From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Lars Ingebrigtsen Newsgroups: gmane.emacs.bugs Subject: bug#56255: 28.1.50; sxhash-equal does not change when object is modified Date: Tue, 28 Jun 2022 01:00:33 +0200 Message-ID: <87r139u2y6.fsf@gnus.org> References: <87v8sm70ma.fsf@localhost> <87y1xhu34f.fsf@gnus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="38561"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: 56255@debbugs.gnu.org To: Ihor Radchenko Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue Jun 28 01:01:20 2022 Return-path: Envelope-to: geb-bug-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 1o5xjM-0009rh-Sr for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 28 Jun 2022 01:01:20 +0200 Original-Received: from localhost ([::1]:42046 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o5xjL-0007sX-Tt for geb-bug-gnu-emacs@m.gmane-mx.org; Mon, 27 Jun 2022 19:01:19 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:48278) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o5xj5-0007qo-IC for bug-gnu-emacs@gnu.org; Mon, 27 Jun 2022 19:01:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:59681) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1o5xj3-00026o-Po for bug-gnu-emacs@gnu.org; Mon, 27 Jun 2022 19:01:03 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1o5xj3-0005Ee-Nm for bug-gnu-emacs@gnu.org; Mon, 27 Jun 2022 19:01:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Lars Ingebrigtsen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 27 Jun 2022 23:01:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 56255 X-GNU-PR-Package: emacs Original-Received: via spool by 56255-submit@debbugs.gnu.org id=B56255.165637084620097 (code B ref 56255); Mon, 27 Jun 2022 23:01:01 +0000 Original-Received: (at 56255) by debbugs.gnu.org; 27 Jun 2022 23:00:46 +0000 Original-Received: from localhost ([127.0.0.1]:53578 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1o5xio-0005E4-GD for submit@debbugs.gnu.org; Mon, 27 Jun 2022 19:00:46 -0400 Original-Received: from quimby.gnus.org ([95.216.78.240]:42094) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1o5xin-0005Dt-6G for 56255@debbugs.gnu.org; Mon, 27 Jun 2022 19:00:45 -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 :In-Reply-To:Date:References: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=JixQtvrg+n22HZrBJrd86L8HfyOc2UCJdPBW8btoAv8=; b=GVVuFAUdyPLE77fB3QLfS5Iyqf D6fKS2cE0P895s7A478rJ3RTYSusJh+GjfinEpU99Q81mcrtkrQSQAgSa0f0+/OfD+/oAywgpJAJp 6vE+7z3qTjPXsw+Ec5EGM8AT/DT2OLKzE45HOKLDBiF0Acmm31YSkU/j3QJBa02CRe50=; Original-Received: from [84.212.220.105] (helo=xo) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1o5xie-0003Jl-MS; Tue, 28 Jun 2022 01:00:39 +0200 X-Now-Playing: Arthur Russell's _The Deer in The Forest (March 2 1985: Live at Roulette)_: "Singing Tractors" In-Reply-To: <87y1xhu34f.fsf@gnus.org> (Lars Ingebrigtsen's message of "Tue, 28 Jun 2022 00:56:48 +0200") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:235505 Archived-At: Lars Ingebrigtsen writes: > So I think the doc string overstates things.=20 > > -- > If (equal A B), then (=3D (sxhash-equal A) (sxhash-equal B)). > -- > > Is not remotely true, but: > > -- > If (=3D (sxhash-equal A) (sxhash-equal B)) then it's quite likely that > (equal A B), but the opposite is not true for deeply nested structures. > -- Sorry, that's all wrong, and what the doc string says is true. That is, if they're equal, then the hash is =3D. But (=3D (sxhash-equal A) (sxhash-equal B)) does not imply that (equal A B), and the doc string should say that explicitly. It's the manual that's wrong here: If the two objects are not =E2=80=98equal=E2=80=99, the values returne= d by =E2=80=98sxhash-equal=E2=80=99 are usually different, but not always; = once in a rare while, by luck, you will encounter two distinct-looking objects that give the same result from =E2=80=98sxhash-equal=E2=80=99. It's not "once in a rare while" for deeply nested structures. --=20 (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no