From patchwork Thu Jun 4 20:22:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Snow X-Patchwork-Id: 281366 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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 36D88C433E0 for ; Thu, 4 Jun 2020 20:24:05 +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 018ED206E6 for ; Thu, 4 Jun 2020 20:24:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gqYdZZkq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 018ED206E6 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]:53000 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jgwPE-0006Gs-7X for qemu-devel@archiver.kernel.org; Thu, 04 Jun 2020 16:24:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49436) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jgwNz-00040m-DJ for qemu-devel@nongnu.org; Thu, 04 Jun 2020 16:22:47 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:51978 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jgwNy-0005Un-Ml for qemu-devel@nongnu.org; Thu, 04 Jun 2020 16:22:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591302165; 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=4fk+MelxzBtEUkDkwDpmLT6Ud7EYaoQG87DV6PqOep4=; b=gqYdZZkqNkwnM+zp5GuDug9Kxfqv6CHKog2Rb+ba6BBf+Gsy4lqL1fmO+lXM4ehvb9DGc9 i8ny4ifXBdzNA/KaJ9FMrm9FE8pUMY1pqWDNUSkZ3HhWjDwS9IyxOef3UE0PhwD9tTUr7I Iu/BLPkpEv3FA7wrxYlGKaOmImSrWrA= 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-393-C7KrUWulMtatFYRnzwd7CQ-1; Thu, 04 Jun 2020 16:22:43 -0400 X-MC-Unique: C7KrUWulMtatFYRnzwd7CQ-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id B360519200C1; Thu, 4 Jun 2020 20:22:42 +0000 (UTC) Received: from probe.redhat.com (ovpn-117-188.rdu2.redhat.com [10.10.117.188]) by smtp.corp.redhat.com (Postfix) with ESMTP id DC5455D9D3; Thu, 4 Jun 2020 20:22:41 +0000 (UTC) From: John Snow To: qemu-devel@nongnu.org Subject: [PATCH v3 05/16] python/qmp.py: add casts to JSON deserialization Date: Thu, 4 Jun 2020 16:22:25 -0400 Message-Id: <20200604202236.25039-6-jsnow@redhat.com> In-Reply-To: <20200604202236.25039-1-jsnow@redhat.com> References: <20200604202236.25039-1-jsnow@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.81; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/04 01:31:23 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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: Kevin Wolf , Eduardo Habkost , qemu-block@nongnu.org, John Snow , Max Reitz , Cleber Rosa , philmd@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" mypy and python type hints are not powerful enough to properly describe JSON messages in Python 3.6. The best we can do, generally, is describe them as Dict[str, Any]. Add casts to coerce this type for static analysis; but do NOT enforce this type at runtime in any way. Note: Python 3.8 adds a TypedDict construct which allows for the description of more arbitrary Dictionary shapes. There is a third-party module, "Pydantic", which is compatible with 3.6 that can be used instead of the JSON library that parses JSON messages to fully-typed Python objects, and may be preferable in some cases. (That is well beyond the scope of this commit or series.) Signed-off-by: John Snow --- python/qemu/qmp.py | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/python/qemu/qmp.py b/python/qemu/qmp.py index ef3c919b76c..1ae36050a42 100644 --- a/python/qemu/qmp.py +++ b/python/qemu/qmp.py @@ -13,6 +13,7 @@ import logging from typing import ( Any, + cast, Dict, Optional, TextIO, @@ -130,7 +131,10 @@ def __json_read(self, only_event=False): data = self.__sockfile.readline() if not data: return None - resp = json.loads(data) + # By definition, any JSON received from QMP is a QMPMessage, + # and we are asserting only at static analysis time that it + # has a particular shape. + resp: QMPMessage = json.loads(data) if 'event' in resp: self.logger.debug("<<< %s", resp) self.__events.append(resp) @@ -262,7 +266,7 @@ def command(self, cmd, **kwds): ret = self.cmd(cmd, kwds) if 'error' in ret: raise QMPResponseError(ret) - return ret['return'] + return cast(QMPReturnValue, ret['return']) def pull_event(self, wait=False): """