bug#36490: 26.1; directory-files-recursively breaks when it encounters a directory named "~"

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: 36490@debbugs.gnu.org,  erik_hahn@gmx.de
> Date: Wed, 10 Jul 2019 13:55:33 +0200
> 
> >   (file-name-as-directory "~")
> >     => "~/"
> >
> > So just running "~" through an innocent API gives you a "magic"
> > directory name (if you consider "~" not "magic" by itself).  How is
> > this different from the "odd" use case where one must quote "~" to
> > avoid its interpretation as the home directory?  Who can guarantee
> > that some day directory-files-recursively will not want to do
> > something like the above?  If it does, we will be right back at the
> > same problem.
> 
> Well...  That kinda sounds odd to me.
> 
> "~/" is not, and never will be, a valid file name in any OS that Emacs
> is going to support from now on.

I don't think I follow you.  "~" is a perfectly valid name of a
directory, and Emacs does support such names in general.  So I don't
think I understand why you are saying this will not be a valid file
name.  What did I miss?

> But changing that is probably not going to happen, so how about just
> clarifying the documentation in that function to say what "~" means
> explicitly instead of the caller having to guess?

I don't object to documenting this.