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,URIBL_BLOCKED, 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 0AAE5C433E0 for ; Wed, 24 Feb 2021 21:48:02 +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 3064A64F06 for ; Wed, 24 Feb 2021 21:48:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3064A64F06 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]:45432 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lF20l-0000Uy-TZ for qemu-devel@archiver.kernel.org; Wed, 24 Feb 2021 16:47:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:56392) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lF1zO-0008Qn-SJ for qemu-devel@nongnu.org; Wed, 24 Feb 2021 16:46:34 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:28604) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lF1zM-0003XT-Gs for qemu-devel@nongnu.org; Wed, 24 Feb 2021 16:46:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614203190; 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=qDBaInQoI294fzyw0jMWrPWMFfFpYJMOjZ6nrTJckxw=; b=aYZgERsnYCnUEQNGHX0RwU9ye+knYBfV/Jd9EnIxxmFvTgA18bygKm1JiufUwILjoNsvtn HMCIHvdDJuSV2GGdn6DGrHq/+k0bhZhZmp8c4vVfKWiwCfuUVaStNLLzPfg9MvTv7fJxD5 8svtFXEz7XLzGIfB+gRbAct4TjhOlQE= 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-220-xxkBzi2oOQOrbXqkW6KHdA-1; Wed, 24 Feb 2021 16:46:27 -0500 X-MC-Unique: xxkBzi2oOQOrbXqkW6KHdA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 997BB100CCCC; Wed, 24 Feb 2021 21:46:26 +0000 (UTC) Received: from [10.10.112.247] (ovpn-112-247.rdu2.redhat.com [10.10.112.247]) by smtp.corp.redhat.com (Postfix) with ESMTP id C335160BF3; Wed, 24 Feb 2021 21:46:25 +0000 (UTC) Subject: Re: [PATCH v3 03/16] qapi/expr.py: constrain incoming expression types To: Markus Armbruster References: <20210223003408.964543-1-jsnow@redhat.com> <20210223003408.964543-4-jsnow@redhat.com> <8735xl7pit.fsf@dusky.pond.sub.org> From: John Snow Message-ID: <14af160f-7a06-7b9e-a770-13c1fef86ae4@redhat.com> Date: Wed, 24 Feb 2021 16:46:25 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <8735xl7pit.fsf@dusky.pond.sub.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 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=63.128.21.124; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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, 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 2/24/21 5:01 AM, Markus Armbruster wrote: > John Snow writes: > >> mypy does not know the types of values stored in Dicts that masquerade >> as objects. Help the type checker out by constraining the type. >> >> Signed-off-by: John Snow >> Reviewed-by: Eduardo Habkost >> Reviewed-by: Cleber Rosa >> --- >> scripts/qapi/expr.py | 25 ++++++++++++++++++++++--- >> 1 file changed, 22 insertions(+), 3 deletions(-) >> >> diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py >> index 5694c501fa3..783282b53ce 100644 >> --- a/scripts/qapi/expr.py >> +++ b/scripts/qapi/expr.py >> @@ -15,9 +15,17 @@ >> # See the COPYING file in the top-level directory. >> >> import re >> +from typing import MutableMapping, Optional >> >> from .common import c_name >> from .error import QAPISemError >> +from .parser import QAPIDoc >> +from .source import QAPISourceInfo >> + >> + >> +# Expressions in their raw form are JSON-like structures with arbitrary forms. >> +# Minimally, their top-level form must be a mapping of strings to values. >> +Expression = MutableMapping[str, object] > > MutableMapping, fancy. It's only ever dict. Why abstract from that? > I don't know! I referenced this in the cover letter. I cannot remember the reason anymore. It had R-Bs on it so I left it alone. There are some differences, but I no longer remember why I thought they applied. Maybe some of my more exploratory work wanted it. Dunno. > The use of object is again owed to mypy's inability to do recursive > types. What we really have here is something like > > Expression = Union[bool, str, dict[str, Expression], list[Expression]] > > with the root further constrained to the Union's dict branch. Spell > that out in a bit more detail, like you did in introspect.py? > Terminology problem? I am using "Expression" to mean very specifically a top-level object as returned from parser.py, which *must* be an Object, so it *must* be a mapping of str => yaddayadda. The type as I intended it is Expression = Dict[str, yaddayadda] where yaddayadda is Union[int, str, bool, List[yaddayadda], Dict[str, yaddayadda]] expr.py is what validates the yaddayadda, so there's no point in trying to type it further, I think. Probably worth a better comment. > Hmm, there you used Any, not object. I guess that's because mypy lets > you get away with object here, but not there. Correct? > Yep. I can get away with the stricter type here because of how we use it, so I did. That's an artifact of it not being recursive and how expr.py's entire raison d'etre is using isinstance() checks to effectively downcast for us everywhere already. > Also, PEP 8 comment line length. > Augh. Is there a way to set emacs mode highlighting in Python such that it highlights when I run past the 72-col margin, but only for comments? I have the general-purpose highlighter on for the 80-col margin. I'm not familiar with any setting like this for any of the linters or pycharm right away either. >> >> >> # Names must be letters, numbers, -, and _. They must start with letter, >> @@ -287,9 +295,20 @@ def check_event(expr, info): >> >> def check_exprs(exprs): >> for expr_elem in exprs: >> - expr = expr_elem['expr'] >> - info = expr_elem['info'] >> - doc = expr_elem.get('doc') >> + # Expression >> + assert isinstance(expr_elem['expr'], dict) >> + for key in expr_elem['expr'].keys(): >> + assert isinstance(key, str) >> + expr: Expression = expr_elem['expr'] > > You're fine with repeating exp_elem['expr'] here, and ... > >> + >> + # QAPISourceInfo >> + assert isinstance(expr_elem['info'], QAPISourceInfo) >> + info: QAPISourceInfo = expr_elem['info'] > > ... expr_elem['info'] here, but ... > >> + >> + # Optional[QAPIDoc] >> + tmp = expr_elem.get('doc') >> + assert tmp is None or isinstance(tmp, QAPIDoc) >> + doc: Optional[QAPIDoc] = tmp > > ... you avoid repetition of expr_elem.get('doc') here. Any particular > reason? > Because this looks like garbage written by a drunkard: assert expr_elem.get('doc') is None or isinstance(expr_elem.get('doc'), QAPIDoc) doc: Optional[QAPIDoc] = expr_elem.get('doc') >> >> if 'include' in expr: >> continue