Subject: bug#79249: 30.2; Fonts in Emacs 30.2 vs 30.1

From: Jeremy Bryant <[email-masked]>
Date: Mon, 18 Aug 2025 21:19:28 +0100

Eli Zaretskii <[email-masked]> writes:

>> Emacs 30.1:
>> (length (font-family-list))
>> 3719
>> 
>> Emacs 30.2:
>> (length (font-family-list))
>> 151
>
> Is this in "emacs -Q"?  If so, what is your Emacs configuration?  You
> haven't posted any of the details collected by report-emacs-bug about
> your platform and Emacs build, so it's hard to think about possible
> reasons.

True, the initial bug report wasn't complete and truncated due to the
  mailer.  See full details below.

> Also, did you build both Emacs 30.1 and 30.2 with the same
> configure-time options and the same optional features?

Yes, the same.

The problem is with emacs -Q
It is the same config on both 30.1 and 30.2

./configure CFLAGS='-O2 -g3' --with-native-compilation=aot --with-x-toolkit=lucid

>> Is the font subsystem different in 30.2?
>
> It isn't supposed to be different, and on my system I get the same
> length of the list.
>
> Are you sure this is not some local configuration issue related to how
> Fontconfig (assuming your build uses it) reports fonts to Emacs?  Or
> maybe something changed on your system between these two builds?

What is Fontconfig?

Incidentally, I observe, it seems the code font-family-list is
frame-specific code, so perhaps so wider frame code was changed.

OTOH, it could well be system-specific.  The system underwent an upgrade from
Debian 12 to Debian 13, otherwise the problem between 30.2 and 30.1 is
occurring on this same system.

> If nothing else gives a clue, can you bisect on the release branch
> between the "emacs-30.1" and "emacs-30.2" tags?  I've looked at the
> commit log message and couldn't find any change which could affect
> that, but maybe it's something completely unintended and not obvious.

Thanks, for the ideas, I'll keep investigating.

In the meantime, details below.

In GNU Emacs 30.2 (build 2, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll
 bars) of 2025-08-15 built on 
Windowing system distributor 'The X.Org Foundation', version 11.0.12101016
System Description: Debian GNU/Linux 13 (trixie)

Configured using:
 'configure 'CFLAGS=-O2 -g3' --with-native-compilation=aot
 --with-x-toolkit=lucid'

Configured features:
ACL DBUS GIF GMP GNUTLS GPM JPEG LIBSELINUX LIBSYSTEMD LIBXML2 MODULES
NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG SECCOMP SOUND THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP X11 XAW3D XDBE XIM XPM LUCID ZLIB

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

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
()  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
  minibuffer-regexp-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 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 subr-x
cl-loaddefs cl-lib 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 touch-screen 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
dynamic-setting x-toolkit x multi-tty move-toolbar make-network-process
native-compile emacs)

Memory information:
((conses 16 50465 9464) (symbols 48 5828 0) (strings 32 15059 1743)
 (string-bytes 1 419662) (vectors 16 9630)
 (vector-slots 8 164629 10566) (floats 8 24 2) (intervals 56 260 2)
 (buffers 992 10))