From: phillip.lord@russet.org.uk (Phillip Lord)
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: Emacs-Devel devel <emacs-devel@gnu.org>
Subject: Re: disabling undo boundaries
Date: Sun, 09 Aug 2015 16:39:21 +0100 [thread overview]
Message-ID: <87pp2wmpxy.fsf@russet.org.uk> (raw)
In-Reply-To: <jwvh9o91njk.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Sat, 8 Aug 2015 17:28:28 -0400")
Stefan Monnier <monnier@iro.umontreal.ca> writes:
>>> Anyway, the patch is there. Any chance? If not, anything (further) that
>>> I can add (or remove!) to the branch to make it happen?
>> I'll try and look at it soon,
>
> IIUC this only removes the code which adds a boundary when we change
> buffer. IOW it switches from the conservative option of adding
> a boundary even if it might not be needed, to the risky option of hoping
> that someone else will add the needed boundary.
I'd tend to characterise it as the risky option of disrupting the user
experience by added unnecessary boundaries on the off-chance of using
too much memory, against the conservative option of not adding a
boundary.
But, otherwise, yes.
> As explained, this will most likely introduce problems with ever-growing
> undo-logs in buffers filled by process output and timers.
Will buffer-undo-list not be truncated by GC anyway? I can't quite
understand where the ever-growing logs come from, nor how the
functionality I have removed would prevent it.
> It's an acceptable first step, but it needs to be compensated by
> a second step which keeps track of all buffers modified during the
> execution of a command and change the "add a boundary in current-buffer
> at the end of a command" to "add boundaries in all modified buffers
> at the end of a command".
I'm struggling with understanding this also. I've tried tracing when the
code my patch removes actually runs and it is pretty rarely. And, yet,
undo works correctly, generally on a per-command basis (except for the
self-insert-command special handling).
Also, adding boundaries in all modified buffers strikes me as fairly
stochastic. Assuming a well-behaved timer (i.e. one that releases
control with `sit-for'), this logic essentially translates to "we may
choose to show an undo-boundary in at this point, or we may not".
So I'd need an example, though, or some way of causing this sort of
problem that you are worried about. A failing ert test in
test/automated would be ideal, but anything is good!
Phil
next prev parent reply other threads:[~2015-08-09 15:39 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-10 21:43 disabling undo boundaries Phillip Lord
2015-05-11 1:42 ` Stefan Monnier
2015-05-11 11:46 ` Phillip Lord
2015-05-11 14:45 ` Stefan Monnier
2015-05-11 16:31 ` Phillip Lord
2015-05-11 19:30 ` Stefan Monnier
2015-05-11 20:42 ` Phillip Lord
2015-05-11 22:23 ` Stefan Monnier
2015-05-12 11:52 ` Phillip Lord
2015-05-12 20:15 ` Stefan Monnier
2015-05-12 20:59 ` Phillip Lord
2015-05-13 12:32 ` Stefan Monnier
2015-05-13 15:40 ` Phillip Lord
2015-05-14 15:28 ` Stefan Monnier
2015-05-15 12:27 ` Phillip Lord
2015-05-15 18:08 ` Stefan Monnier
2015-05-15 19:49 ` Phillip Lord
2015-05-15 23:45 ` Stefan Monnier
2015-05-16 13:31 ` Phillip Lord
2015-05-19 11:59 ` Phillip Lord
2015-05-19 19:42 ` Stefan Monnier
2015-05-19 21:48 ` Phillip Lord
2015-05-20 2:00 ` Stefan Monnier
2015-05-20 7:45 ` Phillip Lord
2015-05-20 12:53 ` Stefan Monnier
2015-05-21 11:15 ` Phillip Lord
2015-05-21 15:44 ` Stefan Monnier
2015-05-21 17:03 ` Phillip Lord
2015-05-27 11:46 ` Phillip Lord
2015-06-29 0:46 ` Stefan Monnier
2015-08-04 14:18 ` Phillip Lord
2015-08-06 21:02 ` Phillip Lord
2015-08-06 22:20 ` Stefan Monnier
2015-08-07 13:40 ` Phillip Lord
2015-08-07 13:59 ` David Kastrup
2015-08-07 21:10 ` Phillip Lord
2015-08-08 5:39 ` David Kastrup
2015-08-08 9:58 ` Phillip Lord
2015-08-07 17:10 ` Stefan Monnier
2015-08-08 21:28 ` Stefan Monnier
2015-08-09 15:39 ` Phillip Lord [this message]
2015-08-09 16:30 ` Stefan Monnier
2015-08-09 16:50 ` Phillip Lord
2015-08-09 17:40 ` Stefan Monnier
2015-08-10 9:27 ` Phillip Lord
2015-08-10 21:21 ` Phillip Lord
2015-08-12 21:15 ` Stefan Monnier
2015-08-12 22:34 ` Phillip Lord
2015-08-13 2:23 ` Stefan Monnier
2015-08-21 9:40 ` Phillip Lord
2015-08-07 23:49 ` Davis Herring
2015-08-08 10:01 ` Phillip Lord
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