1.2 an instance of the Hashids library is created on startup, whereas before it was created on-the-fly. But there was a check for the length, so did you have checks disabled or something? What is the value of HASHID_ALPHABET?

[nshafer]

I just published 3.1.3 that properly checks that the given alphabet has at least 16 unique characters... it was only checking overall length and would let through 16 duplicates. I would still like to know what your HASHID_ALPHABET is set to.