bug#55213: 29.0.50; define-minor-mode/easy-mmode--mode-docstring doesn't handle empty DOC ("")

[Taku Tekato]

easy-mmode--mode-docstring now calls `string-lines` on DOC and processes
by poping lines from the result.

Therefore the error `(wrong-type-argument char-or-string-p nil)` breaks
various packages who define minor modes with empty docstrings.



In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.33, cairo 
version 1.17.6)
of 2022-05-01 built on c18
Repository revision: 7c8bec9e1ffe087918f6f218fc4560fc968aebb2
Repository branch: master
System Description: Arch Linux

Configured using:
'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
--localstatedir=/var --mandir=/usr/share/man --with-gameuser=:games
--with-sound=alsa --with-modules --without-libotf --without-m17n-flt
--without-gconf --without-gsettings --with-native-compilation
--with-xinput2 --with-pgtk --without-xaw3d --with-sound=alsa
--with-xwidgets --without-compress-install
'--program-transform-name=s/\([ec]tags\)/\1.emacs/'
'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions
-Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security
-fstack-clash-protection -fcf-protection'
LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM HARFBUZZ JPEG JSON LCMS2
LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PGTK PNG
RSVG SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP XIM
XWIDGETS GTK3 ZLIB

Important settings:
value of $LC_CTYPE: en_GB.UTF-8
value of $LANG: en_US.UTF-8
value of $XMODIFIERS: @im=fcitx
locale-coding-system: utf-8-unix

Major mode: Outline

Minor modes in effect:
global-evil-surround-mode: t
evil-surround-mode: t
eros-mode: t
dap-tooltip-mode: t
dap-ui-controls-mode: t
dap-ui-mode: t
flyspell-lazy-mode: t
whitespace-mode: t
vi-tilde-fringe-mode: t
display-line-numbers-mode: t
highlight-indent-guides-mode: t
adaptive-wrap-prefix-mode: t
+word-wrap-mode: t
global-anzu-mode: t
anzu-mode: t
pixel-scroll-precision-mode: t
diff-hl-margin-mode: t
dired-async-mode: t
git-gutter-mode: t
treemacs-project-follow-mode: t
global-tree-sitter-mode: t
global-blamer-mode: t
my-auto-sidebar-mode: t
treemacs-filewatch-mode: t
treemacs-follow-mode: t
treemacs-git-mode: t
treemacs-fringe-indicator-mode: t
gdb-many-windows: t
dap-mode: t
projectile-mode: t
minibuffer-depth-indicate-mode: t
solaire-global-mode: t
corfu-doc-mode: t
corfu-indexed-mode: t
global-corfu-mode: t
corfu-mode: t
bug-reference-mode: t
yas-global-mode: t
yas-minor-mode: t
dtrt-indent-mode: t
which-key-mode: t
savehist-mode: t
better-jumper-mode: t
better-jumper-local-mode: t
vertico-mouse-mode: t
vertico-mode: t
all-the-icons-completion-mode: t
marginalia-mode: t
evil-goggles-mode: t
evil-snipe-override-mode: t
evil-snipe-mode: t
evil-snipe-override-local-mode: t
evil-snipe-local-mode: t
recentf-mode: t
save-place-mode: t
global-so-long-mode: t
global-git-commit-mode: t
text-scale-mode: t
gcmh-mode: t
global-hl-line-mode: t
hl-line-mode: t
winner-mode: t
smartparens-global-mode: t
smartparens-mode: t
ws-butler-global-mode: t
ws-butler-mode: t
global-undo-fu-session-mode: t
undo-fu-session-mode: t
undo-fu-mode: t
global-flycheck-mode: t
flycheck-mode: t
doom-modeline-mode: t
nyan-mode: t
minions-mode: t
global-subword-mode: t
subword-mode: t
cua-mode: t
key-chord-mode: t
shell-dirtrack-mode: t
evil-mode: t
evil-local-mode: t
windmove-mode: t
+popup-mode: t
override-global-mode: t
my-puni-global-mode: t
general-override-mode: t
puni-mode: t
my-outline-comment-global-mode: t
my-global-auto-format-mode: t
my-auto-format-mode: t
my-minibuffer-input-history-mode: t
global-eldoc-mode: t
show-paren-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
file-name-shadow-mode: t
context-menu-mode: t
global-font-lock-mode: t
font-lock-mode: t
window-divider-mode: t
undelete-frame-mode: t
size-indication-mode: t
column-number-mode: t
line-number-mode: t
visual-line-mode: t
transient-mark-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t

