From: Eli Zaretskii <eliz@gnu.org>
To: phillip.lord@russet.org.uk (Phillip Lord)
Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org
Subject: Re: Calling Lisp from undo.c's record_* functions
Date: Tue, 17 Nov 2015 18:35:56 +0200 [thread overview]
Message-ID: <83a8qcbn2r.fsf@gnu.org> (raw)
In-Reply-To: <87d1v8bsbf.fsf@russet.org.uk>
> From: phillip.lord@russet.org.uk (Phillip Lord)
> Cc: Eli Zaretskii <eliz@gnu.org>, <emacs-devel@gnu.org>
> Date: Tue, 17 Nov 2015 14:42:44 +0000
>
> > The "critical section" is the span of code during which the buffer is
> > "being worked on" by the insertion function, so during this time, the
> > buffer shouldn't be modified by anyone else in any way: no Elisp code
> > should be run, no GC should take place.
>
> Assuming the documentation of undo.c is rigourously followed, then this
> should only be a problem for insert. All the others say "at the
> beginning of the command" or "about to happen". Only insertion says
> "before or after". Although, record_insert calls record_point which
> rather confuses me -- surely in record_insert can be after, so can
> record_point.
I don't recommend relying on such promises too much. You can never
know if someone, some day violates it, whether consciously or
inadvertently. In fact, it looks like replace_range already does just
that.
> There are only 7 calls to record_insert so changing the so record_insert
> is *always* before would be possible.
Did you look at insert_from_gap? AFAIU, it assumes that the gap
position stays put during the call to record_insert. If that can call
Lisp or GC, that assumption is false.
> Big change to make at this point in the release cycle.
No, I don't think so. We still have several months to go.
Btw, could you perhaps write a short description of this change and
its effects in the Lisp level for etc/NEWS? I see there's not a word
about this there. Bonus points if you also update the ELisp manual.
Thanks.
next prev parent reply other threads:[~2015-11-17 16:35 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
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 [this message]
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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