From: Akinori MUSHA <knu@iDaemons.org>
To: 37095@debbugs.gnu.org
Subject: bug#37095: [PATCH] Save match data in ucs-normalize-region
Date: Tue, 20 Aug 2019 16:18:06 +0900 [thread overview]
Message-ID: <bf33401d-0f83-bd3e-fce2-94412e84266d@iDaemons.org> (raw)
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A patch generated by git format-patch is attached below, which simply
wraps `ucs-normalize-region` with `save-match-data`.
I'm a user of the Emacs Mac port by mituharu was investigating a bug
where dired fails to open a certain local directory on macOS. The
error was raised at `replace-match` in the `insert-directory`
function:
```
(when (re-search-forward "^ *\\(total\\)" nil t)
(let ((available (get-free-disk-space ".")))
(when available
;; Replace "total" with "used", to avoid confusion.
(replace-match "total used in directory" nil nil nil 1)
```
And it turned out the match data changed after returning from
`get-free-disk-space` and that was why `replace-match` failed.
Inside of `get-free-disk-space` most platforms uses a generic method
to get the free space, and that part is fine because it is surrounded
by `save-match-data`. However, the Mac port is one of the few
platforms that implements a native 'file-system-info` function, which
is called if it exists. Then, the `file-system-info` in `src/mac.c`
calls ENCODE_FILE() on a given directory name, which in the end calls
`ucs-normalize-region` to normalize the filename, where the match data
is clobbered.
https://bitbucket.org/mituharu/emacs-mac/src/df827786d7a7fb0a0e2f27577af67e32d9a888a9/src/mac.c#lines-2337
ENCODE_FILE() is transparently called by many C functions, which means
`ucs-normalize-region` can be called at unpredictable timings, so I
think it should keep match data unchanged.
--
Akinori MUSHA / https://akinori.org/
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From 11d49adcbadcfcbe844f873e63ba1d596f72e4c5 Mon Sep 17 00:00:00 2001
From: Akinori MUSHA <knu@idaemons.org>
Date: Mon, 19 Aug 2019 23:53:50 +0900
Subject: [PATCH] Save match data in ucs-normalize-region
* lisp/international/ucs-normalize.el (ucs-normalize-region): Save
match data. This function can be transparently called via
ENCODE_FILE() when the underlying filesytem uses normalized Unicode
filenames, so it requires much care not to cause any side effects.
---
lisp/international/ucs-normalize.el | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/lisp/international/ucs-normalize.el b/lisp/international/ucs-normalize.el
index 6f1e770c09..d02d4b8e3e 100644
--- a/lisp/international/ucs-normalize.el
+++ b/lisp/international/ucs-normalize.el
@@ -514,19 +514,20 @@ ucs-normalize-region
(narrow-to-region from to)
(goto-char (point-min))
(let (start-pos starter)
- (while (re-search-forward quick-check-regexp nil t)
- (setq starter (string-to-char (match-string 0)))
- (setq start-pos (match-beginning 0))
- (ucs-normalize-block
- ;; from
- (if (or (= start-pos (point-min))
- (and (= 0 (ucs-normalize-ccc starter))
- (not (memq starter ucs-normalize-combining-chars))))
- start-pos (1- start-pos))
- ;; to
- (if (looking-at ucs-normalize-combining-chars-regexp)
- (match-end 0) (1+ start-pos))
- translation-table composition-predicate))))))
+ (save-match-data
+ (while (re-search-forward quick-check-regexp nil t)
+ (setq starter (string-to-char (match-string 0)))
+ (setq start-pos (match-beginning 0))
+ (ucs-normalize-block
+ ;; from
+ (if (or (= start-pos (point-min))
+ (and (= 0 (ucs-normalize-ccc starter))
+ (not (memq starter ucs-normalize-combining-chars))))
+ start-pos (1- start-pos))
+ ;; to
+ (if (looking-at ucs-normalize-combining-chars-regexp)
+ (match-end 0) (1+ start-pos))
+ translation-table composition-predicate)))))))
;; --------------------------------------------------------------------------------
--
2.22.0
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next reply other threads:[~2019-08-20 7:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 7:18 Akinori MUSHA [this message]
2019-08-23 3:51 ` bug#37095: [PATCH] Save match data in ucs-normalize-region Lars Ingebrigtsen
2019-08-23 5:06 ` YAMAMOTO Mitsuharu
2019-08-23 7:21 ` Akinori MUSHA
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