This is a fantastic mention! I've been commenting out my commit message lines and then saving as a way to trigger this. Feeling like a caveman...

Guilty as changed your honour

Guilty as UNchanged*

I just love nuggets like this. I've been using VIM for 26 years and git for about 15. I never knew about adding c. I've always felt that :q! should exit with a non-zero status code, at least if no :w had been made.

I usually use :q! which seems to do the same thing

The minor difference is that :q! quits without saving but returns zero as the exit code, but :cq quits with a nonzero exit code. Git interprets the nonzero exit code as "editing failed", following the Unix convention that zero means success. If you didn't save the commit message while working on it, :q! will send the empty template back to Git, which Git is smart enough to not commit. But if you accidentally save your work partway through, :q! will still commit the message you wanted to abandon.

That only works if the edit buffer is blank or only has commented out lines. In other cases, such as when you're trying to cancel a `git commit --amend` that loads up the last commit message in your buffer, :q! will not cancel the commit, but :cq will.

TIL! The funny thing about Vim is that you can have used vi/Vim for 30+ years and still learn new things. I'll add this to the Vim appendix. Cheers!

It is the same with Git

If you have been using git for 30+ years, you need to take me to your time machine. It turns 20 this year.

Interesting I’ve always just deleted the contents of the entire buffer and :wq to cause a failure due to lack of message

Mnemonic to help remember: cancel quit

:cq is useful in a shell loop that compares two directory trees that invokes vim to let you see what's changed in every file that's different. I use it often:

    ((cd /tmp/t; find . -type f -print) | sort | while read f; do cmp -s {/tmp/t,/tmp/t1}/$f || vim -f -d {/tmp/t,/tmp/x1}/$f 0<&9 || break; done) 9<&0

Typing ^C to vim doesn't get you very far, so if you make a mistake causing the loop to return 1000's of files you are in for a bit of pain without :cq. The :cq triggers the break, exiting the loop.