bug#69795: 29.1; cmdproxy.exe exits automatically after executing MSYS2 commands

[Eli Zaretskii <eliz@gnu.org>]

tags 69795 notabug
thanks

> From: awrhygty@outlook.com
> Date: Thu, 14 Mar 2024 19:55:27 +0900
> 
> 
> I have installed MSYS2 commands.
> When executing some MSYS2 commands in shell-mode buffer,
> cmdproxy.exe exits unintentionally.
> 
> The log below has two prompt strings('c:\tmp>'), but the second one is
> displayed with "Process shell finished" simultaneously.

This is not an Emacs bug.  MSYS2 programs are subtly incompatible with
the native Windows build of Emacs, and some of those incompatibilities
are indeed in the area of running subprocesses and capturing their
output.  In particular, cmdproxy tries hard to accommodate Cygwin and
MSYS programs, but is rarely used with them, and no one stepped
forward to maintain such a combination and keep in good working order
as Cygwin and MSYS evolve.  Another bunch of problems is in the area
of text encoding and decoding: Cygwin and MSYS use UTF-8 by default,
something native Windows doesn't yet support well enough.  It is
possible that the problem you show was due to this latter issue, since
'ls' displays a non-ASCII file name there.

If you want to run MSYS or Cygwin programs from Emacs, my suggestion
is to use the Cygwin build of Emacs.  There are two configurations for
that: either use the Cygwin X server, or use the w32 "toolkit"; the
latter possibility has the look-and-feel very similar to the native
Windows build, so maybe you will prefer it.

Other than that, running MSYS programs from a native build of Emacs
should be considered "not really supported".