bug#57649: 27.1; Spell check on remote file fails on windows.

[Eli Zaretskii]

Ping!

> Cc: 57649@debbugs.gnu.org, nlongo@mathworks.com
> Date: Thu, 08 Sep 2022 20:14:00 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > Cc: "57649@debbugs.gnu.org" <57649@debbugs.gnu.org>
> > From: Michael Albinus <michael.albinus@gmx.de>
> > Date: Thu, 08 Sep 2022 17:09:27 +0200
> > 
> > > The emacs debugger gives:
> > > Debugger entered--Lisp error: (file-missing "Opening process input file" 
> > > "No such file or directory" "/plinkx:homeoffice:/home/nmichalo/NUL")
> > >   call-process("c:/NProgramFiles/bin/hunspell.exe" "NUL" t nil "-D" "-a" 
> > > "NUL")
> > >   apply(call-process ("c:/NProgramFiles/bin/hunspell.exe" "NUL" t nil 
> > > "-D" "-a" "NUL"))
> > >   ispell-call-process("c:/NProgramFiles/bin/hunspell.exe" "NUL" t nil 
> > > "-D" "-a" "NUL")
> > >   ispell-find-hunspell-dictionaries()
> > 
> > That's it. `call-process' does not support remote files.
> > 
> > I've just checked in Emacs 29, ispell.el is still using
> > `call-process'. Somebody who knows this package shall adapt, using
> > either `process-file', or working on a temporary local copy of the file
> > to be spelled.
> 
> In this case the problem is not with the file being spell-checked,
> it's with default-directory.
> 
> The file should not be an issue, since Emacs spell-checking works by
> sending buffer text to the local spell-checking process.  It should
> not matter where the buffer text came from.
> 
> So, going back to the default-directory problem, we have this:
> 
> (defmacro ispell-with-safe-default-directory (&rest body)
>   "Execute the forms in BODY with a reasonable `default-directory'."
>   (declare (indent 0) (debug t))
>   `(let ((default-directory default-directory))
>      (unless (file-accessible-directory-p default-directory)
>        (setq default-directory (expand-file-name "~/")))
>      ,@body))
> 
> And I guess the problem is with file-accessible-directory-p, which in
> this case returns non-nil, because it probes the accessibility of the
> remote directory?  So something like the below should fix the problem?
> 
> (defmacro ispell-with-safe-default-directory (&rest body)
>   "Execute the forms in BODY with a reasonable `default-directory'."
>   (declare (indent 0) (debug t))
>   `(let ((default-directory default-directory))
>      (unless (and (not (file-remote-p default-directory))
>                   (file-accessible-directory-p default-directory))
>        (setq default-directory (expand-file-name "~/")))
>      ,@body))
> 
> 
> 
>