Subject: 28.0.50; Recent change to count-lines broke gnus-cite faces

From: Kévin Le Gouguec <[email-masked]>
Date: Sat, 13 Feb 2021 12:06:11 +0100

Hello,

Since a few days ago, Gnus sometimes applies gnus-cite faces to
paragraphs below the actual citations.  For example, save the attached
article somewhere, then, from emacs -Q:

- M-x gnus-no-server
- G f /path/to/repro.mbox
- RET RET

There are a few things that seem to go wrong with fontification of
citations; for example, the line that starts with "That is a concern" is
erroneously fontified with gnus-cite-1.

I've tried to bisect this, and Git points out 2021-02-07 "Use
`line-number-at-pos' in `count-lines'" (7c5938ad7d).

When time permits, I'll start looking into what causes the bug, and
maybe whip up a test case; I figure someone more familiar with the code
might easily beat me to it though, so I'm reporting this before having
fully figured it out.

In GNU Emacs 28.0.50 (build 13, x86_64-pc-linux-gnu, GTK+ Version 3.24.24, cairo version 1.16.0)
 of 2021-02-08 built on my-little-tumbleweed
Repository revision: 9a698da7dea51a59aa9ddfb71887ac6b865883dc
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12010000
System Description: openSUSE Tumbleweed

Configured using:
 'configure --with-xwidgets --with-cairo'

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

Important settings:
  value of $LC_CTYPE: en_US.UTF-8
  value of $LC_TIME: en_GB.UTF-8
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=local
  locale-coding-system: utf-8-unix