GNU bug report logs - #80121
31.0.50; cond*/match* (or ...) patterns

Previous Next

To reply to this bug, email your comments to 80121 AT debbugs.gnu.org.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Richard Lawrence <rwl <at> recursewithless.net>
To: bug-gnu-emacs <at> gnu.org
Subject: 31.0.50; cond*/match* (or ...) patterns 
Date: Sat, 03 Jan 2026 10:41:31 +0100

I am experimenting with `cond*' and `match*' for the first time, and
think I've run into a bug in (or ...) subpatterns.

I have a list of tokens represented like this:

((:date ... :begin ... :end ...)
 (:time ... :begin ... :end ...)
 ...)

I want to match, e.g., the first two items on this list when one is a
date and the other is a time.  So I wrote:

(cond*
 ((match* (cdr-ignore (or (list (list :date d) (list :time t))
                          (list (list :time t) (list :date d))))
          tokens)
  (do-something d t)))

This works as expected: the `list' patterns expand to check that the car
of the inner list is :date or :time, and bind the corresponding
variables.  However, if I also try to match subsequent list elements in
the tokens, like

(cond*
 ((match* (cdr-ignore (or (list (list :date d :begin db)
                                (list :time t :begin tb))
                          (list (list :time t :begin tb)
                                (list :date d :begin db))))
          tokens)
  (do-something d t db tb)))

then this expands to:

(let ((d15675 tokens))
  (let (ba15678 ba15677 ba15676)
    (if (or (progn
              (setq ba15676 nil)
              (setq ba15677 nil)
              (setq ba15678 nil))
            (progn
              (setq ba15678 nil)
              (setq ba15676 nil)
              (setq ba15677 nil)))
        (let* ((d ba15676)
               (db ba15677)
               (tb ba15678))
          (do-something d t db tb))
      nil)))

which simply always returns nil.  I suspect the problem is in the
disjunction pattern handling in `cond*-subpat', where there is a comment
that says:

 ;; The main complexity is unsetting the pattern variables
 ;; that tentatively match in an or-branch that later failed.

The `progn' form which is setting all the bindings to nil is expanded
from `(progn ,@clearing) a little ways below that comment.  It looks to
me like this form is maybe missing a reference to `expression', or
perhaps should be part of a larger form that contains `expression'.  Or
am I misunderstanding something?

Thanks!  Here's the rest of the report-emacs-bug info:

In GNU Emacs 31.0.50 (build 12, x86_64-pc-linux-gnu, GTK+ Version
 3.24.38, cairo version 1.16.0) of 2025-12-22 built on ohm
Repository revision: b185d093e0feab89cdbcebb4a4bf74222144296b
Repository branch: scratch/icalendar
Windowing system distributor 'The X.Org Foundation', version 11.0.12201009
System Description: Debian GNU/Linux 12 (bookworm)

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG
LIBSELINUX LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG SECCOMP SOUND
SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP X11 XDBE XIM XINERAMA
XINPUT2 XPM XRANDR GTK3 ZLIB

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

Major mode: Lisp Interaction

Minor modes in effect:
  recentf-mode: t
  global-git-commit-mode: t
  magit-auto-revert-mode: t
  server-mode: t
  override-global-mode: t
  global-evil-surround-mode: t
  evil-surround-mode: t
  evil-mode: t
  evil-local-mode: t
  ivy-mode: t
  electric-pair-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  minibuffer-nonselected-mode: t
  minibuffer-regexp-mode: t
  line-number-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
/home/rwl/.emacs.d/elpa/magit-4.1.0/magit-autorevert hides /home/rwl/.emacs.d/elpa/magit-section-4.1.0/magit-autorevert
/home/rwl/.emacs.d/elpa/lua-mode-20231023.947/lua-mode hides /home/rwl/src/emacs/lisp/progmodes/lua-mode

