Received: (at 51412) by debbugs.gnu.org; 14 Sep 2022 18:38:59 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Wed Sep 14 14:38:59 2022 Received: from localhost ([127.0.0.1]:56228 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1oYXHn-0006na-9n for submit <at> debbugs.gnu.org; Wed, 14 Sep 2022 14:38:59 -0400 Received: from quimby.gnus.org ([95.216.78.240]:52874) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <larsi@HIDDEN>) id 1oYXHm-0006nN-3j for 51412 <at> debbugs.gnu.org; Wed, 14 Sep 2022 14:38:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnus.org; s=20200322; h=Content-Transfer-Encoding:Content-Type:MIME-Version:Message-ID :Date:References:In-Reply-To:Subject:Cc:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=+lPJPWs0uHv0GpbpTCg1Uicw+u4BC7ulVKt/J6c7h6o=; b=PeioOPLcKurqeCOZtC97kw1BhN tuZTAkthEH7zqLpJu6yJ+DS0wa/DWnZq2757MsHP3q9mMHQHGnbaatQcd4w7vY3wVhrMI7ln4hsng 2ZVzOi1Ep0gpERjXwfawbxwFyD80zwG+lh7s8LBaopkfj7NnCi2tndK2VmuxqRiCzwLw=; Received: from [84.212.220.105] (helo=joga) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from <larsi@HIDDEN>) id 1oYXHc-0001VC-33; Wed, 14 Sep 2022 20:38:50 +0200 From: Lars Ingebrigtsen <larsi@HIDDEN> To: akater <nuclearspace@HIDDEN> Subject: Re: bug#51412: 29.0.50; cl--mapcar-many fails inconsistently in the presence of circular lists; other shortcomings In-Reply-To: <87ee88dmzb.fsf@HIDDEN> (akater's message of "Tue, 26 Oct 2021 11:50:00 +0000") References: <87ee88dmzb.fsf@HIDDEN> X-Now-Playing: Scout Niblett's _Uptown Top Ranking_: "Dare!" Date: Wed, 14 Sep 2022 20:38:45 +0200 Message-ID: <87leql3ioa.fsf@HIDDEN> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Report: Spam detection software, running on the system "quimby.gnus.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: akater <nuclearspace@HIDDEN> writes: > cl--mapcar-many is used as a backend for implementing several cl- > functions in cl-extra. To deal with arbitrary number of arguments > (passed to cl--mapcar-many as list cl-seq), it goes through th [...] Content analysis details: (-2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 51412 Cc: 51412 <at> debbugs.gnu.org, Stefan Monnier <monnier@HIDDEN> X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) akater <nuclearspace@HIDDEN> writes: > cl--mapcar-many is used as a backend for implementing several cl- > functions in cl-extra. To deal with arbitrary number of arguments > (passed to cl--mapcar-many as list cl-seq), it goes through them all > whenever there are more than 2, in advance, and attempts to compute the > minimal length. > > This fails if any of the arguments is a circular list. > > To reproduce, just evaluate (cl-map 'list #'identity '#1=3D(a . #1#) nil = nil). Debugger entered--Lisp error: (circular-list (a . #2)) > Note that (cl-map 'list #'identity '#1=3D(a . #1#) nil) doesn't fail so > this is at the very least inconsistent. N.B.: CL spec says =E2=80=9CShou= ld be > prepared to signal an error=E2=80=9D for improper lists for such function= s. > Long story short, this means circular lists can be supported by CL > implementations according to CL spec. It's inconsistent, so that should probably be fixed. But isn't signalling an error here the right thing to do? But I guess as long as not all the lists are circular, then it's fine to return something here... Perhaps Stafan has some comments; added to the CCs.
bug-gnu-emacs@HIDDEN:bug#51412; Package emacs.
