Re: Problems with call-process (= identifying run-python issues)

[Eli Zaretskii <eliz@gnu.org>]

> From: Juan José García-Ripoll
>  <juanjose.garciaripoll@gmail.com>
> Cc: Juan José García-Ripoll
>  <juanjose.garciaripoll@gmail.com>,
>   emacs-devel@gnu.org
> Date: Wed, 19 Aug 2020 18:23:05 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> > I have now tried this on 2 different Windows systems, one of them
> > Windows 10, and I cannot reproduce what you describe [...]
> > So I think either this is due to some local configuration issue on
> > your system, or there's some part of the reproduction recipe that you
> > omitted.
> 
> Those are the only the steps needed. I am using runemacs.exe -Q in the
> tests. I do not recall any "weird" configuration and I reproduce this
> problem with Emacs 26.3 and 27, both on my laptop.

It doesn't have to be "weird", it can be as simple as some antivirus
software or some other such stuff, they could be blocking or tweaking
cmd.exe invocations in some situations.  (Yes, in some quarters
cmd.exe invocations are considered potential security risk.)

> I am a bit at a loss at how to debug this further. Maybe I will have
> to attach a gdb while Emacs is running if that is even possible on
> Windows.

It's possible to attach GDB to Emacs on Windows, yes.

I actually looked at the source code involved in redirecting the
standard handles of subprocesses on Windows, and saw that if
redirection fails, Emacs should signal an error.  So something morfe
subtle happens in your case.  Maybe the batch file doesn't even run?