Features:
(shadow emacsbug lisp-mnt smiley gnus-cite gnus-async gnus-bcklg
gnus-agent gnus-srvr gnus-score score-mode nnvirtual nntp gnus-ml
gnus-msg nndoc gnus-cache gnus-dup display-line-numbers debbugs-gnu
debbugs soap-client rng-xsd xsd-regexp debbugs-compat woman man pulse
descr-text propose-time calc-undo calc-misc whitespace network-stream
url-cache cond-star help-macro elfeed-link elfeed-show elfeed-search
elfeed-csv elfeed elfeed-curl elfeed-log xml-query elfeed-db elfeed-lib
gnus-icalendar-tests gnus-icalendar org-capture epa-file calc-alg
em-unix em-term term disp-table ehelp em-script em-prompt em-pred em-ls
em-hist em-glob em-extpipe em-cmpl em-dirs em-basic em-banner em-alias
esh-mode esh-var calc-arith calc-map calc-stat calc-vec calc-ext
calc-menu calc-aent calc calc-loaddefs calc-macs tex-mode cal-julian
lunar solar let-alist cc-mode cc-fonts cc-guess cc-menus cc-cmds
cc-styles cc-align cc-engine cc-vars cc-defs textsec uni-scripts
idna-mapping ucs-normalize uni-confusable textsec-check qp sort flyspell
orgalist magit-patch cus-edit cus-load texinfo texinfo-loaddefs ert-x
novice thai-util thai-word git-rebase icalendar-mode ol-eww eww vtable
url-queue mm-url ol-rmail ol-mhe ol-irc ol-info ol-gnus nnselect
gnus-art mm-uu mml2015 gnus-sum shr pixel-fill kinsoku url-file svg dom
gnus-group gnus-undo gnus-start gnus-dbus dbus gnus-cloud nnimap nnmail
mail-source utf7 nnoo gnus-spec gnus-int gnus-range gnus-win gnus
nnheader range ol-docview doc-view jka-compr image-mode exif ol-bibtex
bibtex ol-bbdb ol-w3m ol-doi org-link-doi tabify cal-move ledger-mode
ledger-check ledger-texi ledger-test ledger-sort ledger-report
ledger-reconcile ledger-occur ledger-fonts ledger-fontify ledger-state
ledger-complete ledger-schedule ledger-xact ledger-post ledger-exec
ledger-init ledger-navigate eshell esh-cmd esh-ext esh-proc esh-opt
esh-io esh-arg esh-module esh-module-loaddefs esh-util ledger-context
ledger-commodities ledger-regex cua-base cl-print copyright mm-archive
grep mule-util ert ewoc debug backtrace mail-extr dired-aux vc
magit-extras face-remap recentf tree-widget magit-bookmark bookmark
icalendar-macs tramp-sh shortdoc comp-common help-fns radix-tree
misearch multi-isearch vc-git vc-dispatcher bug-reference ffap
tramp-cache time-stamp tramp trampver tramp-integration files-x
tramp-message tramp-compat tramp-loaddefs warnings ediff ediff-merg
ediff-mult ediff-wind ediff-diff ediff-help ediff-init ediff-util
magit-submodule 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 imenu magit-diff
smerge-mode diff git-commit log-edit pcvs-util add-log magit-core
magit-autorevert autorevert filenotify magit-margin magit-transient
magit-process with-editor server magit-mode transient benchmark
magit-git magit-base magit-section cursor-sensor dash two-column ob-R
ob-python python ob-shell shell org-caldav url-dav parse-time iso8601
url-http url-auth url-gw nsm xml ox-odt rng-loc rng-uri rng-parse
rng-match rng-dt rng-util rng-pttrn nxml-parse nxml-ns nxml-enc xmltok
nxml-util ox-latex ox-icalendar ox-html table ox-ascii ox-publish ox
org-attach org-agenda org-element org-persist org-id avl-tree generator
org-refile ol-notmuch notmuch notmuch-tree notmuch-jump notmuch-hello
wid-edit notmuch-show notmuch-print notmuch-crypto notmuch-mua
notmuch-message notmuch-draft notmuch-maildir-fcc notmuch-address
notmuch-company notmuch-parser notmuch-wash diff-mode track-changes
coolj goto-addr notmuch-tag crm notmuch-lib notmuch-compat hl-line
message sendmail yank-media rfc822 mml mailabbrev mail-utils gmm-utils
mailheader mm-view mml-smime mml-sec gnus-util smime gnutls puny dig
mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 mm-util
ietf-drums mail-prsvr compat org ob ob-tangle ob-ref ob-lob ob-table
ob-exp org-macro org-src sh-script smie treesit executable ob-comint
org-pcomplete pcomplete org-list org-footnote org-faces org-entities
noutline outline org-version ob-emacs-lisp ob-core ob-eval org-cycle
org-table ol org-fold org-fold-core org-keys oc org-loaddefs find-func
org-compat use-package-bind-key bind-key easy-mmode evil-surround evil
evil-keybindings evil-integration evil-maps evil-commands reveal
evil-jumps evil-command-window evil-types evil-search evil-ex
evil-macros evil-repeat evil-states evil-core evil-common thingatpt rect
evil-vars edmacro kmacro diary-icalendar pp cal-dst icalendar-recur
icalendar-utils icalendar-parser time-date icalendar-ast org-element-ast
inline org-macs format-spec icalendar diary-lib diary-loaddefs skeleton
cal-menu calendar cal-loaddefs epa derived epg rfc6068 epg-config advice
counsel xref project dired dired-loaddefs compile text-property-search
comint ansi-osc ansi-color swiper ivy delsel ring ivy-faces ivy-overlay
colir elec-pair ispell rx solarized-dark-theme solarized-theme solarized
solarized-faces color cl-extra help-mode use-package-ensure
use-package-core finder-inf calfw-autoloads calfw-ical-autoloads
counsel-autoloads debbugs-autoloads elfeed-autoloads
evil-surround-autoloads evil-autoloads gnu-elpa-keyring-update-autoloads
goto-chg-autoloads howm-autoloads ledger-mode-autoloads
lua-mode-autoloads magit-autoloads pcase magit-section-autoloads
dash-autoloads markdown-mode-autoloads ol-notmuch-autoloads
notmuch-autoloads org-caldav-autoloads solarized-theme-autoloads
swiper-autoloads ivy-autoloads info with-editor-autoloads xr-autoloads
yaml-mode-autoloads package browse-url xdg 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 icons 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
touch-screen 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 x-toolkit xinput2 x multi-tty move-toolbar
make-network-process tty-child-frames emacs)

