Re: master 63d084d4e4: Fix encoding and decoding of process I/O in Eshell on Windows

[Eli Zaretskii <eliz@gnu.org>]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: emacs-devel@gnu.org
> Date: Mon, 17 Oct 2022 17:11:07 +0200
> 
> >>>>> On Mon, 17 Oct 2022 18:01:57 +0300, Eli Zaretskii <eliz@gnu.org> said:
> 
>     >> From: Robert Pluim <rpluim@gmail.com>
>     >> Cc: Eli Zaretskii <eliz@gnu.org>
>     >> Date: Mon, 17 Oct 2022 16:42:35 +0200
>     >> 
>     >> >>>>> On Sat, 15 Oct 2022 07:01:02 -0400 (EDT), Eli Zaretskii <eliz@gnu.org> said:
>     Eli> (process-environment (eshell-environment-variables))
>     Eli> +         (coding-system-for-read coding-system-for-read)
>     Eli> +         (coding-system-for-write coding-system-for-write)
>     >> 
>     >> Isnʼt passing `:coding' to `make-process' preferred to binding
>     >> `coding-system-for-{read,write}'? It has less of a global effect.
> 
>     Eli> But I _want_ a more global effect here.
> 
> You do? I thought the whole point was to influence the coding system
> used by `make-process', which you can do by passing in :coding.

The case for using :coding here is quite weak:

  . the let-binding in this case is restricted to creation of the
    processes, so here it doesn't have more "global" effect that
    :coding
  . there are two processes being created, not one; let-binding
    affects both of them, whereas :coding would have to be applied to
    each one separately
  . :coding overrides coding-system-for-read/write, which is somewhat
    surprising and perhaps unexpected; while we could have code that
    sets :coding only if coding-system-for-read/write are nil, it
    would be a trickier code, and perhaps not self-explanatory without
    a suitable commentary

Now let me turn the table and ask you why is :coding preferred, in
your opinion?