Features:
(shadow sort mail-extr emacsbug mm-archive url-cache define-word
nxml-mode-expansions rng-nxml rng-valid rng-loc rng-uri rng-parse
nxml-parse rng-match rng-dt rng-util rng-pttrn nxml-ns nxml-mode
nxml-outln nxml-rap html-mode-expansions smartparens-html sgml-mode
facemenu nxml-util nxml-enc xmltok elisp-def ert elisp-demos
evil-collection-indent magit-extras overseer pkg-info epl
my-emacs-utilities my-shell-functions evil-collection-help flycheck-cask
evil-embrace evil-surround eros lispyville lispy hydra lispy-inline
etags fileloop lispy-tags mode-local highlight-quoted rainbow-delimiters
my-sticky-header my-outline-comment-mode hideshow lsp lsp-dart
lsp-dart-commands lsp-dart-flutter-widget-guide
lsp-dart-flutter-fringe-colors lsp-dart-flutter-colors lsp-dart-outline
lsp-dart-code-lens lsp-dart-test-tree lsp-dart-test-output
lsp-dart-test-support lsp-dart-dap lsp-dart-devtools
lsp-dart-flutter-daemon lsp-dart-closing-labels lsp-dart-utils
lsp-dart-protocol lsp-haskell lsp-pyright dap-gdb-lldb dap-utils
dap-lldb ccls ccls-member-hierarchy ccls-inheritance-hierarchy
ccls-call-hierarchy ccls-tree ccls-code-lens ccls-semantic-highlight
ccls-common cc-mode-expansions smartparens-c cc-mode cc-fonts cc-guess
cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs dap-mouse
dap-ui lsp-treemacs lsp-treemacs-themes treemacs-magit
treemacs-all-the-icons treemacs-projectile treemacs-evil treemacs
treemacs-header-line treemacs-compatibility treemacs-mode
treemacs-bookmarks treemacs-interface treemacs-extensions
treemacs-mouse-interface treemacs-tags treemacs-persistence
treemacs-filewatch-mode treemacs-faces treemacs-macros gdb-mi bindat gud
bui bui-list bui-info bui-entry bui-core bui-history bui-button
bui-utils lsp-lens dap-mode dap-launch posframe dap-overlays lsp-mode
org-crypt evil-collection-view view org-eldoc embrace expand-region
subword-mode-expansions text-mode-expansions the-org-mode-expansions
er-basic-expansions expand-region-core expand-region-custom toc-org
evil-org writegood-mode org-indent image-file image-converter oc-basic
ol-bibtex bibtex my-goto-outline evil-collection-helpful helpful trace
evil-collection-edebug edebug evil-collection-debug debug info-look
evil-collection-info info evil-collection-elisp-refs elisp-refs dabbrev
hippie-exp cape-keyword cape highlight-numbers parent-mode flyspell-lazy
ispell flyspell conf-mode evil-collection-macrostep macrostep
consult-xref embark-consult evil-collection-embark embark ffap goto-addr
evil-collection-tabulated-list epkg-melpa epkg-gelpa epkg-utils
epkg-list epkg-desc epkg compat-26 whitespace vi-tilde-fringe
display-line-numbers highlight-indent-guides adaptive-wrap tramp-archive
tramp-gvfs tramp-cache zeroconf dbus magit-gitflow magit-delta
xterm-color tabify evil-collection-evil-mc evil-mc
evil-mc-command-execute evil-mc-command-record evil-mc-cursor-make
evil-mc-region evil-mc-cursor-state evil-mc-undo evil-mc-vars
evil-mc-known-commands evil-mc-common jka-compr apheleia
my-version-control-functions my-format evil-anzu anzu char-fold swiper
evil-collection-ivy ivy ivy-faces ivy-overlay colir
evil-collection-sh-script sh-script smie executable my-compiled-commands
pixel-scroll hide-mode-line my-dired-functions diredfl diff-hl-margin
diff-hl-dired evil-collection-diff-hl diff-hl evil-collection-log-view
log-view evil-collection-vc-dir vc-dir all-the-icons-dired dired-async
