bug#39483: 27.0.60; ispell ignores syntax/category tables word boundaries

["Paul W. Rankin" <hello@paulwrankin.com>]

Hello,

It appears that the function `ispell-get-word' makes its own judgements
on word boundaries, ignoring the buffer's syntax tables and character
categories. This becomes a problem with using `electric-quote-mode' and
ispell, because contractions are parsed as separate words. e.g. Calling
`ispell-word' for "doesn’t" returns:

    T is correct

To reproduce:

1. emacs -Q
2. (in *scratch*) M-x text-mode RET
3. enter text "doesn’t" (i.e. "doesn" C-x 8 ] "t")
4. M-: (modify-syntax-entry ?’ "w")
5. M-: (modify-category-entry ?’ ?^)
6. M-$ | ispell-word

Expected results:

Given the above syntax and category tables, M-f | forward-word and M-b |
backward-word now consider "doesn’t" as a single word, and so should
should be passed to the `ispell-program-name' and produce the same
result as when checked on the command line:

    % echo "doesn’t" | aspell -a
    @(#) International Ispell Version 3.1.20 (but really Aspell 0.60.8)
    *
    % echo "doesn’t" | enchant-2 -a
    @(#) International Ispell Version 3.1.20 (but really Enchant 2.2.7)
    *

Actual results:

The word "doesn’t" is parsed as "t":
    T is correct

Attempts at workarounds:

I've tried altering slot 3 of the corresponding `ispell-dictionary-base-alist'
entries from "[']" to "['’]" to no avail.

Setup:

GNU Emacs 27.0.60 (build 2, x86_64-apple-darwin19.3.0, NS appkit-1894.30
Version 10.15.3 (Build 19D76)) of 2020-02-05

-- 
Paul W. Rankin
https://www.paulwrankin.com