Subject: comment-or-uncomment-region breaks buffer-undo-list on visiting file

From: Rittwik Chatterjee <[email-masked]>
Date: Sat, 12 Aug 2023 19:01:17 +0530

From: Rittwik Chatterjee <[email-masked]>
To: [email-masked]
Subject: 29.1; comment-or-uncomment-region breaks buffer-undo-list on
visiting file
Date: Sat, 12 Aug 2023 18:58:00 +0530
Message-ID: <[email-masked]
--text follows this line--

1. emacs -Q
2. C-x C-f and visit any file
3. select any region (using mouse or keyboard)
4. M-x comment-or-uncomment-region
   I get the message "combine-change-calls: buffer-undo-list broken"

Interstingly, if I select anything in scratch buffer and run
comment-or-uncomment-region everything is fine.
It seems that the bug is affecting only when I am visiting a "real" file.

In GNU Emacs 29.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.38,
cairo version 1.17.8)
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: ArcoLinux

Configured using:
 'configure --sysconfdir=/etc --prefix=/usr --libexecdir=/usr/lib
 --with-tree-sitter --localstatedir=/var --with-cairo
 --disable-build-details --with-harfbuzz --with-libsystemd
 --with-modules --with-x-toolkit=gtk3 'CFLAGS=-march=x86-64
 -mtune=generic -O2 -pipe -fno-plt -fexceptions -Wp,-D_FORTIFY_SOURCE=2
 -Wformat -Werror=format-security -fstack-clash-protection
 -fcf-protection -g
 -ffile-prefix-map=/build/emacs/src=/usr/src/debug/emacs -flto=auto'
 'LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now -flto=auto''

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY INOTIFY
PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS
TREE_SITTER WEBP X11 XDBE XIM XINPUT2 XPM GTK3 ZLIB

Important settings:
  value of $LC_MONETARY: en_US.UTF-8
  value of $LC_NUMERIC: en_US.UTF-8
  value of $LC_TIME: en_US.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
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mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
cl-loaddefs cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils rmc iso-transl tooltip cconv eldoc paren electric
uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel
term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch easymenu
timer select scroll-bar mouse jit-lock font-lock syntax font-core
term/tty-colors frame minibuffer nadvice seq simple cl-generic
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theme-loaddefs faces cus-face macroexp files window text-properties
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hashtable-print-readable backquote threads dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting cairo
move-toolbar gtk x-toolkit xinput2 x multi-tty make-network-process
emacs)

Memory information:
((conses 16 36264 9073)
 (symbols 48 5151 0)
 (strings 32 13156 2189)
 (string-bytes 1 374069)
 (vectors 16 9325)
 (vector-slots 8 148981 13250)
 (floats 8 21 23)
 (intervals 56 238 0)
 (buffers 984 10))