bug#50970: 29.0.50; Italics cause fill column indicator misalignment

[Carlos Pita]

That's too bad, because it means I have no reliable recipe to
reproduce and debug the problem...

Indeed it is. If you know of anything that could be affected by subtle timing issues or something like that, just let me know and I will do my best in order to test it.

Just in case, here is the dump for the minimal configuration:

In GNU Emacs 29.0.50 (build 1, x86_64-apple-darwin20.6.0, NS appkit-2022.60 Version 11.6 (Build 20G165))

 of 2021-10-02 built on Carloss-MacBook-Pro.local

Windowing system distributor 'Apple', version 10.3.2022

System Description:  macOS 11.6

Configured using:

 'configure --disable-dependency-tracking --disable-silent-rules

 --enable-locallisppath=/usr/local/share/emacs/site-lisp

 --infodir=/usr/local/Cellar/emacs-plus@28/28.0.50/share/info/emacs

 --prefix=/usr/local/Cellar/emacs-plus@28/28.0.50 --with-xml2

 --with-gnutls --without-dbus --with-imagemagick --with-modules

 --with-rsvg --with-ns --disable-ns-self-contained'

Configured features:

ACL GLIB GMP GNUTLS IMAGEMAGICK JPEG JSON LCMS2 LIBXML2 MODULES NOTIFY

KQUEUE NS PDUMPER PNG RSVG THREADS TIFF TOOLKIT_SCROLL_BARS XIM ZLIB

Important settings:

  value of $LC_CTYPE: UTF-8

  value of $LANG: en_AR.UTF-8

  locale-coding-system: utf-8-unix

Major mode: ELisp/d

Minor modes in effect:

  global-display-fill-column-indicator-mode: t

  display-fill-column-indicator-mode: t

  show-paren-mode: t

  tooltip-mode: t

  global-eldoc-mode: t

  eldoc-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

  auto-composition-mode: t

  auto-encryption-mode: t

  auto-compression-mode: t

  line-number-mode: t

  indent-tabs-mode: t

  transient-mark-mode: t

Load-path shadows:

/Users/carlos/.emacs.d/elpa/magit-20210928.1325/magit-section-pkg hides /Users/carlos/.emacs.d/elpa/magit-section-20210829.1849/magit-section-pkg

/Users/carlos/.emacs.d/elpa/transient-20210920.1038/transient hides /usr/local/Cellar/emacs-plus@28/28.0.50/share/emacs/29.0.50/lisp/transient

Features:

(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs

rfc822 mml mml-sec epa derived epg rfc6068 epg-config gnus-util rmail

rmail-loaddefs text-property-search mm-decode mm-bodies mm-encode

mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047

rfc2045 ietf-drums mm-util mail-prsvr mail-utils time-date

ido-completing-read+ memoize cus-edit pp cus-start cus-load wid-edit

minibuf-eldef ido edmacro kmacro easy-mmode

display-fill-column-indicator info package browse-url url url-proxy

url-privacy url-expand url-methods url-history url-cookie url-domsuf

url-util mailcap url-handlers url-parse auth-source cl-seq eieio

eieio-core cl-macs eieio-loaddefs password-cache json map url-vars seq

gv subr-x byte-opt bytecomp byte-compile cconv cl-loaddefs cl-lib paren

iso-transl tooltip eldoc electric uniquify ediff-hook vc-hooks

lisp-float-type elisp-mode mwheel term/ns-win ns-win ucs-normalize

mule-util 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 cl-generic 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 simple abbrev obarray cl-preloaded nadvice button

loaddefs faces cus-face macroexp files window text-properties overlay

sha1 md5 base64 format env code-pages mule custom widget

hashtable-print-readable backquote threads kqueue cocoa ns lcms2

multi-tty make-network-process emacs)

Memory information:

((conses 16 91194 5077)

 (symbols 48 10226 1)

 (strings 32 30543 1480)

 (string-bytes 1 1020041)

 (vectors 16 18443)

 (vector-slots 8 228387 13018)

 (floats 8 45 19)

 (intervals 56 253 0)

 (buffers 992 11))