Subject: 29.0.92; M-s and M-r don't search in "future history"

From: Eli Zaretskii <[email-masked]>
Date: Sat, 22 Jul 2023 11:23:15 +0300

To reproduce:

  emacs -Q
  C-h v
  M-n

Observe that a variable's name is inserted into the minibuffer; in my
case it's "find-sibling-rules".  (It was inserted by
minibuffer-default-add-completions.)

  M-p

Now the minibuffer is empty (except for the prompt), and
find-sibling-rules is in "future history".

  M-s sibling RET

Surprise: instead of finding find-sibling-rules, this displays a
message: "No later matching history element".

  M-n
  M-n

Now we have 2 elements in the "future history", but:

  M-r sibling RET

signals an error: Wrong type argument: stringp, nil, instead of
finding find-sibling-rules.

Bottom line: M-n and M-p unexpectedly don't search "future history".
Without that, adding all of the completion candidates to "future
history" is a misfeature when the list of candidates is very long.

In GNU Emacs 29.0.92 (build 50, i686-pc-mingw32) of 2023-07-22 built on
 HOME-C4E4A596F7
Repository revision: 101455cb8534d07518871c0287e4861e09f22a32
Repository branch: emacs-29
Windowing system distributor 'Microsoft Corp.', version 5.1.2600
System Description: Microsoft Windows XP Service Pack 3 (v5.1.0.2600)

Configured using:
 'configure -C --prefix=/d/usr --with-wide-int
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -gdwarf-4 -g3''

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

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  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
  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 dired
dired-loaddefs 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 cl-loaddefs cl-lib 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 emacs)

Memory information:
((conses 16 50421 10650)
 (symbols 48 6535 0)
 (strings 16 19656 2646)
 (string-bytes 1 444218)
 (vectors 16 9854)
 (vector-slots 8 152370 10526)
 (floats 8 27 34)
 (intervals 40 276 68)
 (buffers 888 12))