Subject: bug#67361: 29.1; MH-E: creating a new folder can sometimes fail with a Lisp error

From: Chris Siebenmann <[email-masked]>
Date: Tue, 21 Nov 2023 20:45:11 -0500

Under some conditions, creating a new (N)MH folder in MH-E can fail with
a Lisp error of 'Wrong type argument: stringp, nil'. This happens if for
some reason you have loaded/required mh-speed.el but have not created a
speedbar.

Reproduction in 'emacs -Q', assuming you have NMH set up:

* enter MH-E with M-x mh-rmail
* widen to your entire inbox so you have something to refile, 'F r'.
* require mh-speed: M-: (require 'mh-soeed)
* select a message and refile with 'o'. When asked for the target
  folder, enter one that doesn't exist, say '+anewtestfolder'. Say y to
  have this folder created.
* the refile will abort with the minibuffer message showing 'Wrong type
  argument: stringp, nil'

The full *Messages* buffer contents are (for my test, with a slightly
different folder path):
	Folder +misc/anewtestfolder does not exist.  Create it? (y or n) y
	Creating +misc/anewtestfolder
	mh-prompt-for-folder: Wrong type argument: stringp, nil

I believe the root cause of this problem is that mh-prompt-for-folder
calls mh-speed-add-folder if 'mh-speed-folder-map is bound:
	(when (boundp 'mh-speed-folder-map)
	  (mh-speed-add-folder folder-name))

However, mh-speed-add-folder requires that speedbar-buffer exists, as it
starts with:
	(with-current-buffer speedbar-buffer
	  ....)

In edebug, it is this with-current-buffer call that appears to fail and
produce the error message when called with no speedbar displayed and
speedbar-buffer nil.

Requiring or loading mh-speed without a speedbuffer displayed is
probably unusual, but I need to do it in order to customize some aspects
of my MH-E speedbar interface.

NOTE: I have reproduced this in 'emacs -Q', but this bug report is filed
from within my regular Emacs and MH-E environment, with multiple third
party packages and load-file shadowing and so on. You can ignore those
parts of this report.

In GNU Emacs 29.1 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.33,
 cairo version 1.16.0) of 2023-10-30 built on comps3
Windowing system distributor 'The X.Org Foundation', version 11.0.12014000
System Description: Ubuntu 22.04.3 LTS

Configured using:
 'configure --prefix /u/cks/lib/x64-linux/emacs-29.1 --without-gsettings
 --with-x --with-x-toolkit=gtk3 --with-json --with-tree-sitter
 --with-native-compilation=aot'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM 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 X11 XDBE XIM XINPUT2 XPM GTK3 ZLIB

Important settings:
  value of $LC_COLLATE: C
  value of $LC_CTYPE: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  smartparens-mode: t
  global-corfu-mode: t
  corfu-mode: t
  marginalia-mode: t
  vertico-mouse-mode: t
  vertico-multiform-mode: t
  vertico-mode: t
  which-key-mode: t
  global-flycheck-mode: t
  flycheck-mode: t
  backward-forward-mode: t
  override-global-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
  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:
/u/cks/.emacs.d/elpa/transient-20231121.1154/transient hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/transient
/u/cks/.emacs.d/elpa/use-package-20230426.2324/use-package-core hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/use-package-core
/u/cks/.emacs.d/elpa/use-package-20230426.2324/use-package-diminish hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/use-package-diminish
/u/cks/.emacs.d/elpa/bind-key-20230203.2004/bind-key hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/bind-key
/u/cks/.emacs.d/elpa/use-package-20230426.2324/use-package-lint hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/use-package-lint
/u/cks/.emacs.d/elpa/use-package-20230426.2324/use-package-jump hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/use-package-jump
/u/cks/.emacs.d/elpa/use-package-20230426.2324/use-package hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/use-package
/u/cks/.emacs.d/elpa/use-package-20230426.2324/use-package-delight hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/use-package-delight
/u/cks/.emacs.d/elpa/use-package-20230426.2324/use-package-bind-key hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/use-package-bind-key
/u/cks/.emacs.d/elpa/use-package-20230426.2324/use-package-ensure hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/use-package/use-package-ensure
/u/cks/.emacs.d/elpa/project-0.10.0/project hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/progmodes/project
/u/cks/.emacs.d/elpa/seq-2.24/seq hides /u/cks/lib/x64-linux/emacs-29.1/share/emacs/29.1/lisp/emacs-lisp/seq

