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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 A88B5ECE58E for ; Fri, 11 Oct 2019 06:02:49 +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 824DE20659 for ; Fri, 11 Oct 2019 06:02:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 824DE20659 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]:46110 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIo0m-00080z-Jy for qemu-devel@archiver.kernel.org; Fri, 11 Oct 2019 02:02:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49786) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIo08-0007c3-EQ for qemu-devel@nongnu.org; Fri, 11 Oct 2019 02:02:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iIo06-0000jL-0h for qemu-devel@nongnu.org; Fri, 11 Oct 2019 02:02:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54274) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iIo05-0000gy-RW for qemu-devel@nongnu.org; Fri, 11 Oct 2019 02:02:05 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 05D493090FE0 for ; Fri, 11 Oct 2019 06:02:04 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.36.118.123]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6DF601001B11; Fri, 11 Oct 2019 06:02:00 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id CB3F61138619; Fri, 11 Oct 2019 08:01:58 +0200 (CEST) From: Markus Armbruster To: Stefan Hajnoczi Subject: Re: [PATCH] trace: avoid "is" with a literal Python 3.8 warnings References: <20191010122154.10553-1-stefanha@redhat.com> Date: Fri, 11 Oct 2019 08:01:58 +0200 In-Reply-To: <20191010122154.10553-1-stefanha@redhat.com> (Stefan Hajnoczi's message of "Thu, 10 Oct 2019 13:21:54 +0100") Message-ID: <87v9svlt0p.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; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Fri, 11 Oct 2019 06:02:04 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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: "Daniel P . =?utf-8?Q?Berrang=C3=A9?=" , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Stefan Hajnoczi writes: > The following statement produces a SyntaxWarning with Python 3.8: > > if len(format) is 0: > scripts/tracetool/__init__.py:459: SyntaxWarning: "is" with a literal. = Did you mean "=3D=3D"? > > Use the conventional len(x) =3D=3D 0 syntax instead. > > Reported-by: Daniel P. Berrang=C3=A9 > Signed-off-by: Stefan Hajnoczi > --- > scripts/tracetool/__init__.py | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py > index 04279fa62e..44c118bc2a 100644 > --- a/scripts/tracetool/__init__.py > +++ b/scripts/tracetool/__init__.py > @@ -456,12 +456,12 @@ def generate(events, group, format, backends, > import tracetool >=20=20 > format =3D str(format) > - if len(format) is 0: > + if len(format) =3D=3D 0: > raise TracetoolError("format not set") > if not tracetool.format.exists(format): > raise TracetoolError("unknown format: %s" % format) >=20=20 > - if len(backends) is 0: > + if len(backends) =3D=3D 0: > raise TracetoolError("no backends specified") > for backend in backends: > if not tracetool.backend.exists(backend): For what it's worth, PEP 8 advises For sequences, (strings, lists, tuples), use the fact that empty sequences are false. Yes: if not seq: if seq: No: if len(seq): if not len(seq):