Lars Ingebrigtsen <larsi@HIDDEN>
to control <at> debbugs.gnu.org.
Full text available.Received: (at 52798) by debbugs.gnu.org; 29 Dec 2021 16:29:39 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Wed Dec 29 11:29:39 2021 Received: from localhost ([127.0.0.1]:50081 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1n2bpb-0008TC-2n for submit <at> debbugs.gnu.org; Wed, 29 Dec 2021 11:29:39 -0500 Received: from quimby.gnus.org ([95.216.78.240]:43518) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <larsi@HIDDEN>) id 1n2bpY-0008Sv-V6 for 52798 <at> debbugs.gnu.org; Wed, 29 Dec 2021 11:29:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnus.org; s=20200322; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References:Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=7/JPvC4SIg7LeEyOSSPLXkfU2eKlbSSEvIsuDIypxus=; b=k0t0ESPygOgCSrhQ9+uwAsWw3e A5v4RhfGkBE5yPh7R4yRnJgKp2fw+0r15P7dh4B47Phy6RbLN0XAFOGM1mbiqiAoFyDJ8UmYZe59C iGwSFKbNbscNRCq5b6a6Cji2PXf86cmOBlY0F7euiI/40NX851Z449IDYogdY0B1Cva4=; Received: from [84.212.220.105] (helo=xo) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from <larsi@HIDDEN>) id 1n2bpP-0007al-9j; Wed, 29 Dec 2021 17:29:29 +0100 From: Lars Ingebrigtsen <larsi@HIDDEN> To: Vladimir Panteleev <vladimir.panteleev.md@HIDDEN> Subject: Re: bug#52798: 27.2; `undo' causes `buffer-undo-list' to grow exponentially References: <CAHhfkvxmNaOHEi_P5Lww-NmxEj1+xS0HtfnT1S9ue6SO+6yy7g@HIDDEN> X-Now-Playing: Hot Chip's _Coming on Strong_: "Take Care" Date: Wed, 29 Dec 2021 17:29:26 +0100 In-Reply-To: <CAHhfkvxmNaOHEi_P5Lww-NmxEj1+xS0HtfnT1S9ue6SO+6yy7g@HIDDEN> (Vladimir Panteleev's message of "Sun, 26 Dec 2021 00:59:59 +0000") Message-ID: <87k0fn4bo9.fsf@HIDDEN> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Report: Spam detection software, running on the system "quimby.gnus.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Vladimir Panteleev <vladimir.panteleev.md@HIDDEN> writes: > As far as I can see, the undo (and undo-only) command causes > buffer-undo-list to grow exponentially. This causes information about > previous entries to eventually be displaced. Content analysis details: (-2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 52798 Cc: 52798 <at> debbugs.gnu.org, Stefan Monnier <monnier@HIDDEN> X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) Vladimir Panteleev <vladimir.panteleev.md@HIDDEN> writes: > As far as I can see, the undo (and undo-only) command causes > buffer-undo-list to grow exponentially. This causes information about > previous entries to eventually be displaced. I can reproduce this in Emacs 29, too. Perhaps Stefan has some comments; added to the CCs. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no
bug-gnu-emacs@HIDDEN:bug#52798; Package emacs.
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From: Vladimir Panteleev <vladimir.panteleev.md@HIDDEN>
Date: Sun, 26 Dec 2021 00:59:59 +0000
Message-ID: <CAHhfkvxmNaOHEi_P5Lww-NmxEj1+xS0HtfnT1S9ue6SO+6yy7g@HIDDEN>
Subject: 27.2; `undo' causes `buffer-undo-list' to grow exponentially
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Consider this Emacs Lisp script:
---
(eval-when-compile
(require 'cl-lib))
(with-current-buffer (get-buffer-create "undo-test")
;; First, insert 50 characters.
;; Place an undo boundary after every insertion.
(cl-loop repeat 50 do
(insert "x")
(undo-boundary))
;; Then, undo 50 times.
;; It doesn't matter if we use undo or undo-only.
;; We will only get into about 12 undos,
;; before the new exponentially-growing entries erase the old history.
(cl-loop repeat 50 do
(undo-only)
(message "Length is now: %S" (length buffer-undo-list))))
---
When executed with `emacs --script test.el', I see the following output:
---
Undo
Length is now: 102
Undo
Length is now: 104
Undo
Length is now: 108
Undo
Length is now: 116
Undo
Length is now: 132
Undo
Length is now: 164
Undo
Length is now: 228
Undo
Length is now: 356
Undo
Length is now: 612
Undo
Length is now: 1124
Undo
Length is now: 2148
Undo
Length is now: 4196
Undo
Length is now: 8292
No further undo information
---
As far as I can see, the undo (and undo-only) command causes
buffer-undo-list to grow exponentially. This causes information about
previous entries to eventually be displaced.
N.B.: I noticed that upping gc-cons-threshold lets it do more undos, but
it does not prevent the exponential growth issue.
I think this is a bug by itself, but it's worth mentioning that this
script is a reduced version of a different problem I'm seeing with the
"No further undo information" message; the bug described here may or may
not be the root cause of that bug.
In GNU Emacs 27.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.27,
cairo version 1.17.4)
of 2021-03-26 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.12101002
System Description: Arch Linux
Configured using:
'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
--localstatedir=/var --with-x-toolkit=gtk3 --with-xft --with-wide-int
--with-modules --with-cairo --with-harfbuzz 'CFLAGS=-march=x86-64
-mtune=generic -O2 -pipe -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2
LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'
Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON
PDUMPER LCMS2 GMP
Important settings:
value of $LC_TIME: en_DK.UTF-8
value of $LANG: en_US.UTF-8
locale-coding-system: utf-8-unix
Vladimir Panteleev <vladimir.panteleev.md@HIDDEN>:bug-gnu-emacs@HIDDEN.
Full text available.bug-gnu-emacs@HIDDEN:bug#52798; Package emacs.
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