my-project-file-functions my-dired-count mwim my-commands puni
my-config-evil vertico-directory ace-window avy my-other-window vc-hg
vc-svn vc auto-minor-mode consult-flycheck evil-collection-consult
consult-vertico consult mule-util git-gutter-fringe fringe-helper
git-gutter evil-collection-vc-git vc-git vc-dispatcher
treemacs-project-follow-mode treemacs-follow-mode treemacs-rendering
treemacs-async treemacs-visuals treemacs-fringe-indicator
treemacs-workspaces treemacs-dom treemacs-icons treemacs-themes
treemacs-scope treemacs-core-utils treemacs-logging
treemacs-customization pfuture tree-sitter-langs tree-sitter-langs-build
tree-sitter-hl help-fns radix-tree cl-print backtrace tree-sitter
tree-sitter-load tree-sitter-cli tsc tsc-dyn tsc-dyn-get dired-aux
tsc-obsolete blamer lsp-protocol evil-collection-xref xref project
spinner network-stream lv inline ewoc my-config-minibuffer
my-completion-style cursor-sensor vertico-repeat projectile ibuf-ext
evil-collection-ibuffer ibuffer ibuffer-loaddefs mb-depth
doom-themes-ext-treemacs doom-themes-ext-org solaire-mode
doom-dracula-theme doom-themes doom-themes-base corfu-doc kind-icon
svg-lib corfu-indexed corfu desktop frameset org-capture org-agenda
evil-collection-magit-todos magit-todos pcre2el rxt re-builder hl-todo
async evil-collection-grep grep evil-collection-org smartparens-org
org-yt org-element org-persist xdg org-id org-refile avl-tree org ob
ob-tangle ob-ref ob-lob ob-table ob-exp org-macro org-footnote org-src
ob-comint org-pcomplete org-list org-faces org-entities org-version
ob-emacs-lisp ob-core ob-eval org-table ol org-keys oc org-compat
org-macs org-loaddefs evil-collection-calendar cal-menu calendar
cal-loaddefs code-review code-review-actions code-review-comment
code-review-section code-review-bitbucket code-review-faces shr
pixel-fill kinsoku url-file url-dired svg xml dom emojify
evil-collection-apropos apropos evil-collection-tar-mode tar-mode
evil-collection-arc-mode arc-mode archive-mode ht code-review-gitlab
code-review-utils evil-collection-forge forge-list forge-commands
forge-semi forge-bitbucket buck forge-gogs gogs forge-gitea gtea
forge-gitlab glab forge-github forge-notify forge-revnote forge-pullreq
forge-issue forge-topic yaml bug-reference forge-post
smartparens-markdown evil-collection-markdown-mode markdown-mode
edit-indirect noutline outline forge-repo forge forge-core forge-db
code-review-parse-hunk code-review-github code-review-db uuidgen
calc-misc calc-ext a code-review-interfaces deferred ghub-graphql treepy
gsexp ghub gnutls closql emacsql-sqlite emacsql emacsql-compiler
url-http url-auth url-gw nsm evil-collection-magit magit-bookmark
magit-autoloads magit-submodule magit-obsolete magit-popup magit-blame
magit-stash magit-reflog magit-bisect magit-push magit-pull magit-fetch
magit-clone magit-remote magit-commit magit-sequence magit-notes
magit-worktree magit-tag magit-merge magit-branch magit-reset
magit-files magit-refs magit-status magit magit-repos magit-apply
magit-wip magit-log which-func magit-diff smerge-mode diff
evil-collection-diff-mode diff-mode magit-core magit-autorevert
autorevert filenotify magit-margin magit-transient magit-process
yasnippet-snippets doom-snippets doom-snippets-lib yasnippet
evil-collection-elisp-mode elisp-mode dtrt-indent
evil-collection-which-key which-key savehist better-jumper vertico-mouse
evil-collection-vertico vertico orderless all-the-icons-completion
