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 E6824C54E60 for ; Thu, 14 Mar 2024 13:59:22 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rklbC-0000wE-5j; Thu, 14 Mar 2024 09:58:22 -0400 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 1rklb9-0000vq-Jc for qemu-devel@nongnu.org; Thu, 14 Mar 2024 09:58:19 -0400 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 1rklb8-0004QJ-0U for qemu-devel@nongnu.org; Thu, 14 Mar 2024 09:58:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710424694; 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=s+REjrBfqXfR/fb3olzXZvn2DYLroPvl7g+gFKMh8AM=; b=SZQGD4OO4JEG5ZAJUCic6IRgzvZJNsmSu/y9CQfet8Hv4JiVQUKRJmfijEUGKd734RsdJ2 r1drYS0mWvMt16goIYwQuBz9KsY//zMsjCvDtUeX86RioS77xvr7zcegZCKkf6mwgGrKKK BYPGg3niZBxdSEd/x3sjskK1HTtXHlM= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-91-EdswRYeDOwy1luuLQK48Mg-1; Thu, 14 Mar 2024 09:58:11 -0400 X-MC-Unique: EdswRYeDOwy1luuLQK48Mg-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 A014E3800BAA; Thu, 14 Mar 2024 13:58:10 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.138]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 68A67492BD0; Thu, 14 Mar 2024 13:58:10 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 6DE5121E6A24; Thu, 14 Mar 2024 14:58:09 +0100 (CET) From: Markus Armbruster To: John Snow Cc: qemu-devel , Peter Maydell , Michael Roth Subject: Re: [PATCH v4 16/23] qapi/schema: Don't initialize "members" with `None` In-Reply-To: (John Snow's message of "Thu, 14 Mar 2024 09:35:59 -0400") References: <20240313044127.49089-1-jsnow@redhat.com> <20240313044127.49089-17-jsnow@redhat.com> <87a5n19dce.fsf@pond.sub.org> Date: Thu, 14 Mar 2024 14:58:09 +0100 Message-ID: <87msr09aq6.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) 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: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.987, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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: > On Thu, Mar 14, 2024, 9:01=E2=80=AFAM Markus Armbruster wrote: > >> John Snow writes: >> >> > Declare, but don't initialize the "members" field with type >> > List[QAPISchemaObjectTypeMember]. >> > >> > This simplifies the typing from what would otherwise be >> > Optional[List[T]] to merely List[T]. This removes the need to add >> > assertions to several callsites that this value is not None - which it >> > never will be after the delayed initialization in check() anyway. >> > >> > The type declaration without initialization trick will cause accidental >> > uses of this field prior to full initialization to raise an >> > AttributeError. >> > >> > (Note that it is valid to have an empty members list, see the internal >> > q_empty object as an example. For this reason, we cannot use the empty >> > list as a replacement test for full initialization and instead rely on >> > the _checked/_check_complete fields.) >> > >> > Signed-off-by: John Snow >> > --- >> > scripts/qapi/schema.py | 12 +++++++----- >> > 1 file changed, 7 insertions(+), 5 deletions(-) >> > >> > diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py >> > index 50ebc4f12de..fb30314741a 100644 >> > --- a/scripts/qapi/schema.py >> > +++ b/scripts/qapi/schema.py >> > @@ -20,7 +20,7 @@ >> > from collections import OrderedDict >> > import os >> > import re >> > -from typing import List, Optional >> > +from typing import List, Optional, cast >> > >> > from .common import ( >> > POINTER_SUFFIX, >> > @@ -449,7 +449,7 @@ def __init__(self, name, info, doc, ifcond, featur= es, >> > self.base =3D None >> > self.local_members =3D local_members >> > self.variants =3D variants >> > - self.members =3D None >> > + self.members: List[QAPISchemaObjectTypeMember] >> > self._check_complete =3D False >> > >> > def check(self, schema): >> > @@ -482,7 +482,11 @@ def check(self, schema): >> > for m in self.local_members: >> > m.check(schema) >> > m.check_clash(self.info, seen) >> > - members =3D seen.values() >> > + >> > + # check_clash works in terms of the supertype, but local_memb= ers >> > + # is asserted to be List[QAPISchemaObjectTypeMember]. >> >> Do you mean "but self.members is declared as >> List[QAPISchemaObjectTypeMember]"? > > Argh. I meant asserted in the linguistic sense. mypy asserts it to be; not > a runtime assertion. > > I do this a lot, apparently. Okay to adjust your comment to my version? [...]