Seems like this is working as it is supposed to.

This is expected behaviour.

rschnautz wrote:

Except I've been able to reproduce it consistently. Something's definitely wrong here.

Expected behavior? Either you allow it and don't show it's not allowed, or you don't allow it and actually prevent it. Doing a combination of both seems unreasonable to me...

(In reply to comment #3)

Except I've been able to reproduce it consistently. Something's definitely
wrong here.

What do you think should happen?

rschnautz wrote:

Mark, it seems straightforward to me:

If a user is told they're unable to blank, they shouldn't be able to blank. The edit shouldn't commit, and the edit dialog should remain open instead.

(In reply to comment #6)

If a user is told they're unable to blank, they shouldn't be able to blank.

Deletion is different than blanking.

It took some time, but I was able to delete a post by blanking it. Usually, even with funny Unicode characters like "em-space", I got a notice saying that I couldn't create an empty title or any empty post.

Now that I have been able to sporadically duplicate what you saw, I'm giving this to Chris McMahon to see if he can get a better reproduction.

(In reply to comment #7)

Now that I have been able to sporadically duplicate what you saw, I'm giving
this to Chris McMahon to see if he can get a better reproduction.

I tested this here:
https://www.mediawiki.org/wiki/User:MarkAHershberger/lqt-test

There is only one topic open with the subject removed by my test user ("Hexmode"). There was another topic open which my test user was (after a bit of trying) able to remove.

Valerie.m.juarez wrote:

Can confirm.

I was able to delete the thread 'Starting a new discussion?' by blanking out the body and title. I got a message "You cannot post a blank message" but it went through anyway.

See history: https://test2.wikipedia.org/w/index.php?title=Talk:Xpd&lqt_method=talkpage_history
The last Activity in thread 'Starting a new discussion?' is 'Removed comment text'. This is where I blanked out the message.

And current talk page: https://test2.wikipedia.org/wiki/Talk:Xpd has no thread called 'Starting a new discussion?'.