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bug#23949: 25.0.95; Regression in handling error caused by (string-match
From: |
Stefan Monnier |
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 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) |
>> > 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
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), (continued)
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Stefan Monnier, 2016/07/12
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Kaushal Modi, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Stefan Monnier, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Eli Zaretskii, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Eli Zaretskii, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Eli Zaretskii, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Stefan Monnier, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Eli Zaretskii, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil),
Stefan Monnier <=
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Eli Zaretskii, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Stefan Monnier, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Andreas Schwab, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Eli Zaretskii, 2016/07/13
- bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil), Andreas Schwab, 2016/07/12