Rails Sanitize Gem: Frozen Allowed Tags List is Mutated Internally #195
Description
We have observed a problematic behavior in the latest version of the sanitize gem when using a frozen list for allowed_tags. Specifically, the gem mutates the provided frozen list internally, which leads to a RuntimeError (can't modify frozen Array) or unexpected behavior.
This mutation is unexpected because frozen objects are intended to remain immutable, and the gem should ideally create a copy of the provided list if internal modifications are required.
So, to avoid this problem we had to use .dup to create a shallow copy, which should be happening internally.