Subject: bug#64063: smerge-mode highlight gets stuck if buffer autoreverted "delicately"

From: Konstantin Kharlamov <[email-masked]>
Date: Wed, 14 Jun 2023 14:16:47 +0300

Basically, when autorevert is on and the file reverted contains a conflict, the
conflict is highlighted. Then if you remove the conflict by external means, and
Emacs autoreverts the buffer again, the conflict highlight usually gets removed.
However, if autorevert is using `revert-buffer-insert-file-contents-delicately`,
the highlight gets stuck.

# Steps to reproduce

1. Create `/tmp/.emacs` with the following content:

    (require 'autorevert)
    ;; Do not break markers in a buffer upon reverting a buffer. Details:
    ;; https://github.com/magit/magit/issues/4442
    (setq revert-buffer-insert-file-contents-function 'revert-buffer-insert-
file-contents-delicately)
    (global-auto-revert-mode 1)

2. In a terminal, enter Emacs source-code repository, and create a conflict by
executing:

    git checkout 5cace109d2 && git cherry-pick f24ea84f430

3. Open Emacs as `HOME=/tmp emacs etc/NEWS`. Note a conflict line that Emacs
automatically jumped to.
4. In a terminal, execute `git cherry-pick --abort` and wait for Emacs to revert
the buffer. Note that buffer no longer has conflict.

## Expected

The reverted buffer does not have word "user option" highlighted

## Actual

The reverted buffer has word "user option" highlighted in red.

------------------

In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.38, cairo version 1.17.8) of 2023-05-31 built on constantine-N61Ja
Repository revision: 5cace109d2bce98a7d486e44378286031465f40f
Repository branch: fix-smerge-highlight
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: Arch Linux

Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --mandir=/usr/share/man --with-gameuser=:games
 --with-modules --without-libotf --without-m17n-flt --without-gconf
 --enable-link-time-optimization --with-native-compilation=yes
 --with-xinput2 --with-x-toolkit=gtk3 --without-xaw3d --with-sound=no
 --with-tree-sitter --without-gpm --without-compress-install
 '--program-transform-name=s/\([ec]tags\)/\1.emacs/' 'CFLAGS=-Wno-error
 -flto=2 -march=native -O3 -pipe -fno-stack-protector -fweb
 -fmerge-all-constants -fno-plt -fcommon' 'LDFLAGS=-flto=2 -O3
 -march=native -fweb -fmerge-all-constants -floop-nest-optimize
 -Wl,--sort-common,-z,relro -fno-plt -fcommon''

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

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

Major mode: Shell-script

Minor modes in effect:
  sh-electric-here-document-mode: t
  yas-global-mode: t
  yas-minor-mode: t
  company-box-mode: t
  global-git-commit-mode: t
  server-mode: t
  projectile-mode: t
  winum-mode: t
  global-color-identifiers-mode: t
  symbol-overlay-mode: t
  global-symbol-overlay-mode: t
  global-highlight-parentheses-mode: t
  highlight-parentheses-mode: t
  show-smartparens-global-mode: t
  show-smartparens-mode: t
  smartparens-global-mode: t
  smartparens-mode: t
  global-highlight-numbers-mode: t
  delete-selection-mode: t
  highlight-numbers-mode: t
  evil-goggles-mode: t
  global-evil-surround-mode: t
  evil-surround-mode: t
  shell-dirtrack-mode: t
  evil-mode: t
  evil-local-mode: t
  windmove-mode: t
  global-auto-revert-mode: t
  auto-revert-mode: t
  company-flx-mode: t
  global-company-mode: t
  company-mode: t
  override-global-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
~/.emacs.d/lisp/popup hides /home/constantine/.emacs.d/elpa/popup-
20211231.1823/popup
~/.emacs.d/lisp/idomenu hides /home/constantine/.emacs.d/elpa/idomenu-
20141123.2120/idomenu
/home/constantine/.emacs.d/elpa/cmake-mode-20220322.1258/cmake-mode hides
/usr/share/emacs/site-lisp/cmake-mode
/home/constantine/.emacs.d/elpa/ninja-mode-20181024.1439/ninja-mode hides
/usr/share/emacs/site-lisp/ninja-mode
/home/constantine/.emacs.d/elpa/transient-20220406.1156/transient hides
/usr/share/emacs/30.0.50/lisp/transient
/home/constantine/.emacs.d/elpa/use-package-20210207.1926/use-package hides
/usr/share/emacs/30.0.50/lisp/use-package/use-package
/home/constantine/.emacs.d/elpa/use-package-20210207.1926/use-package-lint hides
/usr/share/emacs/30.0.50/lisp/use-package/use-package-lint
/home/constantine/.emacs.d/elpa/use-package-20210207.1926/use-package-jump hides
/usr/share/emacs/30.0.50/lisp/use-package/use-package-jump
/home/constantine/.emacs.d/elpa/use-package-20210207.1926/use-package-ensure
hides /usr/share/emacs/30.0.50/lisp/use-package/use-package-ensure
/home/constantine/.emacs.d/elpa/use-package-20210207.1926/use-package-diminish
hides /usr/share/emacs/30.0.50/lisp/use-package/use-package-diminish
/home/constantine/.emacs.d/elpa/use-package-20210207.1926/use-package-delight
hides /usr/share/emacs/30.0.50/lisp/use-package/use-package-delight
/home/constantine/.emacs.d/elpa/use-package-20210207.1926/use-package-core hides
/usr/share/emacs/30.0.50/lisp/use-package/use-package-core
/home/constantine/.emacs.d/elpa/use-package-20210207.1926/use-package-bind-key
hides /usr/share/emacs/30.0.50/lisp/use-package/use-package-bind-key
/home/constantine/.emacs.d/elpa/bind-key-20210210.1609/bind-key hides
/usr/share/emacs/30.0.50/lisp/use-package/bind-key
/home/constantine/.emacs.d/elpa/let-alist-1.0.6/let-alist hides
/usr/share/emacs/30.0.50/lisp/emacs-lisp/let-alist

