But that's MO; please wait for Dmitry to chime in.
[ Sorry for the late response, I'm still uncertain about this patch. ]
(*) ... and ask whether this functionality makes sense built-in.
I appreciate that it's succinct, documented and doesn't take a lot of
space. But would we say that it covers a significantly general use
case? Do we know many other developers who would appreciate it? Do a
lot of devs at Jane Street use Emacs and this same workflow? Should we
ask people somewhere (emacs-devel/Reddit/etc) whether they will find
it useful?
It's something we'd use a lot, but I have no problem keeping it locally
for now. I agree it has some dangers, maybe I'll come up with a good
way to make it safe for the casual user.
If it's just for one user at this point, then it shouldn't be
difficult to maintain this code inside the init dir.
Here's also some alternative I could potentially suggest: if you have
some code which checks out new branches for development, or projects
to start work on, and it's written in Elisp too, could it just call
project-remember-project at the end? That would circumvent the need
for using file watches altogether.
That works great for stuff written in Elisp too, but alas, there are
command line tools to check out branches for development, etc, and I
want them to update Emacs too.