I\'m having a helluva time getting git to cooperate with my user-defined worktree that exists outside the folder that contains my .git directory.
Ba
git --git-dir= --work-tree= stash
should work. Have you tried absolute paths?
UPDATE:
seems to be a bug. The extended functionality of --git-dir option was only added recently and some commands like git stash don't have the new implementation yet.
git-stash is a bash script. You could hack it and remove the require working dir check then cd into the working folder.