Array type "empty_values" cannot remove all empty values

Honestly, that was added so long ago its hard to say what the original rationale was

1. Ash strings (by default), cast to nil.
2. We have the nil_items? constraint, which rejects nil values. For us empty_values is a separate kind of thing, representing when the entire list is empty.
3. I think what you want is a new constraint, called remove_nil_items? that will remove nil items instead of making them an error if they exist.

Adding a remove_nil_items? constraint should be pretty straightforward.

But now that you mention it, it’s also unexcepted behavior that nil values make it through to the database if they are initially empty strings.

To circumvent that issue, I guess the is_nil check would benefit from being rerun after applying the item’s type constraints here:

https://github.com/ash-project/ash/blob/v2.21.14/lib/ash/type/type.ex#L704-L713

But that would probably be considered a breaking change, right?

Maybe we should continue that discussion in a GitHub issue or draft PR, let me know!

I would say that we should move the is_nil check to after applying constraints to the inner items, primarily because types could even theoretically do the reverse, taking a nil item and casting it to a value.

I also wouldn’t personally consider it a breaking change, but rather a bug fix. If nil_items?: false can still produce an array with nil items, that counts as a bug in my book

Please open an issue for these so we can make sure to address them (or of course a PR )

GitHub links for posterity:

• fix: run array type nil check after item constraints by sheerlox · Pull Request #1115 · ash-project/ash · GitHub
• feat: add new remove_nil_items? array type constraint by sheerlox · Pull Request #1116 · ash-project/ash · GitHub