Subject: bug#77693: 31.0.50; writing .abbrev_defs removes ‘lexical-binding’ cookie

From: Andreas Röhler <[email-masked]>
Date: Thu, 10 Apr 2025 11:24:09 +0200

With a new Emacs got warnings like

⛔ Warning (files): Missing ‘lexical-binding’ cookie in "~/.abbrev_defs".
You can add one with ‘M-x elisp-enable-lexical-binding RET’.
See ‘(elisp)Selecting Lisp Dialect’ and ‘(elisp)Converting to Lexical 
Binding’
for more information.

Fixed that by inserting the cookie.

After defining a new abbreviation and saying ‘yes’ when prompted for 
saving of the abbrev-file, the cookie is gone.

With a new Emacs the warning appears again.

In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
  3.24.33, cairo version 1.16.0) of 2025-04-10 built on kanu
Repository revision: 99a2cb05a41c66565d417e11e60f4324aaa5c5b5
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Ubuntu 22.04.5 LTS

Configured using:
  'configure --with-mailutils --with-modules -with-tree-sitter'

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

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

Major mode: Special

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
   buffer-read-only: 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 lisp-mnt 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 warnings icons 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 system-font-setting font-render-setting cairo
gtk x-toolkit xinput2 x multi-tty move-toolbar make-network-process
tty-child-frames emacs)

Memory information:
((conses 16 86381 12148) (symbols 48 16280 0) (strings 32 36162 1906)
  (string-bytes 1 582914) (vectors 16 9754)
  (vector-slots 8 116750 9047) (floats 8 25 63) (intervals 56 267 0)
  (buffers 992 11))