I have git repo here: ~/git/myrepo/
then I do:
ln -s ~/external_dir ~/git/myrepo emacs follows symbolic link when opening the file: ~/git/myrepo/external_dir/somefile.txt
I'd like to prevent it, ideally on a per git repo (dir-locals) basis
following doesn't bring the desired effect:
(setq vc-follow-symlinks nil) also:
(setq vc-follow-symlinks 'ask) does not make emacs ask a question when opening a file.
I'm running emacs.28.2
please help
I think you misunderstood the purpose of vc-follow-symlinks.
In the situation you described, Emacs doesn't ask anything because the version controlled file ~/git/myrepo/external_dir, which is a symbolic link, is not edited. The file that is edited is ~/external_dir/somefile.txt and is not under version control as long as ~/external_dir is not a Git repository.
By setting vc-follow-symlinks to 'ask, Emacs will prompt you if the target of a symbolic link is under version control.
Example :
ln -s ~/git/myrepo/someotherfile.txt ~/external_dir/someotherlink ~/git/myrepo/someotherfile.txt, the target of the symbolic link ~/external_dir/someotherlink is under version control. Now if you invoke e.g. find-file ~/external_dir/someotherlink, Emacs will prompt you (still assuming vc-follow-symlinks is set to 'ask).
cd ~/git/myrepo/external_dir, then pwd tells it's in /home/user/git/myrepo/external_dir. I'd like emacs behave the same way. ~/git/myrepo/external_dir you will end up in a Dired buffer where the directory name is /home/user/git/myrepo/external_dir. Emacs does behave the same way as the shell. At the end, I don't know how to prevent Emacs from resolving the symbolic link in your situation.