bug#32319: 27.0.50; flyspell-mode error on start

[Eli Zaretskii <eliz@gnu.org>]

> From: Eric Abrahamsen <eric@ericabrahamsen.net>
> Date: Mon, 30 Jul 2018 12:42:24 -0700
> 
> 
> Turning on flyspell-mode started giving me an error a few days ago, on
> two different machines I use. Both are Arch linux, both running Emacs
> master.
> 
> My only ispell customizations:
> 
> (setq ispell-program-name (executable-find "hunspell"))
> (setq ispell-personal-dictionary "~/.aspell.en_US.pws")
> 
> Starting flyspell-mode gives me:
> 
> Debugger entered--Lisp error: (wrong-type-argument stringp nil)
>   string-match("," nil 0)
>   split-string(nil "," t)
>   ispell-parse-hunspell-affix-file(nil)
>   ispell-hunspell-fill-dictionary-entry(nil)
>   ispell-start-process()
>   ispell-init-process()
>   ispell-buffer-local-words()
>   ispell-accept-buffer-local-defs()
>   flyspell-accept-buffer-local-defs(force)
>   flyspell-mode-on()
> 
> >From "emacs -Q", setting `ispell-program-name' to (executable-find
> "hunspell") (the first line of my customizations above) is sufficient to
> trigger the error.

You mean, just evaluating

  (setq ispell-program-name (executable-find "hunspell"))

signals an error??

> `ispell-current-dictionary' seems to be nil during the whole process,
> which causes the eventual error.

Yes, and you need to find out why does that happen.  FWIW, I cannot
reproduce the problem here.  Is ispell-internal-change-dictionary
called when you start spell-checking?  What if you manually set the
dictionary with "M-x ispell-change-dictionary"?

> The Hunspell version on Arch is "1.6.2", which is the value of
> `ispell-really-hunspell'.

Did you upgrade Hunspell lately?

If nothing gives a clue, I'm afraid you will have to step in a
debugger through the ispell.el initialization code and see what's
going wrong there.