From: phillip.lord@russet.org.uk (Phillip Lord)
To: Stefan Monnier <monnier@IRO.UMontreal.CA>
Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
Subject: Re: Calling Lisp from undo.c's record_* functions
Date: Tue, 17 Nov 2015 12:14:27 +0000 [thread overview]
Message-ID: <87h9kkbz6k.fsf@russet.org.uk> (raw)
In-Reply-To: <jwv4mgl36m3.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Mon, 16 Nov 2015 17:51:43 -0500")
Stefan Monnier <monnier@IRO.UMontreal.CA> writes:
>> Debugging uncovered the following sequence of calls:
>
>> . bottom line: the gap was shrunk behind the back of
>> insert_from_string_1, which totally doesn't expect that, and
>> proceeds doing silly things, like setting the gap size to a large
>> negative value, and from there we are on a certain and very short
>> path to a crash
>
> Duh!
>
>> My dilemma is: how to fix this cleanly and correctly?
>
> Not sure what's the best solution, but the precise moment when
> run_undoable_change is executed is not terribly important, so if we
> could just move it to either before or after the "critical section",
> then that would be a good solution.
I'm not sure how I would identify the "critical section".
At one point, this function call was actually a hook
(after-undoable-change-hook). Would this solve the problem?
>
>> Question #1: do we really need to call Lisp from so deep inside the
>> bowels of buffer manipulation routines? Is that safe? Perhaps we
>> should reimplement undo-auto--undoable-change inC?
>
> That should work, yes.
I've pushed an unfinished fix to fix/segfault-from-run-undoable-change
I'm pretty sure my implementation in C could be simpler. I wasn't sure
how to get from the current-buffer variable in C, to the Lisp_Object, so
in the end, I just called Fcurrent_buffer.
The second part of the plan is to change simple.el to use a idle timer,
as I suggested yesterday. I'll do that later today.
At the moment, I can't replicate the problem, though.
Phil
next prev parent reply other threads:[~2015-11-17 12:14 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-16 16:46 Calling Lisp from undo.c's record_* functions Eli Zaretskii
2015-11-16 21:51 ` Phillip Lord
2015-11-16 22:51 ` Stefan Monnier
2015-11-17 12:14 ` Phillip Lord [this message]
2015-11-17 13:46 ` Stefan Monnier
2015-11-17 14:42 ` Phillip Lord
2015-11-17 15:40 ` Stefan Monnier
2015-11-17 16:24 ` Eli Zaretskii
2015-11-17 16:49 ` Stefan Monnier
2015-11-17 17:05 ` Eli Zaretskii
2015-11-17 17:34 ` Stefan Monnier
2015-11-17 18:00 ` Eli Zaretskii
2015-11-17 19:09 ` Stefan Monnier
2015-11-17 19:22 ` Eli Zaretskii
2015-11-17 21:05 ` Phillip Lord
2015-11-17 21:02 ` Phillip Lord
2015-11-18 2:55 ` Stefan Monnier
2015-11-18 12:26 ` Phillip Lord
2015-11-17 16:35 ` Eli Zaretskii
2015-11-17 20:52 ` Phillip Lord
2015-11-18 3:38 ` Eli Zaretskii
2015-11-18 9:56 ` Phillip Lord
2015-11-18 10:49 ` David Kastrup
2015-11-18 17:30 ` Eli Zaretskii
2015-11-17 16:40 ` Eli Zaretskii
2015-11-17 16:51 ` Stefan Monnier
2015-11-17 19:44 ` Eli Zaretskii
2015-11-17 21:35 ` Phillip Lord
2015-11-18 2:52 ` Stefan Monnier
2015-11-18 3:49 ` Eli Zaretskii
2015-11-18 12:31 ` Phillip Lord
2015-11-18 17:49 ` Eli Zaretskii
2015-11-19 1:49 ` Stefan Monnier
2015-11-19 10:16 ` Phillip Lord
2015-11-19 15:53 ` Eli Zaretskii
2015-11-19 17:49 ` Stefan Monnier
2015-11-19 17:58 ` Eli Zaretskii
2015-11-19 18:17 ` Stefan Monnier
2015-11-22 21:44 ` Phillip Lord
2015-11-22 22:41 ` John Wiegley
2015-11-23 17:29 ` Phillip Lord
2015-11-23 3:37 ` Eli Zaretskii
2015-11-23 17:28 ` Phillip Lord
2015-11-25 17:43 ` Eli Zaretskii
2015-11-25 22:51 ` Richard Stallman
2015-11-26 10:27 ` Phillip Lord
2015-11-17 21:13 ` Phillip Lord
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