Features:
(shadow mh-identity mh-letter emacsbug orderless project consult
bookmark textsec uni-scripts idna-mapping ucs-normalize uni-confusable
textsec-check shr-color color mule-util qp mm-archive mail-extr mh-seq
mh-inc hl-line mh-tool-bar flyspell ispell mh-xface mh-cks mh-cks-speed
mh-speed speedbar ezimage dframe gnus-icalendar org-capture org-refile
org ob ob-tangle ob-ref ob-lob ob-table ob-exp org-macro org-src
ob-comint org-pcomplete pcomplete comint ansi-osc ring org-list
org-footnote org-faces org-entities noutline outline ob-emacs-lisp
ob-core ob-eval org-cycle org-table ol org-fold org-fold-core org-keys
oc org-loaddefs org-version org-compat org-macs format-spec icalendar
diary-lib diary-loaddefs cal-menu calendar cal-loaddefs mh-utils mh-mime
mh-acros mh-show gnus-cite gnus-art mm-uu mml2015 gnus-sum shr
pixel-fill kinsoku url-file svg dom gnus-group gnus-undo gnus-start
gnus-dbus dbus xml gnus-cloud nnimap nnmail mail-source utf7 nnoo
parse-time iso8601 gnus-spec gnus-int message yank-media dired
dired-loaddefs rfc822 mailabbrev gmm-utils mailheader gnus-win
gnus-range gnus nnheader range wid-edit mh-comp sendmail mail-utils
mh-gnus mml mm-view mml-smime mml-sec epa derived epg rfc6068 epg-config
smime gnutls puny dig mm-decode mm-bodies mm-encode mail-parse rfc2231
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mh-folder which-func imenu
gnus-util text-property-search time-date mh-scan mh-e mh-buffers
mh-loaddefs goto-addr comp comp-cstr warnings icons smartparens advice
loadhist thingatpt .emacs corfu marginalia vertico-mouse
vertico-multiform vertico compat which-key flycheck ansi-color find-func
rx dash backward-forward edmacro kmacro cl-extra help-mode pp diminish
use-package use-package-ensure use-package-delight use-package-diminish
use-package-bind-key bind-key easy-mmode use-package-core finder-inf
company-autoloads consult-flycheck-autoloads consult-flyspell-autoloads
consult-lsp-autoloads corfu-autoloads embark-consult-autoloads
consult-autoloads embark-autoloads evil-autoloads
expand-region-autoloads flycheck-golangci-lint-autoloads
flycheck-autoloads fold-this-autoloads go-mode-autoloads
goto-chg-autoloads lsp-ui-autoloads lsp-mode-autoloads magit-autoloads
pcase git-commit-autoloads magit-section-autoloads marginalia-autoloads
orderless-autoloads project-autoloads markdown-mode-autoloads
f-autoloads rust-mode-autoloads smartparens-autoloads
transient-autoloads try-autoloads vertico-autoloads vundo-autoloads
which-key-autoloads with-editor-autoloads info compat-autoloads
seq-autoloads yaml-mode-autoloads 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 font-render-setting cairo
move-toolbar gtk x-toolkit xinput2 x multi-tty make-network-process
native-compile emacs)

Memory information:
((conses 16 712854 301161)
 (symbols 48 33375 30)
 (strings 32 182335 53947)
 (string-bytes 1 5543861)
 (vectors 16 81476)
 (vector-slots 8 1411017 522310)
 (floats 8 495 1417)
 (intervals 56 4586 1703)
 (buffers 984 24))