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

[Eli Zaretskii]

> From: Clément Pit--Claudel <clement.pit@gmail.com>
> Date: Fri, 25 Nov 2016 02:03:38 -0500
> 
> On 2016-11-25 01:24, Fabrice Popineau wrote:
> > 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.