"+file?+ is not a valid predicate name"

Should the example here ‘just work’?

I’m seeing the above error when trying to validate a file upload.

Is file? a formerly supported predicate?

I guess I could just validate its type, but thought the linked example looked more specific (image type and size).


Edit: To validate its type, I tried .maybe(type?: ActionDispatch::Http::UploadedFile), but received the error:

Nothing registered with the key "action_dispatch.http.uploaded_file"

Which I gather is a known issue:

Not doing too well with this so far. :frowning:

Any ideas how to validate a file upload using dry-validation within Rails? (Searching hasn’t turned up much.)