Memory information:
((conses 16 2456394 674674) (symbols 48 64136 2)
 (strings 32 265404 32661) (string-bytes 1 65454423)
 (vectors 16 173126) (vector-slots 8 2444619 307649)
 (floats 8 1449 3766) (intervals 56 146348 12559) (buffers 984 139))

Message #8 received at 80121 <at> debbugs.gnu.org (full text, mbox):

From: Richard Lawrence <rwl <at> recursewithless.net>
To: 80121 <at> debbugs.gnu.org
Subject: Re: bug#80121: 31.0.50; cond*/match* (or ...) patterns 
Date: Sat, 03 Jan 2026 17:22:20 +0100

[Message part 1 (text/plain, inline)]

rwl <at> recursewithless.net writes:

> The `progn' form which is setting all the bindings to nil is expanded
> from `(progn ,@clearing) a little ways below that comment.  It looks
> to me like this form is maybe missing a reference to `expression', or
> perhaps should be part of a larger form that contains `expression'.

Indeed, the attached patch appears to fix the issue.  But I'm not very
familiar with this code, so please verify that it's the right fix.

-- 
Best,
Richard

[0001-Fix-or-.-patterns-in-match.patch (text/x-diff, attachment)]

Message #11 received at 80121 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Richard Lawrence <rwl <at> recursewithless.net>, Richard Stallman <rms <at> gnu.org>
Cc: 80121 <at> debbugs.gnu.org
Subject: Re: bug#80121: 31.0.50; cond*/match* (or ...) patterns
Date: Sun, 04 Jan 2026 11:30:18 +0200

> From: Richard Lawrence <rwl <at> recursewithless.net>
> Date: Sat, 03 Jan 2026 17:22:20 +0100
> 
> rwl <at> recursewithless.net writes:
> 
> > The `progn' form which is setting all the bindings to nil is expanded
> > from `(progn ,@clearing) a little ways below that comment.  It looks
> > to me like this form is maybe missing a reference to `expression', or
> > perhaps should be part of a larger form that contains `expression'.
> 
> Indeed, the attached patch appears to fix the issue.  But I'm not very
> familiar with this code, so please verify that it's the right fix.

Thanks, I've added Richard Stallman, who wrote that code, to this
discussion.  Richard, any comments to the patch?

> >From f593b96bca6acb7ff8fad8ef2cd9b69a84900cc5 Mon Sep 17 00:00:00 2001
> From: Richard Lawrence <rwl <at> recursewithless.net>
> Date: Sat, 3 Jan 2026 17:10:54 +0100
> Subject: [PATCH] Fix (or ...) patterns in match*
> 
> This is a draft fix for Bug#80121.
> 
> * lisp/emacs-lisp/cond-star.el (cond*-subpat): Add missing reference to
> 'expression' when clearing multiple backtrack aliases.
> ---
>  lisp/emacs-lisp/cond-star.el | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lisp/emacs-lisp/cond-star.el b/lisp/emacs-lisp/cond-star.el
> index fc8e261339e..26cd858600c 100644
> --- a/lisp/emacs-lisp/cond-star.el
> +++ b/lisp/emacs-lisp/cond-star.el
> @@ -706,7 +706,7 @@ cond*-subpat
>                             (if (null (cdr clearing))
>                                 `(or ,expression
>                                      ,(car clearing))
> -                             `(progn ,@clearing))))))
> +                             `(or ,expression (progn ,@clearing)))))))
>                 (push expression expressions)))
>             ;; At end of (or...), EACH variable bound by any arm
>             ;; has a backtrack alias gensym.  At run time, that gensym's value
> -- 
> 2.39.5
> 

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.