bug#23186: 25.0.92; Tramp: Windows does not always set COMSPEC, tramp blows up in a string-match)

[Eli Zaretskii <eliz@gnu.org>]

> From: Michael Albinus <michael.albinus@gmx.de>
> Date: Sat, 02 Apr 2016 21:47:48 +0200
> Cc: 23186@debbugs.gnu.org
> 
> If you are interested in changing Tramp according to your needs, pls be
> cooperative. Make a proposal about a config option which could be used
> instead of the COMSPEC env which doesn't exist in your environment. Make
> a proposal how to avoid calling cmd.exe at all, it seems not be
> mandatory, I believe. Propose something else what is possible.
> 
> Your first proposal, trusting C:\Windows\system32\cmd.exe, hasn't been
> accepted, by reasons Eli has given. And indeed, it looks too me like too
> much heuristic, so I'm with Eli.

I asked a question which might suggest a solution.  The idea is that
if we cannot trust COMSPEC, then we had better made sure what can we
trust in the environment, because Emacs uses the environment variable
for many other important needs, and one way of finding cmd.exe is
through other environment variables.

If the OP answers the question, we might be on a more constructive
path.