From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96AE8C4CEC5 for ; Fri, 13 Sep 2019 14:39:52 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7111A20693 for ; Fri, 13 Sep 2019 14:39:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7111A20693 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44692 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i8mjn-0001ie-CL for qemu-devel@archiver.kernel.org; Fri, 13 Sep 2019 10:39:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46856) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i8mib-0000nD-NE for qemu-devel@nongnu.org; Fri, 13 Sep 2019 10:38:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i8mia-0003F3-MC for qemu-devel@nongnu.org; Fri, 13 Sep 2019 10:38:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49682) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i8mia-0003Ee-H1 for qemu-devel@nongnu.org; Fri, 13 Sep 2019 10:38:36 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D6BC1305C3A4; Fri, 13 Sep 2019 14:38:35 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-117-142.ams2.redhat.com [10.36.117.142]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 176335D9E1; Fri, 13 Sep 2019 14:38:25 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id A0097113865F; Fri, 13 Sep 2019 16:38:23 +0200 (CEST) From: Markus Armbruster To: Eric Blake References: <20190910063724.28470-1-armbru@redhat.com> <20190910063724.28470-8-armbru@redhat.com> <88fcdceb-85f8-ff7b-97b0-588ed45ba021@redhat.com> Date: Fri, 13 Sep 2019 16:38:23 +0200 In-Reply-To: <88fcdceb-85f8-ff7b-97b0-588ed45ba021@redhat.com> (Eric Blake's message of "Tue, 10 Sep 2019 10:28:30 -0500") Message-ID: <8736h09s80.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Fri, 13 Sep 2019 14:38:35 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v2 07/16] qapi: Drop support for escape sequences other than \\ X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: marcandre.lureau@redhat.com, qemu-devel@nongnu.org, mdroth@linux.vnet.ibm.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Eric Blake writes: > On 9/10/19 1:37 AM, Markus Armbruster wrote: >> Since the previous commit restricted strings to printable ASCII, >> \uXXXX's only use is obfuscation. Drop it. >> >> This leaves \\, \/, \', and \". Since QAPI schema strings are all >> names, and names are restricted to ASCII letters, digits, hyphen, and >> underscore, none of them is useful. >> >> The latter three have no test coverage. Drop them. >> >> Keep \\ to avoid (more) gratuitous incompatibility with JSON. > > We have to parse it (to get a sane error message for someone writing > "a\b" and thinking they were getting a backspace), but we can still > reject "a\\b" as being a non-QAPI-name. An alternative might be to > reject QAPI strings the moment \ is encountered (as the only possible > use is to introduce a character that is not valid as a name), to the > point that we could check for name validity at the time we parse strings > rather than later on. Up to you. That works, too. I chose to parse \\ to keep the language a sub-language of JSON's (and Python's) at the lexical level: we reject some valid JSON (and Python) such as 'a\b'. Not treating \ special at all would accept it, but with a different meaning. Will be rejected at a higher level, so it doesn't really matter. But the reasoning involves more than just the lexical level then. >> Signed-off-by: Markus Armbruster >> --- > > >> --- a/tests/qapi-schema/escape-outside-string.err >> +++ /dev/null >> @@ -1 +0,0 @@ >> -tests/qapi-schema/escape-outside-string.json:3:27: Stray "\" > > Do we still want to test that \ is an invalid character outside of > strings (whether or not \ is also made invalid inside strings)? funny-char.json checks ';'. '\' is no different. >> +++ b/tests/qapi-schema/unknown-escape.json >> @@ -1,3 +1,3 @@ >> -# we only recognize JSON escape sequences, plus our \' extension (no \x) >> +# we only recognize \\ >> # { 'command': 'foo', 'data': {} } >> { 'command': 'foo', 'dat\x61':{} } >> > > At any rate, this change seems reasonable. > > Reviewed-by: Eric Blake Thanks!