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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 28318C5AD4C for ; Thu, 23 Nov 2023 14:13:25 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r6ARe-0000OI-10; Thu, 23 Nov 2023 09:12:42 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r6ARc-0000O8-2S for qemu-devel@nongnu.org; Thu, 23 Nov 2023 09:12:40 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r6ARa-0001H8-91 for qemu-devel@nongnu.org; Thu, 23 Nov 2023 09:12:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1700748756; 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=3/xz6mYIYcAx5LHKYlcJQpn+uer2uLsSzI32X8bGY5c=; b=NcVkwAaPKVs8UfAp9dzIqzR9dZC3NW6djFJryODKckhHqHDvgBeqmOVT41Mjj0ibXU6NJW Tewc9vfGvnriT1SqwYPbOhNmdeLaVEsVlGcSWgor6GXz/mNExkwP57Bk2SEaGBlgJsD0aP PeP3M3Fa/0Q4JHtaHyjRLeUPcWOghWc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-163-_MOt5hUrNI2znSCVT2U9Cw-1; Thu, 23 Nov 2023 09:12:33 -0500 X-MC-Unique: _MOt5hUrNI2znSCVT2U9Cw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B64DD80C827; Thu, 23 Nov 2023 14:12:32 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.148]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 95E94492BFA; Thu, 23 Nov 2023 14:12:32 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 8D75C21E6A1F; Thu, 23 Nov 2023 15:12:31 +0100 (CET) From: Markus Armbruster To: John Snow Cc: qemu-devel@nongnu.org, Peter Maydell , Michael Roth , Markus Armbruster Subject: Re: [PATCH 15/19] qapi/parser: demote QAPIExpression to Dict[str, Any] References: <20231116014350.653792-1-jsnow@redhat.com> <20231116014350.653792-16-jsnow@redhat.com> Date: Thu, 23 Nov 2023 15:12:31 +0100 In-Reply-To: <20231116014350.653792-16-jsnow@redhat.com> (John Snow's message of "Wed, 15 Nov 2023 20:43:46 -0500") Message-ID: <8734ww4kz4.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.058, 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_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org John Snow writes: > Dict[str, object] is a stricter type, but with the way that code is > currently arranged, it is infeasible to enforce this strictness. > > In particular, although expr.py's entire raison d'=C3=AAtre is normalizat= ion > and type-checking of QAPI Expressions, that type information is not > "remembered" in any meaningful way by mypy because each individual > expression is not downcast to a specific expression type that holds all > the details of each expression's unique form. > > As a result, all of the code in schema.py that deals with actually > creating type-safe specialized structures has no guarantee (myopically) > that the data it is being passed is correct. > > There are two ways to solve this: > > (1) Re-assert that the incoming data is in the shape we expect it to be, = or > (2) Disable type checking for this data. > > (1) is appealing to my sense of strictness, but I gotta concede that it > is asinine to re-check the shape of a QAPIExpression in schema.py when > expr.py has just completed that work at length. The duplication of code > and the nightmare thought of needing to update both locations if and > when we change the shape of these structures makes me extremely > reluctant to go down this route. > > (2) allows us the chance to miss updating types in the case that types > are updated in expr.py, but it *is* an awful lot simpler and, > importantly, gets us closer to type checking schema.py *at > all*. Something is better than nothing, I'd argue. > > So, do the simpler dumber thing and worry about future strictness > improvements later. Yes. While Dict[str, object] is stricter than Dict[str, Any], both are miles away from the actual, recursive type. > Signed-off-by: John Snow > --- > scripts/qapi/parser.py | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py > index bf31018aef0..b7f08cf36f2 100644 > --- a/scripts/qapi/parser.py > +++ b/scripts/qapi/parser.py > @@ -19,6 +19,7 @@ > import re > from typing import ( > TYPE_CHECKING, > + Any, > Dict, > List, > Mapping, > @@ -43,7 +44,7 @@ > _ExprValue =3D Union[List[object], Dict[str, object], str, bool] >=20=20 >=20=20 > -class QAPIExpression(Dict[str, object]): > +class QAPIExpression(Dict[str, Any]): > # pylint: disable=3Dtoo-few-public-methods > def __init__(self, > data: Mapping[str, object], There are several occurences of Dict[str, object] elsewhere. Would your argument for dumbing down QAPIExpression apply to (some of) them, too? Skimming them, I found this in introspect.py: # These types are based on structures defined in QEMU's schema, so we # lack precise types for them here. Python 3.6 does not offer # TypedDict constructs, so they are broadly typed here as simple # Python Dicts. SchemaInfo =3D Dict[str, object] SchemaInfoEnumMember =3D Dict[str, object] SchemaInfoObject =3D Dict[str, object] SchemaInfoObjectVariant =3D Dict[str, object] SchemaInfoObjectMember =3D Dict[str, object] SchemaInfoCommand =3D Dict[str, object] Can we do better now we have 3.8?