Full text available.Received: (at submit) by debbugs.gnu.org; 26 Oct 2021 12:01:57 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Tue Oct 26 08:01:57 2021 Received: from localhost ([127.0.0.1]:45317 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1mfL9Q-0005BV-TN for submit <at> debbugs.gnu.org; Tue, 26 Oct 2021 08:01:57 -0400 Received: from lists.gnu.org ([209.51.188.17]:33848) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <nuclearspace@HIDDEN>) id 1mfL9P-0005BO-OR for submit <at> debbugs.gnu.org; Tue, 26 Oct 2021 08:01:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44168) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <nuclearspace@HIDDEN>) id 1mfL9M-0007VB-ER for bug-gnu-emacs@HIDDEN; Tue, 26 Oct 2021 08:01:55 -0400 Received: from mail-ed1-x52d.google.com ([2a00:1450:4864:20::52d]:38739) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from <nuclearspace@HIDDEN>) id 1mfL9H-0001M6-0w for bug-gnu-emacs@HIDDEN; Tue, 26 Oct 2021 08:01:52 -0400 Received: by mail-ed1-x52d.google.com with SMTP id r4so12621940edi.5 for <bug-gnu-emacs@HIDDEN>; Tue, 26 Oct 2021 05:01:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=k4LkBQQBcmQ/oLrAxv2mnvaSkiWuzopAviPVfPW4ays=; b=GBNGDBSUhs8EWHAOwbAtXntHgI4BjfTGRJPWkCalV2tmEx3xrP3bLTUw0/aq9yf0A7 l3IsRurFF7gL8iACj+aiHI3M2E3D9VYbwo+55lo2AnBULUZXNzwYNnyYPV/kDi3+bxxl SnCHSOunku6z9h34gDDuZ53NhPIIVmShOfONtYCtQ8ZZwW0xJ2zk6yU9D0rTf7AlCea1 vc6JW3yghNFrWcysedq+JJM6rh0lw5p2mI45eWZ6qUg3xuVF0dWVpjFkdqnN7/xmuTr/ co1r48HUMap3U0AiHJhnRpcL4htxo1Obrff5d82DQfnnHa4jGIBzaxlNJ99xGSPBY4IX hAkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=k4LkBQQBcmQ/oLrAxv2mnvaSkiWuzopAviPVfPW4ays=; b=1PSKqrmFLeak3dTv8k7wu0zZFqMKv0N25CpA2NF6/UvOFIKGMw2wiHzwZCI+WVLtKP T0/ke1QjGZtXRf43/mjZHNiS76/epEm5wK6X8Cb10NddgAvq9JgLY0LkdNajtcPqx+mP aiRqoLY4ceTeqNXvKUSeUTZvZ9S2QUxM5EV71+YC1ic0GQPC5HpjXUqIasM9PwZ2QI+C n6q5KlLnI5ka2uw5+yxRMGg+2rYm53JrOjrI6mir73qarukLWXXZdhdbwKxQzxLfOC01 3OOIaEW31SKkncOJSOQjydy3AqvfO9Mi7SU8h9zqgo31VjRf/I06jb/P2p2m1QT/FZJf z00w== X-Gm-Message-State: AOAM532Oe0gs9Wwh6kwxUDu4smk0sdcdbFHqgRm8dHMVtL7D+H7tEK67 V1xSX1rWcwkrREFulGjd1/lv7sFoHHw= X-Google-Smtp-Source: ABdhPJzV949VTyC2t5MX3/3juod4OOFRjpemP6FxmoAmsq1tedR3Dcln1Al2iz25CqaY+4xZ8UPpgg== X-Received: by 2002:a17:906:a14a:: with SMTP id bu10mr28615110ejb.540.1635249696418; Tue, 26 Oct 2021 05:01:36 -0700 (PDT) Received: from localhost ([185.31.175.226]) by smtp.googlemail.com with ESMTPSA id e6sm4557066ejs.112.2021.10.26.05.01.35 for <bug-gnu-emacs@HIDDEN> (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Oct 2021 05:01:36 -0700 (PDT) From: akater <nuclearspace@HIDDEN> To: bug-gnu-emacs@HIDDEN Subject: 29.0.50; cl--mapcar-many fails inconsistently in the presence of circular lists; other shortcomings Date: Tue, 26 Oct 2021 11:50:00 +0000 Message-ID: <87ee88dmzb.fsf@HIDDEN> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::52d; envelope-from=nuclearspace@HIDDEN; helo=mail-ed1-x52d.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Spam-Score: -1.3 (-) X-Debbugs-Envelope-To: submit X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -2.3 (--) cl--mapcar-many is used as a backend for implementing several cl- functions in cl-extra. To deal with arbitrary number of arguments (passed to cl--mapcar-many as list cl-seq), it goes through them all whenever there are more than 2, in advance, and attempts to compute the minimal length. This fails if any of the arguments is a circular list. To reproduce, just evaluate (cl-map 'list #'identity '#1=3D(a . #1#) nil ni= l). Note that (cl-map 'list #'identity '#1=3D(a . #1#) nil) doesn't fail so this is at the very least inconsistent. N.B.: CL spec says =E2=80=9CShould= be prepared to signal an error=E2=80=9D for improper lists for such functions. Long story short, this means circular lists can be supported by CL implementations according to CL spec. Other shortcomings: going through all sequences in advance is very inefficient. mapcar-many also checks sequence types at runtime even though they are known in advance which is also wasteful. The mechanism used in recent suggested implementation of cl-map-into https://lists.gnu.org/archive/html/emacs-devel/2021-10/msg00636.html could be used to reimplement other sequence-oriented cl-extra functions and resolve these issues, if it's merged. I wrote some supporting macros there with a view towards this use; this bug report is partially an apology for them.
akater <nuclearspace@HIDDEN>:bug-gnu-emacs@HIDDEN.
Full text available.bug-gnu-emacs@HIDDEN:bug#51412; Package emacs.
Full text available.
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997 nCipher Corporation Ltd,
1994-97 Ian Jackson.