Comments without any fields are still possible to add

[nickonom]

Description of the bug

It's not a bug per se, but a nuance that fails foolproof test. To replicate it, just delete all comment fields, go to the content's page and you can still see the comment form without any fields and you can actually submit it.

[indigoxela]

Comments without any fields... that's an edge case (site builder / admin didn't think 😉 ).

I wonder, where / how we could catch that. And actually: should we catch that? There are for sure several situations where admins can do something not-so-smart...

[nickonom]

Not sure if it should be dealt with at all, however shouldn't eventually Backdrop CMS' core be stripped of all to-avoid nuances like that? I think the comment form should not be offered to user if there are no any comment fields.