Task description update
@DLynch raised some questions we ought to consider before implementing this change. David, can you please post the "behavioral matrix" you shared in chat as a comment on this task?

This represents the current behavior of the tool:

"Blank summary" means literally an empty input. "Default summary" means whatever we auto-generate for you.

(You could argue that it could contain more state inputs, like whether the field had been changed in the current session or before a state-restore on a page reload. But that's not currently a factor that's considered.)

Oh, that matrix is very-specifically focused on the behavior when you actually submit the reply. There's additional what-happens to consider if reloading the page and restoring state is added to the mix.

When would a user ever encounter a blank text summary field? Is it just the moment that they click into it? Or is it if there is a blank comment and then the user clicks advanced?

@iamjessklein I was assuming it was the case where they'd manually deleted the content of the field.

Task description update
I've added "USE CASE 2" to the task description's ===Behavior section.

Change 628178 had a related patch set uploaded (by Esanders; owner: Esanders):
[mediawiki/extensions/DiscussionTools@master] Always send edit summary, regardless of visibility

https://gerrit.wikimedia.org/r/628178

Change 628178 merged by jenkins-bot:
[mediawiki/extensions/DiscussionTools@master] Always send edit summary, regardless of visibility

https://gerrit.wikimedia.org/r/628178