marginalia evil-goggles pulse evil-easymotion evil-snipe recentf
tree-widget saveplace so-long git-commit with-editor
evil-collection-vterm vterm evil-collection-bookmark bookmark tramp
tramp-loaddefs trampver tramp-integration cus-start files-x tramp-compat
parse-time iso8601 ls-lisp face-remap evil-collection-compile compile
color vterm-module term/xterm xterm evil-collection-term term disp-table
ehelp esh-help evil-collection-man man em-unix eshell-z em-dirs esh-var
evil-collection-eshell em-prompt eshell-did-you-mean esh-mode eshell
esh-cmd generator esh-ext esh-opt esh-proc esh-io esh-arg esh-module
esh-groups esh-util server evil-collection-log-edit log-edit message
sendmail yank-media rmc puny evil-collection-dired dired dired-loaddefs
rfc822 mml mml-sec evil-collection-epa epa epg rfc6068 epg-config
gnus-util text-property-search time-date mm-decode mm-bodies mm-encode
mail-parse rfc2231 rfc2047 rfc2045 mm-util ietf-drums mail-prsvr
mailabbrev mail-utils gmm-utils mailheader pcvs-util add-log magit-mode
transient magit-git magit-base magit-section format-spec crm gcmh
hl-line winner smartparens-config smartparens-text smartparens ws-butler
undo-fu-session undo-fu flycheck-package package-lint
evil-collection-imenu imenu evil-collection-finder finder finder-inf
lisp-mnt evil-collection-package-menu core-packages 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 eieio
eieio-core eieio-loaddefs password-cache url-vars
evil-collection-flycheck evil-collection-custom evil-collection-comint
evil-collection annalist flycheck json map find-func doom-modeline
doom-modeline-segments doom-modeline-env doom-modeline-core shrink-path
all-the-icons all-the-icons-faces data-material data-weathericons
data-octicons data-fileicons data-faicons data-alltheicons my-custom
my-config nyan-mode minions compat cap-words superword subword
two-column cus-edit cus-load wid-edit delsel cua-base key-chord
smartparens-lua smartparens-elixir let-alist evil evil-integration
evil-maps evil-commands reveal evil-jumps evil-command-window
evil-search shell pcomplete comint ansi-color evil-types evil-macros
evil-repeat evil-states evil-core advice evil-common windmove calc
calc-loaddefs calc-macs thingatpt rect evil-digraphs evil-vars ring
edmacro kmacro derived use-package-bind-key bind-key my-config-functions
my-init my-core-functions 00-my-core-macros f s dash my-lib-man
my-early-init core-editor core-projects core-ui easy-mmode core-keybinds
pp general use-package-core core-modules realgud-recursive-autoloads
core comp comp-cstr warnings rx cl-seq cl-extra help-mode seq subr-x
byte-opt bytecomp byte-compile cconv core-lib pcase cl-macs gv
cl-loaddefs cl-lib chemacs iso-transl tooltip eldoc paren electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel term/pgtk-win
pgtk-win term/common-win 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 simple 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 abbrev obarray oclosure cl-preloaded 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 xwidget-internal dbusbind
inotify dynamic-setting font-render-setting cairo gtk pgtk lcms2
multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 2786955 456492)
(symbols 48 101734 1)
(strings 32 553345 55247)
(string-bytes 1 14325932)
(vectors 16 212292)
(vector-slots 8 5229181 233117)
(floats 8 18440 3051)
(intervals 56 136690 51300)
(buffers 992 51))