Subject: bug#79059: 31.0.50; eshell-emit-prompt errors when front-sticky or rear-nonsticky properties are set to t

From: László Vaskó <[email-masked]>
Date: Sun, 20 Jul 2025 12:00:55 +0200

Hello,

Since df288d2e414 (bug#74230) eshell is more careful adding text
properties to prompts using `eshell--append-text-property'. It's
implementation assumes that `get-text-property' will always return a
list. This is not true, as both `front-sticky' and `rear-nonsticky'
properties can be set to t.

Repro:

-- 8< --
cat <<EOF > /tmp/init-eshell-propertized-prompt.el
;; -*- lexical-binding: t; -*-
(setq eshell-prompt-function 
      (defun propertizing-prompt ()
        (setq eshell-prompt-string (propertize "test" 'rear-nonsticky t))))
(eshell)                           
EOF                                                    
emacs -Q --batch --load /tmp/init-eshell-propertized-prompt.el
-- 8< --

Output:

    Loading eshell-alias...
    Loading eshell-alias...done
    Loading eshell-banner...
    Loading eshell-banner...done
    Loading eshell-basic...
    Loading eshell-basic...done
    Loading eshell-cmpl...
    Loading eshell-cmpl...done
    Loading eshell-extpipe...
    Loading eshell-extpipe...done
    Loading eshell-glob...
    Loading eshell-glob...done
    Loading eshell-hist...
    Loading eshell-hist...done
    Loading eshell-ls...
    Loading eshell-ls...done
    Loading eshell-pred...
    Loading eshell-pred...done
    Loading eshell-prompt...
    Loading eshell-prompt...done
    Loading eshell-script...
    Loading eshell-script...done
    Loading eshell-term...
    Loading eshell-term...done
    Loading eshell-unix...
    Loading eshell-unix...done

    Error: wrong-type-argument (sequencep t)
      eshell--append-text-property(0 4 rear-nonsticky (read-only font-lock-face field) #("test" 0 4 (front-sticky (read-only font-lock-face field) font-lock-face eshell-prompt read-only t field prompt rear-nonsticky t)))
      eshell-emit-prompt()
      run-hooks(eshell-post-command-hook)
      eshell-mode()
      eshell()
      load-with-code-conversion("/tmp/init-eshell-propertized-prompt.el" "/tmp/init-eshell-propertized-prompt.el" nil t)
      command-line-1(("--load" "/tmp/init-eshell-propertized-prompt.el"))
      command-line()
      normal-top-level()

    debug-early-backtrace...done
    Wrong type argument: sequencep, t

In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
3.24.49, cairo version 1.18.4)
Repository revision: 382123e69e2c0cae39e44f9b72ca3674eaec2ad1
Repository branch: master
System Description: NixOS 25.11 (Xantusia)

Configured using:
'configure
--prefix=/nix/store/463a7h9nwlk9yzni8s1cb7dhvi8k2dd0-emacs-igc-pgtk-20250716.0
--disable-build-details --with-modules --with-pgtk
--with-compress-install --with-toolkit-scroll-bars
--with-native-compilation --without-imagemagick --with-mailutils
--without-small-ja-dic --with-tree-sitter --without-xinput2
--without-xwidgets --with-dbus --with-selinux --with-mps=yes'

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
LIBSELINUX LIBSYSTEMD LIBXML2 MODULES MPS NATIVE_COMP NOTIFY INOTIFY
PDUMPER PGTK PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XIM GTK3 ZLIB

Important settings:
  value of $LANG: hu_HU.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Eshell

Minor modes in effect:
  eshell-prompt-mode: t
  eshell-pred-mode: t
  eshell-hist-mode: t
  eshell-cmpl-mode: t
  eshell-proc-mode: t
  eshell-arg-mode: t
  tooltip-mode: t
  global-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
  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 lisp-mnt message mailcap yank-media puny
dired dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg
rfc6068 epg-config gnus-util 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 compile comp-run
comp-common em-unix em-term term disp-table shell ehelp em-script
em-prompt text-property-search em-pred em-ls em-hist em-glob rx
em-extpipe em-cmpl em-dirs em-basic em-banner em-alias esh-mode esh-var
eshell esh-cmd generator cl-loaddefs cl-lib esh-ext esh-proc esh-opt
esh-io byte-opt gv bytecomp byte-compile esh-arg pcomplete comint subr-x
ansi-osc ansi-color ring esh-module esh-module-loaddefs esh-util files-x
rmc iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel term/pgtk-win pgtk-win
term/common-win touch-screen pgtk-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
dynamic-setting system-font-setting font-render-setting cairo gtk pgtk
multi-tty move-toolbar make-network-process tty-child-frames
native-compile mps emacs)

Memory information:
((conses 24 0 0) (symbols 56 0 0) (strings 40 0 0) (string-bytes 1 0)
(vectors 24 0) (vector-slots 8 0 0) (floats 24 0 0)
(intervals 64 0 0) (buffers 1072 0))

--

László Vaskó