From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: "The starting list count" ????? Date: Mon, 3 Jan 2022 21:33:01 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="18141"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Jan 03 22:33:54 2022 Return-path: Envelope-to: ged-emacs-devel@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 1n4Uxi-0004PV-BQ for ged-emacs-devel@m.gmane-mx.org; Mon, 03 Jan 2022 22:33:50 +0100 Original-Received: from localhost ([::1]:45960 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n4Uxg-0006aj-84 for ged-emacs-devel@m.gmane-mx.org; Mon, 03 Jan 2022 16:33:48 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:59418) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n4Ux0-0005tX-DV for emacs-devel@gnu.org; Mon, 03 Jan 2022 16:33:06 -0500 Original-Received: from colin.muc.de ([193.149.48.1]:35717 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.90_1) (envelope-from ) id 1n4Uwy-0007LV-CT for emacs-devel@gnu.org; Mon, 03 Jan 2022 16:33:06 -0500 Original-Received: (qmail 37948 invoked by uid 3782); 3 Jan 2022 21:33:01 -0000 Original-Received: from acm.muc.de (p4fe15534.dip0.t-ipconnect.de [79.225.85.52]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Mon, 03 Jan 2022 22:33:01 +0100 Original-Received: (qmail 20281 invoked by uid 1000); 3 Jan 2022 21:33:01 -0000 Content-Disposition: inline In-Reply-To: X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.1; envelope-from=acm@muc.de; helo=mail.muc.de X-Spam_score_int: 0 X-Spam_score: 0.0 X-Spam_bar: / X-Spam_report: (0.0 / 5.0 requ) SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:284104 Archived-At: Hello again, Stefan. On Mon, Jan 03, 2022 at 16:15:32 -0500, Stefan Monnier wrote: > > Debugger entered--Lisp error: (quit) > > copy-tree((1 . #1) t) > > macroexp-strip-symbol-positions((1 . #1)) > > byte-compile-constant((1 . #1)) > > byte-compile-quote('(1 . #2)) > > byte-compile-form('(1 . #2)) > >> The #1 means "the second heap object between the root and here" and in > >> (1 . #1) there's only one heap object. > > I can cope with "the second heap object", but what is "the root"? > I suspect in the above backtrace, every arglist is passed to print as > is, so the "root" is the arglist. > >> (1 . #1) > > Yes. Looking at seq-tests.el, it's clear the original source for it is > > (let ((l1 '#1=(1 . #1#))) ....) > Ah, one of those rare cases where the source code includes circular data. Yes. But the current byte-compiler copes with it. The version I have in scratch/correct-warning-pos doesn't, because of that copy-tree call (and possibly the further processing in macroexp-strip-symbol-positions, too). > Maybe we should apply the patch below. Hmm. That feels like papering over the problem rather than solving it. > Stefan > diff --git a/test/lisp/emacs-lisp/seq-tests.el b/test/lisp/emacs-lisp/seq-tests.el > index 9e5d59163f9..48ed72a1b06 100644 > --- a/test/lisp/emacs-lisp/seq-tests.el > +++ b/test/lisp/emacs-lisp/seq-tests.el > @@ -474,7 +474,8 @@ test-sequences-oddp > (should-error (seq-random-elt ""))) > (ert-deftest test-seq-mapn-circular-lists () > - (let ((l1 '#1=(1 . #1#))) > + (let ((l1 (list 1))) > + (setcdr l1 l1) > (should (equal (seq-mapn #'+ '(3 4 5 7) l1) > '(4 5 6 8))))) -- Alan Mackenzie (Nuremberg, Germany).