I tend to stash changes without remembering why I stash them.
I do make it a point to git stash push -m most of the time, but if there's a fire drill or something else that knocks me out of flow, I may forget and lose time trying to recover.
Is there a way to imitate the behavior of git commit (minus the -m) for git stash where vim pops up and abandons the operation if the message is empty?
AFAIK there's no config option for this. You'll have to write an alias in your .gitconfig and train yourself to use it.
For example, I have two stash aliases git pop and git save. (You can see I didn't get the memo about git stash save being deprecated). These are both for convenience, and to change the default behavior to something I find more useful.
save = stash save -k -u
pop = stash pop
Unfortunately git stash push -m doesn't bring up an editor, if you need to write more than a few words to describe what you were doing consider a branch instead. We can fix this by writing a little shell function and passing the argument to -m using "$@" to ensure messages with spaces are a single argument.
savem = "!f() { git save -m \"$@\"; }; f"
Now you can write git savem 'remember to remember what this was'.
$ git savem 'remember to remember what this was'
Saved working directory and index state On issue/45: remember to remember what this was
And if you forget, you'll get the normal git-stash usage message. You can snazz up the alias to provide a custom usage message if you like.
$ git savem
usage: git stash list [<options>]
or: git stash show [<stash>]
...