--- Begin Message ---
|
Subject: |
31.0.50; wdired + replace-regexp only modifies the visible portion of the buffer |
|
Date: |
Wed, 04 Sep 2024 08:03:21 +0530 (IST) |
In GNU Emacs 31.0.50 (build 2, x86_64-pc-linux-gnu, X toolkit, cairo
version 1.18.0, Xaw3d scroll bars)
Repository revision: f1e29506822739208e5706b733cfd713c5f37cfd
Ref: https://lists.gnu.org/archive/html/emacs-devel/2024-09/msg00071.html
On carrying out the following steps
```
mkdir /dev/shm/test-foo -pv
for i in $(seq 1 40); do ln -sv /foo/$i /dev/shm/test-foo; done
(dired "/dev/shm/test-foo")
(wdired-change-to-wdired-mode)
(replace-regexp "foo" "bar")
```
It is seen that only the files in the visible portion of the buffer
are affeceted by the replace-regexp. The attached patch implements the
suggestion in
https://lists.gnu.org/archive/html/emacs-devel/2024-09/msg00079.html
and appears to fix the problem.
(However there still seems to be a boostrap related problem with
"Match data clobbered by buffer modification hooks" when wdired is
first loaded)
>From 05c8405a30a36098c55e4f31a1ec339719ccbcb3 Mon Sep 17 00:00:00 2001
From: Madhu <enometh@net.meer>
Date: Wed, 4 Sep 2024 06:55:44 +0530
Subject: [PATCH] * lisp/wdired.el: (wdired-change-to-wdired-mode): call
font-lock-ensure so replace-regexp with wdired-search-replace-filenames t
works on the whole buffer.
---
lisp/wdired.el | 1 +
1 file changed, 1 insertion(+)
diff --git a/lisp/wdired.el b/lisp/wdired.el
index 4b6a9c14b20..dd8b8640a89 100644
--- a/lisp/wdired.el
+++ b/lisp/wdired.el
@@ -264,6 +264,7 @@ wdired-change-to-wdired-mode
;; hidden partly, so we remove filename invisibility spec
;; temporarily to ensure filenames are visible for editing.
(dired-filename-update-invisibility-spec)
+ (font-lock-ensure)
(run-mode-hooks 'wdired-mode-hook)
(message "%s" (substitute-command-keys
"Press \\[wdired-finish-edit] when finished \
--
2.46.0.27.gfa3b914457
--- End Message ---
--- Begin Message ---
|
Subject: |
Re: bug#73018: 31.0.50; wdired + replace-regexp only modifies the visible portion of the buffer |
|
Date: |
Sat, 21 Sep 2024 12:34:12 +0300 |
> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: michael_heerdegen@web.de, enometh@meer.net, Ihor Radchenko
> <yantar92@posteo.net>, 73018@debbugs.gnu.org, juri@linkov.net
> Date: Tue, 17 Sep 2024 14:52:57 -0400
>
> >> > Since this is a regression in Emacs 30, I'd like to solve it on the
> >> > release branch. Can you suggest the safest fix you can come up with
> >> > for that purpose?
> >>
> >> Oh, yes: just remove the check.
> >
> > Whoa! We had that check there for 9 years, and it was introduced to
> > avoid crashes (see bug#23869), so removing it now, during a pretest,
> > is scary.
>
> Here's the story I see:
> In response to that bug, you proposed to add:
>
> /* Last line of defense, in case search registers were actually not
> saved (because someone else already occupied the save slots). */
> if (search_regs.start[sub] != sub_start
> || search_regs.end[sub] != sub_end)
> error ("Match data clobbered by buffer modification hooks");
>
> In the end, you added:
>
> commit 3a9d6296b35e5317c497674d5725eb52699bd3b8
> Author: Eli Zaretskii <eliz@gnu.org>
> Date: Mon Jul 4 18:34:40 2016 +0300
>
> Avoid crashes when buffer modification hooks clobber match data
>
> * src/search.c (Freplace_match): Error out if buffer modification
> hooks triggered by buffer changes in replace_range, upcase-region,
> and upcase-initials-region clobber the match data needed to be
> adjusted for the replacement. (Bug#23869)
>
> diff --git a/src/search.c b/src/search.c
> --- a/src/search.c
> +++ b/src/search.c
> @@ -2699,0 +2707,5 @@
> + if (search_regs.start[sub] != sub_start
> + || search_regs.end[sub] != sub_end
> + || search_regs.num_regs != num_regs)
> + error ("Match data clobbered by buffer modification hooks");
>
> A bit later we dropped the start/end part (for a reason I'm not sure is
> valid, since change hooks that modify the buffer should be disallowed,
> I think):
>
> commit 487498e497f8c6b6303bd5feeac83a5bcc2315af
> Author: Noam Postavsky <npostavs@gmail.com>
> Date: Sun May 16 15:19:57 2021 +0200
>
> Remove unreliable test for match data clobbering
>
> * src/search.c (Freplace_match): Don't test for change in search_regs
> start and end, this is unreliable if change hooks modify text earlier
> in the buffer (bug#35264).
