bug#64839: 29.0.91; error when try to use M-r to search history

[Drew Adams]

emacs -Q

C-h v
M-n
M-n
M-r
e RET

That raises this error (and unfortunately shows it with
`minibuffer-message', so it disappears quickly):

 funcall-interactively: Wrong type argument: stringp, nil

(Same thing, if I delete the variable inserted from `M-n' before using
`M-r'.)

Not only that, but I see, in *Messages*, zillions of messages such as
this (for different files):

 Checking 89 files in
d:/Emacs-29.0.91_1-2023-05-16/share/emacs/29.0.91/lisp/international...

Dunno what that's about.

When I try the same thing again, I sometimes see this message:

 error when try to use M-r to search history

That's just text that appears in the minibuffer, as if it were input to
be entered at the prompt of `describe-variable'.  Apparently it's not
from `message', and it's not from `minibuffer-message'.

Crazy behavior.
___

I see the same error message ("Wrong type argument: stringp, nil") as
far back as Emacs 23.4).  But I don't see those "Checking files..."
message in *Messages* before Emacs 29 (pretest).  There's no error in
Emacs 22.3, but there there's no automatic filling of "future history",
so `M-n' just says "End of history; no default available".


In GNU Emacs 29.0.91 (build 2, x86_64-w64-mingw32) of 2023-05-14 built
 on AVALON
Windowing system distributor 'Microsoft Corp.', version 10.0.19045
System Description: Microsoft Windows 10 Pro (v10.0.2009.19045.3086)

Configured using:
 'configure --with-modules --without-dbus --with-native-compilation
 --without-compress-install --with-tree-sitter CFLAGS=-O2'

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

(NATIVE_COMP present but libgccjit not available)

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252

Major mode: Minibuffer

Minor modes in effect:
  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
  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 message mailcap yank-media puny rfc822
mml mml-sec password-cache epa derived epg rfc6068 epg-config gnus-util
text-property-search time-date subr-x mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils thingatpt help-fns
radix-tree help-mode dired-aux cl-loaddefs cl-lib dired dired-loaddefs
rmc iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel dos-w32 ls-lisp disp-table
term/w32-win w32-win w32-vars 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 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 w32notify w32 lcms2 multi-tty
make-network-process native-compile emacs)

Memory information:
((conses 16 51837 13411)
 (symbols 48 5795 0)
 (strings 32 18933 2147)
 (string-bytes 1 471851)
 (vectors 16 11110)
 (vector-slots 8 223353 11950)
 (floats 8 37 30)
 (intervals 56 231 10)
 (buffers 984 11))