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 12:41:30 -0400 [thread overview]
Message-ID: <jwvlh15sdfo.fsf-monnier+emacsbugs@gnu.org> (raw)
In-Reply-To: <83shvd8qbm.fsf@gnu.org> (Eli Zaretskii's message of "Wed, 13 Jul 2016 19:18:05 +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.
> No, they aren't. They run from the debugger.
I guess it depends what you call "run when string-match is called".
For me, I look at the C backtrace and see that Fstring_match calls
functions which end up calling the debugger which ends up running
the rest.
>> >> > (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.
> What about the suggestion made by Andreas?
I think that would also fix this problem, yes. It won't fix other
possible cases where the string-match could end up running Elisp code,
but AFAIK there aren't any currently.
> Exactly. And we are punishing the innocent (the calls that don't
> signal an error) for fear of the guilty (those that do).
Right. A more efficient solution would be to implement string-match-p
in C alongside string-match rather than on top of it, so we can get rid of
inhibit-changing-match-data (replaced by some other mechanism to
propagate this info where we need it). But it's more work.
Stefan
next prev parent reply other threads:[~2016-07-13 16:41 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
2016-07-13 16:18 ` Eli Zaretskii
2016-07-13 16:41 ` Stefan Monnier [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=jwvlh15sdfo.fsf-monnier+emacsbugs@gnu.org \
--to=monnier@iro.umontreal.ca \
--cc=23949@debbugs.gnu.org \
--cc=eliz@gnu.org \
--cc=kaushal.modi@gmail.com \
--cc=schwab@suse.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.