bug#42602: Wrong (not-)casechars value for "polish" in ispell-dictionary-base-alist

[Sebastian Urban <mrsebastianurban@gmail.com>]

> I don't understand this change.  Values above octal 377 cannot be
> right in the above regexps, because they are supposed to be in
> Latin-2 encoding, which is a single-byte encoding, and so can only
> handle values below octal 400.  How did you come up with those
> values?

Basically, C-x = on a char, which gave me octal values.  I though it
was recognising only A-z + ó/Ó and some other chars that I'm not
interested in, so I swapped those values for the ones corresponding to
the Polish chars.  That's the whole story.

> Anyway, I'm quite sure some other factor is at work here.

Well, I did some tests, e.g. switched back to the original value of
"polish" in my "pl" dictionary, and... it works.  And if I change from
iso-8859-2 to utf-8 in my "pl" (with original value from "polish") it
doesn't work.  So, as you later wrote - wrong character encoding,
I guess.

Looking for a cause (in default settings), I think I found it in
ispell-dictionary-base-alist and ispell-dictionary-alist.  During
"transfer" from *-base-* to ispell-dictionary-alist, the value of
CHARACTER-SET is changed in all cases from iso-* or cp1255 to utf-8,
then ispell uses these (from ispell-dictionary-alist) when it "talks"
with Aspell.

On the other hand, if I use Emacs 26.3 from Cygwin, everything works
out of the box, I don't even have to set "polish" as default
dictionary. But there, in Cygwin command line, "env | grep LANG" gives
"LANG=pl_PL.UTF-8".

> Your Emacs is a native MinGW build, whereas Aspell seems to be
> a Cygwin build?

Both Emacses are official Win builds, and Aspell is installed through
Cygwin.

> If so, you could have incompatibility in character encoding.  What
> is your Windows locale?

"Polish" everywhere in "Control Panel" -> "Regional and Language".

> And what does M-: (getenv "LANG") RET yield inside Emacs?

"PLK"


S. U.

P.S.
> Moreover, if I type in regexp-builder "[\363\323]" it won't
> recognize ó/Ó, but it doesn't have a problem with other Polish
> chars, like "ł" ("[\502]") or "ż" ("[\574]").

In the "Character List" buffer for unicode-bmp, regexp-builder
(numbers are octal values):
- 0-177 and 400-777 - highlights chars
- 240-377 - doesn't highlight chars (it highlights them if I use hex
   value, or insert them directly)
I didn't check "80h-9Fh" chars.  Chars like C-a were checked by
inserting them with quoted-insert in another buffer.