From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Eli Zaretskii <eliz@gnu.org>
Cc: schwab@suse.de, 23949@debbugs.gnu.org, kaushal.modi@gmail.com
Subject: bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil)
Date: Wed, 13 Jul 2016 12:00:40 -0400 [thread overview]
Message-ID: <jwvk2gpttva.fsf-monnier+emacsbugs@gnu.org> (raw)
In-Reply-To: <8360s9a7ts.fsf@gnu.org> (Eli Zaretskii's message of "Wed, 13 Jul 2016 18:14:39 +0300")
>> > I also think that the "breaks a lot of Elisp code" part is at least a
>> > tad exaggerated.
>> Binding inhibit-changing-match-data to t will pretty much break any
>> function that uses match-beginning or match-end.
> But those functions aren't supposed to run when string-match is
> called.
Yet they are in bug#23949.
In practice, there's always a discrepancy between what is supposed to
happen and what can happen in the general case ;-)
>> > (defsubst string-match-p (regexp string &optional start)
>> > "\
>> > Same as `string-match' except this function does not change the match data."
>> > (condition-case err
>> > (let ((inhibit-changing-match-data t))
>> > (string-match regexp string start))
>> > (error (signal (car err) (cdr err)))))
>> That will still cause the same problems when debug-on-signal is non-nil.
> So you don't consider this an improvement that should be installed?
No.
A simpler and more robust solution would be
(save-match-data (string-match regexp string start))
Of course, with either solution, it means that string-match-p is even
worse in terms of efficiency, whereas the unsuspecting coder would
rightfully expect string-match-p to be (slightly) *more* efficient than
string-match.
Stefan
next prev parent reply other threads:[~2016-07-13 16:00 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-06 1:56 bug#24166: With --eval, errors in string-match-p do not produce backtraces (but errors in string-match do?!) Clément Pit--Claudel
2016-08-06 2:15 ` npostavs
2016-08-06 3:03 ` Clément Pit--Claudel
2016-08-06 7:25 ` Eli Zaretskii
2016-08-06 10:28 ` Noam Postavsky
2016-08-06 10:34 ` Eli Zaretskii
2016-08-06 10:49 ` Noam Postavsky
2016-08-06 11:19 ` Eli Zaretskii
2016-08-06 12:25 ` npostavs
2016-08-07 14:12 ` Eli Zaretskii
2016-08-07 14:27 ` npostavs
2016-07-11 20:12 ` bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil) Kaushal Modi
2016-07-12 12:29 ` Kaushal Modi
2016-07-12 13:14 ` Eli Zaretskii
2016-07-12 13:33 ` Kaushal Modi
2016-07-12 13:37 ` Kaushal Modi
2016-07-12 14:03 ` Eli Zaretskii
2016-07-12 14:01 ` Eli Zaretskii
2016-07-12 18:35 ` Kaushal Modi
2016-07-12 18:55 ` Noam Postavsky
2016-07-12 19:00 ` Kaushal Modi
2016-07-12 19:12 ` Eli Zaretskii
2016-07-12 19:10 ` Eli Zaretskii
2016-07-12 19:19 ` Eli Zaretskii
2016-07-12 19:29 ` Kaushal Modi
2016-07-12 20:27 ` Stefan Monnier
2016-07-13 13:10 ` Kaushal Modi
2016-07-13 13:59 ` Stefan Monnier
2016-07-13 15:06 ` Eli Zaretskii
2016-07-13 15:03 ` Eli Zaretskii
2016-07-13 14:24 ` Eli Zaretskii
2016-07-13 14:48 ` Stefan Monnier
2016-07-13 15:14 ` Eli Zaretskii
2016-07-13 16:00 ` Stefan Monnier [this message]
2016-07-13 16:18 ` Eli Zaretskii
2016-07-13 16:41 ` Stefan Monnier
2016-07-13 15:03 ` Andreas Schwab
2016-07-13 15:17 ` Eli Zaretskii
2016-07-12 14:15 ` Andreas Schwab
[not found] ` <handler.23949.C.147058007223290.notifdonectrl.2@debbugs.gnu.org>
2016-08-09 15:56 ` bug#23949: acknowledged by developer (Re: bug#24166: With --eval, errors in string-match-p do not produce backtraces (but errors in string-match do?!)) Kaushal Modi
2016-08-07 15:43 ` bug#24166: With --eval, errors in string-match-p do not produce backtraces (but errors in string-match do?!) Clément Pit--Claudel
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