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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 71BDDC433B4 for ; Tue, 18 May 2021 15:33:23 +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 01CF461184 for ; Tue, 18 May 2021 15:33:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01CF461184 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]:53528 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lj1ik-0004YX-21 for qemu-devel@archiver.kernel.org; Tue, 18 May 2021 11:33:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34452) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lj1Vs-0004Ff-SJ for qemu-devel@nongnu.org; Tue, 18 May 2021 11:20:06 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37800) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lj1Vm-0005oS-Tc for qemu-devel@nongnu.org; Tue, 18 May 2021 11:20:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621351196; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=l3j7Q607Vvi3tQg8Yo82gMyj/seKmWfPL8a4bKPZNcA=; b=XKSe2fWA4NNiiyPqgahZD2AsMiSCdbLyrOOinn0szk0hukyoy0i2+35JEY34YR/ZAiixvr oAP6QbBCWLhswEn05L6ikqsBQaSHcqYKuKLcwbjUQRPoILoIEZWerjD5M7dElX/OWvuDnZ aFbpxP/pto5cBY32O3VpTaInzcPEg3w= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-241-aupUfMuvPTyk3KCvt5semQ-1; Tue, 18 May 2021 11:19:53 -0400 X-MC-Unique: aupUfMuvPTyk3KCvt5semQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 866FF9609B0; Tue, 18 May 2021 15:19:30 +0000 (UTC) Received: from [10.10.117.64] (ovpn-117-64.rdu2.redhat.com [10.10.117.64]) by smtp.corp.redhat.com (Postfix) with ESMTP id 51A125C1CF; Tue, 18 May 2021 15:19:26 +0000 (UTC) Subject: Re: [PATCH v2 05/21] qapi/parser: Assert lexer value is a string To: Markus Armbruster References: <20210511220601.2110055-1-jsnow@redhat.com> <20210511220601.2110055-6-jsnow@redhat.com> <87lf8c5pid.fsf@dusky.pond.sub.org> From: John Snow Message-ID: <504f3b32-67b8-4c20-bf82-f2d994ffe1b7@redhat.com> Date: Tue, 18 May 2021 11:19:25 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <87lf8c5pid.fsf@dusky.pond.sub.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jsnow@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.374, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: Michael Roth , Cleber Rosa , qemu-devel@nongnu.org, Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/18/21 6:02 AM, Markus Armbruster wrote: > John Snow writes: > >> The type checker can't narrow the type of the token value to string, >> because it's only loosely correlated with the return token. >> >> We know that a token of '#' should always have a "str" value. >> Add an assertion. >> >> Signed-off-by: John Snow >> --- >> scripts/qapi/parser.py | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py >> index d620706fffb..ba17f1357ad 100644 >> --- a/scripts/qapi/parser.py >> +++ b/scripts/qapi/parser.py >> @@ -304,6 +304,7 @@ def get_doc(self, info): >> cur_doc = QAPIDoc(self, info) >> self.accept(False) >> while self.tok == '#': >> + assert isinstance(self.val, str) # comment token MUST have str val > > What does the comment add to the assertion? Isn't it all obvious? Just > wondering; if you genuinely think it isn't, I'm not going to argue. > Except about the long line, which you could easily avoid: > Yeah, I just suppose it's an artifact from when I was first reading this code. It wasn't necessarily obvious to me that comment tokens -- which are sometimes squelched -- must always have a str val that is non-None. I felt like adding an assertion here required SOME kind of justification for WHY it was true. Since the val can be None *and* the lexer can omit comments, it seemed not expressly self-evident at the time. Less obvious than, say, why 'tf' values will definitely be True/False. Maybe just my own brain bug. I'm not as attached to it as other things at this point anymore, having spent more time in this file since I first wrote it. Remove if you'd like. The commit message can perform the duty of explaining more deeply if people need. > assert isinstance(self.val, str) # comment value MUST be str > >> if self.val.startswith('##'): >> # End of doc comment >> if self.val != '##':