Features:
(shadow sort mail-extr emacsbug shortdoc help-fns radix-tree
emacs-news-mode woman man cua-base goto-chg dabbrev vc-hg vc-bzr vc-src
vc-sccs vc-svn vc-cvs vc-rcs log-view vc bug-reference term/xterm xterm
tabify flx quail misearch multi-isearch tramp-archive tramp-gvfs
tramp-cache time-stamp zeroconf dbus xml tramp tramp-loaddefs trampver
tramp-integration files-x tramp-compat xdg parse-time iso8601 ls-lisp
conf-mode yaml-mode dockerfile-mode smartparens-python python vimrc-mode
sh-script treesit executable smartparens-markdown markdown-mode noutline
outline yasnippet-snippets yasnippet vc-git vc-dispatcher face-remap
meson-mode smie desktop frameset smex company-box company-box-doc
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magit-pull magit-fetch magit-clone magit-remote magit-commit
magit-sequence magit-notes magit-worktree magit-tag magit-merge
magit-branch magit-reset magit-files magit-refs magit-status magit
magit-repos magit-apply magit-wip magit-log which-func imenu magit-diff
git-commit log-edit message sendmail yank-media puny dired
dired-loaddefs rfc822 mml mml-sec epa epg rfc6068 epg-config gnus-util
time-date mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047
rfc2045 mm-util ietf-drums mail-prsvr mailabbrev mail-utils gmm-utils
mailheader pcvs-util add-log magit-core magit-autorevert magit-margin
magit-transient magit-process with-editor server magit-mode transient
magit-git magit-base magit-section format-spec crm compat projectile
lisp-mnt grep compile text-property-search ibuf-ext ibuffer
ibuffer-loaddefs smerge-mode diff-mode diff derived winum
color-identifiers-mode symbol-overlay highlight-parentheses
sp-sublimetext-like smartparens-config smartparens-text smartparens
loadhist dash delsel highlight-numbers parent-mode ido emvil
evil-goggles pulse color evil-surround evil evil-keybindings
evil-integration evil-maps evil-commands reveal flyspell ispell
evil-jumps evil-command-window evil-search evil-ex shell pcomplete
comint ansi-osc ansi-color evil-types evil-macros evil-repeat
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windmove calc calc-loaddefs calc-macs thingatpt rect evil-digraphs
evil-vars use-package-ensure avy autorevert filenotify company-oddmuse
company-keywords company-etags etags fileloop generator xref project
ring company-gtags company-dabbrev-code company-dabbrev company-files
company-clang company-capf company-cmake company-semantic
company-template company-bbdb company-flx company cl-extra help-mode
use-package-bind-key use-package-core edmacro kmacro bind-key easy-mmode
cus-load string-inflection-autoloads php-mode-autoloads
elixir-mode-autoloads yaml-mode-autoloads ninja-mode-autoloads
lsp-mode-autoloads smartparens-autoloads company-flx-autoloads
flx-autoloads treepy-autoloads bitbucket-autoloads request-autoloads
vimrc-mode-autoloads posframe-autoloads company-box-autoloads
frame-local-autoloads projectile-autoloads js2-mode-autoloads
csv-mode-autoloads rx cc-styles cc-align cc-engine cc-vars cc-defs
magit-autoloads pcase magit-section-autoloads compat-autoloads
dash-autoloads company-autoloads info package browse-url url url-proxy
url-privacy url-expand url-methods url-history url-cookie
generate-lisp-file url-domsuf url-util mailcap url-handlers url-parse
auth-source cl-seq eieio eieio-core cl-macs password-cache json subr-x
map byte-opt gv bytecomp byte-compile url-vars cl-loaddefs cl-lib 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 indonesian philippine
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs theme-loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget keymap 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 native-compile emacs)

Memory information:
((conses 16 830707 760363)
 (symbols 48 33187 0)
 (strings 32 209268 43537)
 (string-bytes 1 6269384)
 (vectors 16 101229)
 (vector-slots 8 3036394 730693)
 (floats 8 456 39245)
 (intervals 56 35797 24006)
 (buffers 984 61))