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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 626F6C4CEC9 for ; Tue, 17 Sep 2019 20:56:45 +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 3494A20862 for ; Tue, 17 Sep 2019 20:56:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3494A20862 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]:52560 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAKWi-00085Y-4v for qemu-devel@archiver.kernel.org; Tue, 17 Sep 2019 16:56:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55677) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAKL6-0001CM-8N for qemu-devel@nongnu.org; Tue, 17 Sep 2019 16:44:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iAKL5-00048g-1R for qemu-devel@nongnu.org; Tue, 17 Sep 2019 16:44:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37534) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iAKL4-00048P-Pi for qemu-devel@nongnu.org; Tue, 17 Sep 2019 16:44:42 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 25C9B5946B; Tue, 17 Sep 2019 20:44:42 +0000 (UTC) Received: from [10.3.116.249] (ovpn-116-249.phx2.redhat.com [10.3.116.249]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B100060A9F; Tue, 17 Sep 2019 20:44:39 +0000 (UTC) To: Markus Armbruster , qemu-devel@nongnu.org References: <20190914153506.2151-1-armbru@redhat.com> <20190914153506.2151-19-armbru@redhat.com> From: Eric Blake Openpgp: preference=signencrypt Autocrypt: addr=eblake@redhat.com; keydata= xsBNBEvHyWwBCACw7DwsQIh0kAbUXyqhfiKAKOTVu6OiMGffw2w90Ggrp4bdVKmCaEXlrVLU xphBM8mb+wsFkU+pq9YR621WXo9REYVIl0FxKeQo9dyQBZ/XvmUMka4NOmHtFg74nvkpJFCD TUNzmqfcjdKhfFV0d7P/ixKQeZr2WP1xMcjmAQY5YvQ2lUoHP43m8TtpB1LkjyYBCodd+LkV GmCx2Bop1LSblbvbrOm2bKpZdBPjncRNob73eTpIXEutvEaHH72LzpzksfcKM+M18cyRH+nP sAd98xIbVjm3Jm4k4d5oQyE2HwOur+trk2EcxTgdp17QapuWPwMfhaNq3runaX7x34zhABEB AAHNHkVyaWMgQmxha2UgPGVibGFrZUByZWRoYXQuY29tPsLAegQTAQgAJAIbAwULCQgHAwUV CgkICwUWAgMBAAIeAQIXgAUCS8fL9QIZAQAKCRCnoWtKJSdDahBHCACbl/5FGkUqJ89GAjeX RjpAeJtdKhujir0iS4CMSIng7fCiGZ0fNJCpL5RpViSo03Q7l37ss+No+dJI8KtAp6ID+PMz wTJe5Egtv/KGUKSDvOLYJ9WIIbftEObekP+GBpWP2+KbpADsc7EsNd70sYxExD3liwVJYqLc Rw7so1PEIFp+Ni9A1DrBR5NaJBnno2PHzHPTS9nmZVYm/4I32qkLXOcdX0XElO8VPDoVobG6 gELf4v/vIImdmxLh/w5WctUpBhWWIfQDvSOW2VZDOihm7pzhQodr3QP/GDLfpK6wI7exeu3P pfPtqwa06s1pae3ad13mZGzkBdNKs1HEm8x6zsBNBEvHyWwBCADGkMFzFjmmyqAEn5D+Mt4P zPdO8NatsDw8Qit3Rmzu+kUygxyYbz52ZO40WUu7EgQ5kDTOeRPnTOd7awWDQcl1gGBXgrkR pAlQ0l0ReO57Q0eglFydLMi5bkwYhfY+TwDPMh3aOP5qBXkm4qIYSsxb8A+i00P72AqFb9Q7 3weG/flxSPApLYQE5qWGSXjOkXJv42NGS6o6gd4RmD6Ap5e8ACo1lSMPfTpGzXlt4aRkBfvb NCfNsQikLZzFYDLbQgKBA33BDeV6vNJ9Cj0SgEGOkYyed4I6AbU0kIy1hHAm1r6+sAnEdIKj cHi3xWH/UPrZW5flM8Kqo14OTDkI9EtlABEBAAHCwF8EGAEIAAkFAkvHyWwCGwwACgkQp6Fr SiUnQ2q03wgAmRFGDeXzc58NX0NrDijUu0zx3Lns/qZ9VrkSWbNZBFjpWKaeL1fdVeE4TDGm I5mRRIsStjQzc2R9b+2VBUhlAqY1nAiBDv0Qnt+9cLiuEICeUwlyl42YdwpmY0ELcy5+u6wz mK/jxrYOpzXKDwLq5k4X+hmGuSNWWAN3gHiJqmJZPkhFPUIozZUCeEc76pS/IUN72NfprZmF Dp6/QDjDFtfS39bHSWXKVZUbqaMPqlj/z6Ugk027/3GUjHHr8WkeL1ezWepYDY7WSoXwfoAL 2UXYsMAr/uUncSKlfjvArhsej0S4zbqim2ZY6S8aRWw94J3bSvJR+Nwbs34GPTD4Pg== Organization: Red Hat, Inc. Message-ID: Date: Tue, 17 Sep 2019 14:26:35 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190914153506.2151-19-armbru@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="npGiG3SHamhW90RMd74pmQEt3xBklp5T3" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 17 Sep 2019 20:44:42 +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 18/19] qapi: Fix excessive QAPISchemaEntity.check() recursion 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, mdroth@linux.vnet.ibm.