bug#36331: 26.2; command run using dired-do-async-shell-command cannot take any input

[Eli Zaretskii]

> Cc: 36331@debbugs.gnu.org
> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Wed, 18 May 2022 16:22:59 +0200
> 
> > First command with "*" in the command line works as expected
> >
> >        cat - * >2.txt
> >
> > With this command, the *Async Shell Command* buffer waits for us to
> > type in whatever lines that we want. When we terminate the input with
> > Control-D (EOF), the command concatenates the inputs lines with 1.txt
> > and writes the result to 2.txt.
> 
> (I'm going through old bug reports that unfortunately weren't resolved
> at the time.)
> 
> I can reproduce this, but I think that this works is more by accident
> than by design.  I don't think the `&' command is supposed to allow any
> input to the command -- at least it's not documented to.

Indeed, asynchronous commands cannot rely on being able to read and
write standard streams.  Interactive commands should not be run
asynchronously.