Subject: 29.0.50; Infinite loop in `pixel-fill--fill-line'

From: OGAWA Hirofumi <[email-masked]>
Date: Sat, 04 Dec 2021 16:26:37 +0900

(with-temp-buffer
  (require 'gnus-art)
  (set-fontset-font nil 'ascii "-*-DejaVu Sans Mono-*-12-*-*")
  (set-frame-width nil 80)
  (insert (propertize "Reply-To: \"no-reply\" <[email-masked]>" 'face 'gnus-header))
  (goto-char (point-min))
  (pixel-fill-region (point) (point-max) (pixel-fill-width)))

Above simplified reproduce code never be returned from
`pixel-fill--fill-line'. The following is an annotated code by some
debug while reproducing.

    (while (not (eolp))  ; (eolp) => nil, (not ...) => t
      ;; We have to do some folding.  First find the first previous
      ;; point suitable for folding.
      (if (or (not (pixel-fill-find-fill-point (line-beginning-position)))
                  ; (pixel-fill-find-fill-point ...) => nil
	      (= (point) start))
	  ;; We had unbreakable text (for this width), so just go to
	  ;; the first space and carry on.
	  (progn
	    (beginning-of-line)
	    (skip-chars-forward " ")
	    (search-forward " " (line-end-position) 'move)))
      ;; Success; continue.
      (when (= (preceding-char) ?\s) ; (preceding-char) => 62, (= ...) => nil
	(delete-char -1))
      (unless (eobp) ; (eobp) => t
        (insert ?\n)
        (when (> indentation 0)
          (insert (propertize " " 'display
                              (list 'space :align-to (list indentation))))))
      (setq start (point)) ; (point) => 96
      (pixel-fill--goto-pixel width)))) ; width => 545, (point) => 95

Thanks.

In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo version 1.16.0)
 of 2021-12-04 built on devron
Repository revision: be1359884f68a3c8f8041be5579e6c5268d42d9a
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: Debian GNU/Linux bookworm/sid

Configured using:
 'configure --with-x-toolkit=gtk3 --without-xim --with-imagemagick
 --with-wide-int --with-native-compilation --with-xinput2'

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

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

Major mode: Group

Minor modes in effect:
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  gnus-undo-mode: t
  flycheck-pos-tip-mode: t
  global-flycheck-mode: t
  global-company-mode: t
  company-mode: t
  auto-insert-mode: t
  yas-global-mode: t
  yas-minor-mode: t
  electric-pair-mode: t
  savehist-mode: t
  icomplete-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  column-number-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t

Load-path shadows:
/usr/local/share/emacs/site-lisp/git-modes/git-modes-autoloads hides /usr/local/share/emacs/site-lisp/elpa/git-modes-20211020.2306/git-modes-autoloads

Features:
(shadow bbdb-message mailalias emacsbug sendmail mule-util sort
gnus-cite shr-color color mm-archive mail-extr gnus-async gnus-bcklg
bbdb-gnus-aux qp gnus-ml disp-table hl-line elfeed-show elfeed-search
bookmark elfeed-csv elfeed elfeed-curl elfeed-log elfeed-db elfeed-lib
thingatpt avl-tree url-queue xml-query gnus-topic pp url-http url-gw
url-cache utf-7 epa-file gnutls network-stream nsm nnfolder bbdb-gnus
nnnil bbdb-mua spam spam-stat bbdb-com crm bbdb bbdb-site timezone
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gnus-score score-mode nnvirtual nntp gnus-cache gnus-msg gnus-art mm-uu
mml2015 mm-view mml-smime smime dig gnus-sum shr pixel-fill kinsoku svg
dom nndraft nnmh gnus-xoauth2 oauth2-ext plstore gnus-group gnus-undo
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netrc nnoo parse-time iso8601 gnus-spec gnus-int gnus-range message
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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 396829 121763)
 (symbols 48 24976 7)
 (strings 32 200050 13106)
 (string-bytes 1 7537649)
 (vectors 16 91875)
 (vector-slots 8 1734585 70232)
 (floats 8 9633 409)
 (intervals 56 1788 826)
 (buffers 992 27))

-- 
OGAWA Hirofumi <[email-masked]>