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --npGiG3SHamhW90RMd74pmQEt3xBklp5T3 Content-Type: multipart/mixed; boundary="ZjwL4lg9oUIZwVQGDSXT98OzKzY3G3fST"; protected-headers="v1" From: Eric Blake To: Markus Armbruster , qemu-devel@nongnu.org Cc: mdroth@linux.vnet.ibm.com, marcandre.lureau@redhat.com Message-ID: Subject: Re: [PATCH 18/19] qapi: Fix excessive QAPISchemaEntity.check() recursion References: <20190914153506.2151-1-armbru@redhat.com> <20190914153506.2151-19-armbru@redhat.com> In-Reply-To: <20190914153506.2151-19-armbru@redhat.com> --ZjwL4lg9oUIZwVQGDSXT98OzKzY3G3fST Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 9/14/19 10:35 AM, Markus Armbruster wrote: > Entity checking goes back to commit ac88219a6c "qapi: New QAPISchema > intermediate representation", v2.5.0. It's designed to work as > follows: QAPISchema.check() calls .check() for all the schema's > entities. An entity's .check() recurses into another entity's > .check() only if the C struct generated for the former contains the C > struct generated for the latter (pointers don't count). This is used > to detect "object contains itself". >=20 > There are two instances of this: >=20 > * An object's C struct contains its base's C struct >=20 > QAPISchemaObjectType.check() calls self.base.check() >=20 > * An object's C struct contains its variants' C structs >=20 > QAPISchemaObjectTypeVariants().check calls v.type.check(). Since > commit b807a1e1e3 "qapi: Check for QAPI collisions involving variant > members", v2.6.0. >=20 > Sadly, this design has since eroded: >=20 > * A QAPISchemaEntity's .module becomes valid at .check(). This is > because computing it needs info and schema.fname, and because array > types get it from their element type instead. >=20 > Make it a property just like .ifcond. Extra space. >=20 > Additionally, have QAPISchemaEntity.check() assert it gets called at > most once, so the design invariant will stick this time. Neglecting > that was entirely my fault. Lengthy explanation, but it makes sense. >=20 > Signed-off-by: Markus Armbruster > --- > scripts/qapi/common.py | 74 +++++++++++++++++++++++++++++-------------= > 1 file changed, 52 insertions(+), 22 deletions(-) >=20 Took me a bit longer to read this (and refresh myself on what '@property' actually does in Python, but you're not the first user of it in qemu), but it matches the commit message. Reviewed-by: Eric Blake --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org --ZjwL4lg9oUIZwVQGDSXT98OzKzY3G3fST-- --npGiG3SHamhW90RMd74pmQEt3xBklp5T3 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAl2BM2sACgkQp6FrSiUn Q2pRnwf9GB0FgEA7JpnnqkglU/gvpM53V++NctEXrY5+7s4JJMnn3+W0Oj/SrgKV 7P3Dc3p+ah3jUeMC/UqxM+jr246DiQAghY8GgO6xu0cTQK7dP98ZGiarUq6WADeH RVOlK+hWBPqXAQmlQx3aeK2mMmqs6VqrfXqH6rZSLnjIlT2H9LRks9DWt0IENmmU 9d2DbCPL39a3xPaT+nsC8dHI6gzW08JR4Y0dbLe+LXr+bLxGJuo2wPaKlosyxlwV WEqVC0KCcxIqWlQdk04IHq/ZV5iRMWfuy/cywAKl2FYdqrF0pegU39ZPP+FcYAOl ytpaT5FDB0i59kGZxrDj6bzz/6++jA== =1y9B -----END PGP SIGNATURE----- --npGiG3SHamhW90RMd74pmQEt3xBklp5T3--