Subject: 29.0.50; [feature/tree-sitter] c-ts-mode fails to fontify a portion of a large C file

From: Eli Zaretskii <[email-masked]>
Date: Sun, 20 Nov 2022 19:55:54 +0200

To reproduce:

  emacs -Q
  Evaluate:

    (setq auto-mode-alist
	  (append
	   '(("\\.c\\'" . c-ts-mode))
	   auto-mode-alist))
    (setq treesit-max-buffer-size (* 11 1024 1024))

  C-x C-f packet-rrc.c RET

(This file is the one from bug#45248.)

  C-u 194770 M-g g

Observe that fontifications stop at this line for some reason.
Fontification reappears on line 209271.  Maybe it's because of the many
braces that appear in warning face?  Why does TS think there are syntax
errors here?  The C++ TS parser doesn't have that problem, btw.

P.S. Btw, isn't the treesit-max-buffer-size limit too low?  4 MiB?

In GNU Emacs 29.0.50 (build 31, i686-pc-mingw32) of 2022-11-20 built on
 HOME-C4E4A596F7
Repository revision: 4fa13b2d838e11cbe3b713f3172721cb61d499f3
Repository branch: feature/tree-sitter
Windowing system distributor 'Microsoft Corp.', version 5.1.2600
System Description: Microsoft Windows XP Service Pack 3 (v5.1.0.2600)

Configured using:
 'configure -C --prefix=/d/usr --with-wide-int
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -gdwarf-4 -g3''

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NOTIFY
W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: C

Minor modes in effect:
  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 text-property-search time-date subr-x mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
c-ts-mode rx treesit cl-seq vc-bzr vc-dispatcher vc-cvs vc-rcs log-view
easy-mmode pcvs-util cc-mode cc-fonts cc-guess cc-menus cc-cmds
cc-styles cc-align cc-engine cc-vars cc-defs cl-loaddefs cl-lib rmc
iso-transl tooltip eldoc paren electric uniquify ediff-hook vc-hooks
lisp-float-type elisp-mode mwheel dos-w32 ls-lisp disp-table
term/w32-win w32-win w32-vars term/common-win 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
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 w32notify w32 lcms2 multi-tty
make-network-process emacs)

Memory information:
((conses 16 71496 109093)
 (symbols 48 8917 42)
 (strings 16 25650 9189)
 (string-bytes 1 810278)
 (vectors 16 13855)
 (vector-slots 8 190997 54271)
 (floats 8 26 158)
 (intervals 40 583 684)
 (buffers 904 13))