bug#13930: Emacs doesn't cope well if it can't access/create .emacs.d

[Eli Zaretskii <eliz@gnu.org>]

> From: Glenn Morris <rgm@gnu.org>
> Cc: Robert Prije <rprije@janestreet.com>,  13930@debbugs.gnu.org
> Date: Tue, 12 Mar 2013 12:29:23 -0400
> 
> Eli Zaretskii wrote:
> 
> >> It does exactly the same thing with --debug-init (says "creating directory:
> >> permission denied...") and supplies no further information.
> >
> > How about running it under GDB with a breakpoint on report_file_error
> > and on xsignal?  If you start GDB from the src directory of the Emacs
> > sources, the .gdbinit file there defines a command xbacktrace which
> > will produce a Lisp-level backtrace in addition to the C-level
> > backtrace produced by the "bt" command of GDB.
> 
> Why do we need to jump through such hoops, when locate-user-emacs-file,
> which Stefan has just added all over the place, says:
> 
>   Else return NEW-NAME in `user-emacs-directory', creating the
>   directory if it does not exist.

If you mean that remembering this was all you needed to deduce that
locate-user-emacs-file is the culprit, then good for you.  I never
remember such details (and this one I think I never knew about in the
first place).  A debugger will show the truth even if the problem is
in some other place, so it is (IMO) a more efficient way of finding
the root cause.

IOW, more often than not I find that "jumping through hoops" is the
shortest and most reliable way to solution.