"Can't find Hunspell dictionary" error (was Re: Emacs pretest 28.0.91 is out)

[Phil Sainty <psainty@orcon.net.nz>]

Eli Zaretskii <eliz@gnu.org> wrote:
> > From: Robert Pluim <rpluim@gmail.com>
> > Debugger entered--Lisp error: (error "Can't find Hunspell dictionary with a
> > .aff affix f...")
> >   signal(error ("Can't find Hunspell dictionary with a .aff affix f..."))
> >   error("Can't find Hunspell dictionary with a .aff affix f...")
> >   ispell-find-hunspell-dictionaries()
> >   ispell-set-spellchecker-params()
> >   ispell-valid-dictionary-list()
> >
> > This is because I have no hunspell dictionaries at all
> 
> So you want to fix this?  I don't mind, but since it's (AFAIU)
> something specific to your installation, is it important to fix on
> the release branch?

While unexpected, it doesn't seem *invalid* to have no dictionaries
installed, so I think it's weird that `ispell-valid-dictionary-list'
triggers (indirectly) an error in this scenario to essentially say
"there were no valid dictionaries", when that's also what a nil return
value would have meant.

`ispell-valid-dictionary-list' or `ispell-set-spellchecker-params'
should perhaps use `with-demoted-errors' to avoid this?

Failing that, I think guarding against this in spelling-tests.el with
`ignore-errors' makes sense.  It's an :unstable test, but it shouldn't
be triggering actual errors.


-Phil