bug#59545: 29.0.50; Eshell fails to redirect output of sourced eshell file

[Michael Albinus <michael.albinus@gmx.de>]

Jim Porter <jporterbugs@gmail.com> writes:

Hi Jim,

> Eli, this is the patch for the release branch (it corresponds to part
> 0003 of the patch series for master). Is this ok to merge? It's a
> regression that was introduced in Emacs 28.1, and the fix is pretty
> simple.
>
> From b04f42cca272b9a0f3b5e3167ce956523b161a7e Mon Sep 17 00:00:00 2001
> From: Jim Porter <jporterbugs@gmail.com>
> Date: Tue, 20 Dec 2022 16:20:50 -0800
> Subject: [PATCH] When redirecting to the null device in Eshell, use
>  "/dev/null"
>
> This is so that users can type "cmd ... > /dev/null" in Eshell no
> matter what their system's null device is called.  This partially
> reverts 67a8bdb90c9b5865b7f17290c7135b1a5458c36d.

And when they want to use another value? (null-device) returns
"/dev/null" for local default-directory's if you're not on MS
Windows. On MS Windows, it returns "NUL".

With a remote default-directory, the value is configurable (as
connection-local variable). Per default it is also "/dev/null", but it
could be changed.

Do you want to suppress this mechanism in Eshell? Why? I guess it is
more appropriate to install a handler for the actual value of
(null-device), instead just a handler for "/dev/null" only. And if you
want to make "/dev/null" a system-independant default, add the same
handler for this in parallel. Then both would be equivalent on MS Windows:

--8<---------------cut here---------------start------------->8---
cmd ... > /dev/null
cmd ... > NUL
--8<---------------cut here---------------end--------------->8---

Best regards, Michael.