where I called `vc-root-diff' from the root of an clone of emacs Git repository after I ran the following commands: matthias@carbon:~/Sources/emacs$ git status Sur la branche master Votre branche est à jour avec 'origin/master'. rien à valider, la copie de travail est propre matthias@carbon:~/Sources/emacs$ touch empty.py matthias@carbon:~/Sources/emacs$ git add empty.py As one can see from the "git diff" output, there's no line with "---" nor "+++" signs as expected in the implementation of `diff--font-lock-prettify': matthias@carbon:~/Sources/emacs$ git diff --cached diff --git a/empty.py b/empty.py new file mode 100644 index 0000000000..e69de29bb2 Note that empty "__init__.py" files are quite common in Python based projects. In GNU Emacs 29.0.50 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.24, cairo version 1.16.0) of 2022-02-15 built on carbon Repository revision: c4ca19e7eb6ed25b1f38f614ef0c2bbb7df12bc3 Repository branch: master Windowing system distributor 'The X.Org Foundation', version 11.0.12011000 System Description: Debian GNU/Linux 11 (bullseye) Configured using: 'configure --with-native-compilation' 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 WEBP X11 XDBE XIM XPM GTK3 ZLIB Important settings: value of $LANG: fr_FR.UTF-8 value of $XMODIFIERS: @im=ibus locale-coding-system: utf-8-unix Major mode: Summary Minor modes in effect: highlight-changes-visible-mode: t shell-dirtrack-mode: t minions-mode: t global-company-mode: t company-mode: t desktop-save-mode: t save-place-mode: t electric-pair-mode: t icomplete-mode: t global-so-long-mode: t global-auto-revert-mode: t auto-insert-mode: t tooltip-mode: t global-eldoc-mode: t show-paren-mode: t electric-layout-mode: t electric-indent-mode: t mouse-wheel-mode: t tab-bar-mode: t file-name-shadow-mode: t context-menu-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t window-divider-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t buffer-read-only: t line-number-mode: t indent-tabs-mode: t transient-mark-mode: t Load-path shadows: /home/matthias/.config/emacs/elpa/transient-20220130.1941/transient hides /usr/local/share/emacs/29.0.50/lisp/transient /home/matthias/.config/emacs/elpa/dictionary-20201001.1727/dictionary hides /usr/local/share/emacs/29.0.50/lisp/net/dictionary Features: (shadow emacsbug sendmail sort smiley gnus-cite mm-archive mail-extr textsec uni-scripts idna-mapping ucs-normalize uni-confusable textsec-check gnus-bcklg gnus-async gnus-ml disp-table gnus-topic nndraft nnmh nnfolder utf-7 epa-file gnutls network-stream nsm gnus-agent gnus-srvr gnus-score score-mode nnvirtual gnus-msg gnus-cache image-dired woman man dabbrev sh-script executable mhtml-mode css-mode hideshow cap-words superword subword js generic meson-mode smie misearch multi-isearch conf-mode yaml-mode make-mode rng-xsd xsd-regexp rng-cmpct rng-nxml rng-valid nxml-mode nxml-outln nxml-rap sgml-mode facemenu rst smerge-mode diff whitespace hl-line add-log log-view pcvs-util follow mule-util bug-reference flyspell ox-odt rng-loc rng-uri rng-parse rng-match rng-dt rng-util rng-pttrn nxml-parse nxml-ns nxml-enc xmltok nxml-util ox-latex ox-icalendar org-agenda ox-html table ox-ascii ox-publish ox goto-addr org-element avl-tree ol-eww eww xdg url-queue mm-url ol-rmail ol-mhe ol-irc ol-info ol-gnus nnselect gnus-art mm-uu mml2015 mm-view mml-smime smime dig gnus-sum shr pixel-fill kinsoku svg dom ol-docview doc-view jka-compr image-mode exif ol-bibtex ol-bbdb ol-w3m ol-doi org-link-doi dired-aux display-line-numbers hilit-chg vc-mtn vc-hg vc-bzr vc-src vc-sccs vc-svn vc-cvs vc-rcs python vc-dir vc bash-completion shell eglot array jsonrpc ert ewoc debug backtrace flymake-proc flymake compile imenu company-oddmuse company-keywords company-etags etags fileloop generator xref project company-gtags company-dabbrev-code company-dabbrev company-files company-clang company-capf company-cmake company-semantic company-template company-bbdb avoid minions company pcase carbon-custom cus-edit cus-load gnus-demon nntp gnus-group gnus-undo gnus-start gnus-dbus dbus xml gnus-cloud nnimap nnmail mail-source utf7 netrc parse-time gnus-spec gnus-win nnoo gnus-int gnus-range message yank-media rmc puny rfc822 mml mml-sec epa derived epg rfc6068 epg-config mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mailabbrev gmm-utils mailheader gnus nnheader gnus-util mail-utils range mm-util mail-prsvr wid-edit gnus-dired dired-x dired dired-loaddefs org-capture org-refile org ob ob-tangle ob-ref ob-lob ob-table ob-exp org-macro org-footnote org-src ob-comint org-pcomplete pcomplete comint ansi-color ring org-list org-faces org-entities org-version ob-emacs-lisp ob-core ob-eval org-table oc-basic bibtex iso8601 time-date ol org-keys oc org-compat org-macs org-loaddefs format-spec find-func cal-menu calendar cal-loaddefs dictionary link connection advice markdown-mode edit-indirect color thingatpt noutline outline skeleton find-file vc-git diff-mode easy-mmode vc-dispatcher ispell comp comp-cstr warnings rx cl-extra help-mode desktop frameset server bookmark text-property-search pp saveplace elec-pair icomplete so-long autorevert filenotify autoinsert cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs generic-x face-remap proof-site proof-autoloads 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 iso-transl tooltip 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 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 keymap hashtable-print-readable backquote threads dbusbind inotify lcms2 dynamic-setting system-font-setting font-render-setting cairo move-toolbar gtk x-toolkit x multi-tty make-network-process native-compile emacs) Memory information: ((conses 16 990058 38601) (symbols 48 42390 5) (strings 32 194841 12704) (string-bytes 1 6139210) (vectors 16 98218) (vector-slots 8 1847045 66873) (floats 8 689 257) (intervals 56 17287 491) (buffers 992 227)) -- Matthias