bug#4902: 23.1; directory-abbrev-alist is not handled early enough

[Eli Zaretskii]

> Date: Tue, 10 Nov 2009 16:29:36 -0500
> From: "David J. Biesack" <David.Biesack@sas.com>
> Cc: 4902@emacsbugs.donarmstrong.com
> 
> Obviously, there are too many different names for the same file,
> and I want Emacs to normalize all files to a canonical
> form; i.e. all the variations of my network home should
> be normalized to u:/ and so forth.
> 
> directory-abbrev-alist:
> 
> '(("^//dntsrc/u/sasdjb" . "u:")
>   ("^/u/sasdjb" . "u:")
>   ("^//sashq/root/u/sasdjb" . "u:")
>   ("^/nfs/sanyo/vol/vol2/u22/sasdjb" . "u:/")
>   ("^//sashq/root/u/sasdjb" . "u:")
>   ("^/sas/" . "//dntsrc/sas/")
>   ("^/sasgen" . "//dntsrc/sasgen/"))
> 
> If I'm running Emacs on Linux, I would normalize all
> these variations the other way:
> 
> directory-abbrev-alist:
> 
> '(("^//dntsrc/u/sasdjb" . "/u/sasdjb")
>   ("^u:" . "/u/sasdjb")
>   ("^//sashq/root/u/sasdjb" . "/u/sasdjb")
>   ("^/nfs/sanyo/vol/vol2/u22/sasdjb" . "/u/sasdjb")
>   ("^//sashq/root/u/sasdjb" . "/u/sasdjb")
>   ("^//dntsrc/sas/" . "/sas/")
>   ("^//dntsrc/sasgen/" . "/sasgen"))

So you are trying to solve in Emacs a problem that is not for Emacs to
solve.  You are trying to emulate a symlink using Emacs features that
are not at all intended for such a use.

Personally, I don't think this problem even should be solved in
Emacs.  You still have other tools which need to see the correct file
name, so any mapping Emacs does internally will never be sufficient.

About the only thing I can suggest is to run with the drive u: being
the current drive.  Then /foo/bar on both Windows and Unix will refer
to the same place, and you don't need any mapping at all.

If that doesn't help for some reason, I think you need to solve your
problem in an entirely different manner.