Re: [Emacs-diffs] master 0528a7c: Ensure that expand-file-name returns an absolute file name

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: kbrown@cornell.edu,  emacs-devel@gnu.org
> Date: Tue, 09 Jul 2019 11:25:50 -0400
> 
> > It isn't entirely arbitrary.
> 
> I'd have gone with "/", but I also consider that as arbitrary: I don't
> think there can be a non-arbitrary choice here, other than signaling
> an error because we don't have any information that can give us a hint
> about what was the intended absolute directory.

I see nothing wrong with a somewhat arbitrary interpretation of such a
default-directory value.

> > I think expand-file-name should try to avoid signaling an error as
> > much as possible, because it is called by many primitives and core
> > functions.  If we signal an error, we risk getting the users into a
> > situation where they cannot even shut down Emacs, let alone do
> > something less trivial.
> 
> A relative default-directory is something extremely rare, so if some
> operations like C-x C-c fail in that case I wouldn't mind.

I agree that it is rare, but trapping the user even rarely is
something I'd like to avoid as much as reasonably possible.