bug#25025: python-shell-calculate-command is wrong

[Eli Zaretskii <eliz@gnu.org>]

> From: Noam Postavsky <npostavs@users.sourceforge.net>
> Date: Fri, 25 Nov 2016 09:59:43 -0500
> Cc: Clément Pit--Claudel <clement.pit@gmail.com>, 
> 	25025@debbugs.gnu.org
> 
> >> > The python shell name is not passed to any underlying shell.
> >> > It is used to create a process, so it must not be quoted in anyway.
> >>
> >> Are you sure? Looking at the code, I see this:
> >>
> >>   (python-shell-make-comint
> >>       (or cmd (python-shell-calculate-command)) …)
> >>
> >> And python-shell-make-comint does this:
> >>
> >>   (split-string-and-unquote cmd)
> >>
> >> (ok, this is weird).  But still, if the command is "C:\Program Files\Python\python.exe", then we *do* need the shell quoting, right?
> >
> > The quoting needs to be done only where a shell command is created
> > that is about to be passed to a shell.  I believe in this case the
> > quoting is done too early.
> >
> 
> I think the whole command should be quoted with
> combine-and-quote-strings to balance the call to
> split-string-and-unquote.

Why not remove both of those calls?  Do you understand why they are
needed in that case?