>
> diff --git a/src/search.c b/src/search.c
> --- a/src/search.c
> +++ b/src/search.c
> @@ -2739,10 +2738,10 @@
> /* The replace_range etc. functions can trigger modification hooks
> (see signal_before_change and signal_after_change). Try to error
> out if these hooks clobber the match data since clobbering can
> - result in confusing bugs. Although this sanity check does not
> - catch all possible clobberings, it should catch many of them. */
> - if (! (search_regs.num_regs == num_regs
> - && search_regs.start[sub] == newstart
> - && search_regs.end[sub] == newpoint))
> + result in confusing bugs. We used to check for changes in
> + search_regs start and end, but that fails if modification hooks
> + remove or add text earlier in the buffer, so just check num_regs
> + now. */
> + if (search_regs.num_regs != num_regs)
> error ("Match data clobbered by buffer modification hooks");
>
> So the check that remains is one that wasn't even present originally.
>
> Also, IIUC the origin of the crash in bug#23869 is that we did:
>
> /* Adjust search data for this change. */
> {
> ptrdiff_t oldend = search_regs.end[sub];
>
> after running the change functions (i.e. at a time where
> `search_regs.end[sub]` might not hold the same match data and hence
> might be -1, leading to the crash).
>
> This code is different now. The only place where we use something like
> `search_regs.end[sub]` once it's possibly-clobbered is:
>
> if (case_action == all_caps)
> Fupcase_region (make_fixnum (search_regs.start[sub]),
> make_fixnum (newpoint),
> Qnil);
> else if (case_action == cap_initial)
> Fupcase_initials_region (make_fixnum (search_regs.start[sub]),
> make_fixnum (newpoint), Qnil);
>
> both of whose functions should not crash just because they're called
> with a -1. So I think the original crash should not happen nowadays,
> and this is because the "Adjust search data" part of the code was
> completely rewritten by:
>
> commit 66f95e0dabf750e9d2eff59b2bb6e593618cd48a
> Author: Noam Postavsky <npostavs@gmail.com>
> Date: Wed Jul 20 20:15:14 2016 -0400
>
> Adjust match data before calling after-change-funs
>
> It's important to adjust the match data in between calling
> before-change-functions and after-change-functions, so that buffer
> change hooks will always see match-data consistent with buffer
> content.
> (Bug #23917)
>
> * src/insdel.c (replace_range): Add new parameter ADJUST_MATCH_DATA,
> if
> true call update_search_regs. Update all callers (except
> Freplace_match) to pass 0 for the new parameter.
> * src/search.c (update_search_regs): New function, extracted from
> Freplace_match.
> (Freplace_match): Remove match data adjustment code, pass 1 for
> ADJUST_MATCH_DATA to replace_range instead.
>
> > And I don't think I understand how a single line you moved in
> > 63588775fcb could cause this check to signal an error in the scenario
> > of this bug. Can you explain?
>
> The line-move caused the modification hooks to be run at a different
> moment: we used to run them *after* the if+error check whereas now we
> run them before. The problem can probably be triggered in the old code
> as well if `case_action` is given a different value (in which case the
> `Fupcase_region` may also run the hooks, thus potentially causing the
> same change to the size of the `search_regs.start/end` arrays before the
> if+error check).
Thanks for the analysis. Call me a coward, but I don't want to make
this change on the release branch. Instead, I reverted the search.c
part of the 63588775fcb commit there (which will re-introduce
bug#65451, sigh). I did install the change you suggested on master.
And with that, I'm closing this bug.
--- End Message ---