Subject: 29.1; When editing a Git commit message (COMMIT_EDITMSG), "Local variables entry is missing the prefix"

From: Vincent Lefevre <[email-masked]>
Date: Thu, 19 Oct 2023 03:47:05 +0200

When editing a Git commit message (using "verbose = true"),
I got the error

File mode specification error: (user-error Local variables entry is
missing the prefix)

I suspect that this is because of

 @c Local variables:
 @c eval: (add-hook 'before-save-hook 'time-stamp nil t)
 @c time-stamp-pattern: "texinfoversion{%Y-%02m-%02d.%02H}"
-@c page-delimiter: "^\\\\message\\|emacs-page"
+@c page-delimiter: "^\\\\message"
 @c End:

in the diff.

This looks like similar to
  https://debbugs.gnu.org/cgi/bugreport.cgi?bug=13862

Shouldn't Emacs detect that this is part of a diff (where some prefix
is preceded by ' ', '+' or '-')?

In GNU Emacs 29.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.38,
 cairo version 1.16.0) of 2023-08-30, modified by Debian built on
 x86-csail-01
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: Debian GNU/Linux trixie/sid

Configured using:
 'configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/libexec
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-libsystemd --with-pop=yes
 --enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils
 --with-native-compilation --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/libexec
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-libsystemd --with-pop=yes
 --enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils
 --with-native-compilation --with-cairo --with-x=yes
 --with-x-toolkit=gtk3 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -ffile-prefix-map=/build/reproducible-path/emacs-29.1+1=.
 -fstack-protector-strong -Wformat -Werror=format-security -Wall'
 'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES
NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3
THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER WEBP X11 XDBE XIM XINPUT2
XPM GTK3 ZLIB

Important settings:
  value of $LC_COLLATE: POSIX
  value of $LC_CTYPE: C.UTF-8
  value of $LC_TIME: en_DK.utf8
  value of $LANG: POSIX
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  display-time-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-11/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-11/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-11/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-12/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-12/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-12/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-13/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-13/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-13/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-14/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-14/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-14/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-15/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-15/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-15/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-16/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-16/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-16/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-3.5/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-3.5/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-3.5/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-3.6/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-3.6/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-3.6/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-3.7/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-3.7/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-3.7/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-7/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-7/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-7/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-8/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-8/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-8/tablegen-mode
/usr/share/emacs/site-lisp/llvm-10/llvm-mode hides /usr/share/emacs/site-lisp/llvm-9/llvm-mode
/usr/share/emacs/site-lisp/llvm-10/emacs hides /usr/share/emacs/site-lisp/llvm-9/emacs
/usr/share/emacs/site-lisp/llvm-10/tablegen-mode hides /usr/share/emacs/site-lisp/llvm-9/tablegen-mode
/usr/share/emacs/site-lisp/elpa/po-mode-0.21/po-mode hides /usr/share/emacs/site-lisp/elpa-src/po-mode-0.21/po-mode
/usr/share/emacs/site-lisp/elpa/po-mode-0.21/po-mode-pkg hides /usr/share/emacs/site-lisp/elpa-src/po-mode-0.21/po-mode-pkg
/usr/share/emacs/site-lisp/elpa/po-mode-0.21/po-mode-autoloads hides /usr/share/emacs/site-lisp/elpa-src/po-mode-0.21/po-mode-autoloads
/usr/share/emacs/site-lisp/latex-cjk-thai/thai-word hides /usr/share/emacs/29.1/lisp/language/thai-word

Features:
(shadow sort mail-extr emacsbug message yank-media puny dired
dired-loaddefs rfc822 mml mml-sec epa derived epg rfc6068 epg-config
gnus-util text-property-search time-date mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils comp comp-cstr warnings
rx cl-extra help-mode cus-edit pp cus-start icons wid-edit time cus-load
cc-styles cc-align cc-engine cc-vars cc-defs mmm-auto mmm-vars mmm-utils
mmm-compat package browse-url url url-proxy url-privacy url-expand
url-methods url-history url-cookie generate-lisp-file url-domsuf
url-util mailcap url-handlers url-parse auth-source cl-seq eieio
eieio-core cl-macs password-cache json subr-x map byte-opt gv bytecomp
byte-compile url-vars 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 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 lcms2
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 146320 12417)
 (symbols 48 11840 1)
 (strings 32 34182 1685)
 (string-bytes 1 1067203)
 (vectors 16 21577)
 (vector-slots 8 669442 84004)
 (floats 8 47 28)
 (intervals 56 311 0)
 (buffers 984 12))