From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier via Users list for the GNU Emacs text editor Newsgroups: gmane.emacs.help Subject: Re: How to debug erratic specializer behavior of generic functions Date: Sun, 20 Feb 2022 18:56:40 -0500 Message-ID: References: <871qzx2jrt.fsf@web.de> Reply-To: Stefan Monnier Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="30138"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:iKJyq4/sNASgn/zKQvG+mD8tD2w= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon Feb 21 00:57:26 2022 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nLw50-0007jY-Bg for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 21 Feb 2022 00:57:26 +0100 Original-Received: from localhost ([::1]:47934 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nLw4y-0001iN-Tz for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 20 Feb 2022 18:57:24 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:54096) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nLw4U-0001iB-NT for help-gnu-emacs@gnu.org; Sun, 20 Feb 2022 18:56:54 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]:60118) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nLw4S-0004dY-Hv for help-gnu-emacs@gnu.org; Sun, 20 Feb 2022 18:56:54 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1nLw4L-0006yh-JH for help-gnu-emacs@gnu.org; Mon, 21 Feb 2022 00:56:45 +0100 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:136088 Archived-At: > Any hints for where to dig, how to debug, or what could be involved? So > far I have nothing for emacs -Q, no recipe, that demonstrates the > behavior (that's why I chose to ask here first before starting a bug > report). If you're seeing this with Emacs's code on `master`, then please report it as a bug. If you're seeing it with Emacs < 29, then I suggest you try the patch below. Stefan diff --git a/lisp/emacs-lisp/cl-generic.el b/lisp/emacs-lisp/cl-generic.el index 983694204df..5090e060372 100644 --- a/lisp/emacs-lisp/cl-generic.el +++ b/lisp/emacs-lisp/cl-generic.el @@ -604,7 +604,9 @@ cl--generic-dispatchers (defun cl--generic-get-dispatcher (dispatch) (with-memoization - (gethash dispatch cl--generic-dispatchers) + ;; We need `copy-sequence` here because this `dispatch' object might be + ;; modified by side-effect in `cl-generic-define-method' (bug#46722). + (gethash (copy-sequence dispatch) cl--generic-dispatchers) ;; (message "cl--generic-get-dispatcher (%S)" dispatch) (let* ((dispatch-arg (car dispatch)) (generalizers (cdr dispatch))