bug#65120: 29.1; directory-abbrev-alist breaks various things when inside an abbreviated directory

[Eli Zaretskii]

> From: Sean Allred <allred.sean@gmail.com>
> Cc: Sean Allred <allred.sean@gmail.com>, 65120@debbugs.gnu.org
> Date: Wed, 09 Aug 2023 06:28:55 -0500
> 
> So, I'd like to shorten this $MegaCorpSource path using built-in
> functionality where possible. My users aren't going to care about most
> of the path components. I can roll my own, but is there something like
> `abbreviate-file-name' that doesn't assume we're working with symlinks?
> (Should/could there be? Thoughts on whether or not it is A Good
> Idea(tm)?)

I don't think there's something in Emacs.  But you can use
directory-abbrev-alist if you define a drive (using 'subst') that
would remove the need for using the full file name.  Something like

  subst x: C:\$MegaCorpSource

Then you could use "x:/" in directory-abbrev-alist.  This actually
matches the "symlink" idea of this feature on Unix.

(Yes, I know: corporate IT doesn't like SUBST very much, either.  But
maybe you will be lucky...)