From: "Mattias Engdegård" <mattias.engdegard@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 58168@debbugs.gnu.org, larsi@gnus.org
Subject: bug#58168: string-lessp glitches and inconsistencies
Date: Thu, 6 Oct 2022 11:05:51 +0200 [thread overview]
Message-ID: <52286A5C-D947-4279-812E-173BB44046E1@gmail.com> (raw)
In-Reply-To: <83k05fv9nv.fsf@gnu.org>
4 okt. 2022 kl. 18.24 skrev Eli Zaretskii <eliz@gnu.org>:
>> This treats unibyte format strings as if they were Latin-1 for the purpose of the error message.
>
> No, it doesn't. It shows the problematic characters as raw bytes, as
> in "%\200" (where \200 is a single character). If you see something
> different, please show the recipe.
(format-message "%\345" 0)
=> (error "Invalid format operation %å")
where the format string is a unibyte string of two bytes, % and 0xFC, yet the error treats it as the Latin-1 character å.
In fact,
(format-message "%å" 0)
yields the same error string.
>> Not very important, of course, but maybe there should be a UNIBYTE_TO_CHAR in the alternative branch?
>
> No, that would show the multibyte codepoint, and will confuse users,
> because the result would look very different from the problematic
> format spec in this case.
Yes, that's probably right. I suppose the right solution is something like:
unsigned char *p = (unsigned char *) format - 1;
if (multibyte_format)
error ("Invalid format operation %%%c", STRING_CHAR (p));
else
error (*p <= 127 ? "Invalid format operation %%%c"
: "Invalid format operation char 0x%02x",
*p);
but perhaps it's a rare error not worth the trouble. (If we don't bother changing it, a little comment saying that we are aware of the glitch may be a good idea.)
> Who said anything about #x3fffc? The original code had #xfc, the
> unibyte code for #x3ffffc.
There seems to be a misunderstanding. The original (and current) code attempts to display char #x3fffc, which is not a raw byte. It's just a typo for #x3ffffc -- not a big deal.
Of course I could have retained the 3fffc under a different label, but everyone else reading the test would just assume it was a typo of 3ffffc since 3fffc itself is not very interesting. I replaced it with 10abcd, a wide Unicode value deliberately chosen to be arbitrary-looking. We could use another value if you prefer.
> I don't see why we shouldn't test both.
> In the other problematic hunk you replaced \777774 with \374 -- why?
3fffc in octal is 777774; when changed to 3ffffc it becomes a raw byte, fc, displayed as \374.
next prev parent reply other threads:[~2022-10-06 9:05 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-29 16:24 bug#58168: string-lessp glitches and inconsistencies Mattias Engdegård
2022-09-29 17:00 ` Mattias Engdegård
2022-09-29 17:11 ` Eli Zaretskii
2022-09-30 20:04 ` Mattias Engdegård
2022-10-01 5:22 ` Eli Zaretskii
2022-10-01 19:57 ` Mattias Engdegård
2022-10-02 5:36 ` Eli Zaretskii
2022-10-03 19:48 ` Mattias Engdegård
2022-10-04 5:55 ` Eli Zaretskii
2022-10-04 17:40 ` Richard Stallman
2022-10-04 18:07 ` Eli Zaretskii
2022-10-06 9:05 ` Mattias Engdegård
2022-10-06 11:06 ` Eli Zaretskii
2022-10-07 14:23 ` Mattias Engdegård
2022-10-08 7:35 ` Eli Zaretskii
2022-10-14 14:39 ` Mattias Engdegård
2022-10-14 15:31 ` Eli Zaretskii
2022-10-17 12:44 ` Mattias Engdegård
2022-09-30 13:52 ` Lars Ingebrigtsen
2022-09-30 20:12 ` Mattias Engdegård
2022-10-01 5:34 ` Eli Zaretskii
2022-10-01 11:51 ` Mattias Engdegård
2022-10-01 10:02 ` Lars Ingebrigtsen
2022-10-01 10:12 ` Eli Zaretskii
2022-10-01 13:37 ` Mattias Engdegård
2022-10-01 13:43 ` Lars Ingebrigtsen
2022-10-03 19:48 ` Mattias Engdegård
2022-10-04 10:44 ` Lars Ingebrigtsen
2022-10-04 11:37 ` Eli Zaretskii
2022-10-04 14:44 ` Mattias Engdegård
2022-10-04 16:24 ` Eli Zaretskii
2022-10-06 9:05 ` Mattias Engdegård [this message]
2022-10-06 11:13 ` Eli Zaretskii
2022-10-06 12:43 ` Mattias Engdegård
2022-10-06 14:34 ` Eli Zaretskii
2022-10-07 14:45 ` Mattias Engdegård
2022-10-07 15:33 ` Eli Zaretskii
2022-10-08 17:13 ` Mattias Engdegård
2022-10-01 13:51 ` Eli Zaretskii
2022-10-01 5:30 ` Eli Zaretskii
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