Subject: 29.0.50; c-ts-mode doesn't play nicely with pixel-scroll-precision-mode

From: Po Lu <[email-masked]>
Date: Tue, 22 Nov 2022 21:08:30 +0800

Enable pixel-scroll-precision-mode, then open src/xterm.c.  Go to line
3439, enable c-ts-mode, and scroll up _with a trackpad_ until line 1675
becomes visible near the start of the window.  Finally, go down to line
1817: brackets will become randomly fontified in the error face.

In addition, I was expecting c-ts-mode to be quite a lot faster
fontifying during precision scrolling, but it is currently as slow as CC
Mode.  I think that is almost definitely a bug somewhere in our
tree-sitter fontification code, since emacs-lisp-mode fontifies much
faster.

In GNU Emacs 29.0.50 (build 243, x86_64-pc-linux-gnu) of 2022-11-22
 built on trinity
Repository revision: 350918e7be82fca046911073b360518173169255
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101099
System Description: Fedora Linux 37 (Workstation Edition)

Configured using:
 'configure --with-x --with-x-toolkit=no --without-cairo
 --with-dumping=unexec --cache-file=/tmp/ccache'

Configured features:
ACL DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON LCMS2
LIBSELINUX LIBSYSTEMD LIBXML2 MODULES NOTIFY INOTIFY OLDXMENU PNG RSVG
SECCOMP SOUND SQLITE3 THREADS TIFF TREE_SITTER UNEXEC WEBP X11 XDBE XFT
XIM XINPUT2 XPM ZLIB

Important settings:
  value of $LANG: en_GB.utf8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: C

Minor modes in effect:
  pixel-scroll-precision-mode: t
  tooltip-mode: t
  global-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
epg-config gnus-util mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils warnings icons c-ts-mode misearch
multi-isearch add-log log-view pcvs-util vc time-date cus-start cus-load
pixel-scroll cua-base ring subr-x vc-git diff-mode easy-mmode
vc-dispatcher bug-reference byte-opt gv bytecomp byte-compile find-func
cc-langs cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs cl-extra shortdoc text-property-search
thingatpt help-fns radix-tree help-mode sh-script rx smie treesit cl-seq
cl-loaddefs cl-lib executable 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 xinput2 x
multi-tty make-network-process emacs)

Memory information:
((conses 16 220297 20026)
 (symbols 48 27211 0)
 (strings 32 52112 2076)
 (string-bytes 1 1435642)
 (vectors 16 28133)
 (vector-slots 8 881343 40772)
 (floats 8 194 659)
 (intervals 56 19633 0)
 (buffers 992 18))