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 2C9FAC433ED for ; Tue, 27 Apr 2021 15:09:12 +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 9435960FEE for ; Tue, 27 Apr 2021 15:09:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9435960FEE 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]:50628 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lbPKo-0003x5-EM for qemu-devel@archiver.kernel.org; Tue, 27 Apr 2021 11:09:10 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53182) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lbPFw-0006iy-9d for qemu-devel@nongnu.org; Tue, 27 Apr 2021 11:04:08 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37965) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lbPFk-0007ms-60 for qemu-devel@nongnu.org; Tue, 27 Apr 2021 11:04:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619535835; 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=ytenhs6DNe1dHuWHuze4jDe5Nt/tAOc38YdqDTP+F3k=; b=HZH3/g4Dq/z1il0ZpR9uK++yVl1IgKUpAVqAg5D8a2G8m2ioqovt5IvHxqDp4cGnMLL25+ OlKg9ucSoQYh6hY6p4LEZmleqH/XRv9RqvR9DG84qFyICaI0W0kxrDlChcu9cVF8ZJ5gkV mYi7AkkcNGSdfYQmYWVVcUVzZhTQ0I4= 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-573-awKTFjQKN0mqhmocBpjrIQ-1; Tue, 27 Apr 2021 11:03:51 -0400 X-MC-Unique: awKTFjQKN0mqhmocBpjrIQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E6BCD107ACE3; Tue, 27 Apr 2021 15:03:50 +0000 (UTC) Received: from [10.10.112.236] (ovpn-112-236.rdu2.redhat.com [10.10.112.236]) by smtp.corp.redhat.com (Postfix) with ESMTP id 329A85D769; Tue, 27 Apr 2021 15:03:50 +0000 (UTC) Subject: Re: [PATCH 06/22] qapi/parser: assert get_expr returns object in outer loop To: Markus Armbruster References: <20210422030720.3685766-1-jsnow@redhat.com> <20210422030720.3685766-7-jsnow@redhat.com> <87im4a96a2.fsf@dusky.pond.sub.org> From: John Snow Message-ID: Date: Tue, 27 Apr 2021 11:03:49 -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: <87im4a96a2.fsf@dusky.pond.sub.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.218, 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=unavailable 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 , qemu-devel@nongnu.org, Eduardo Habkost , Cleber Rosa Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 4/25/21 3:23 AM, Markus Armbruster wrote: > John Snow writes: > >> get_expr can return many things, depending on where it is used. In the >> outer parsing loop, we expect and require it to return a dict. >> >> (It's (maybe) a bit involved to teach mypy that when nested is False, >> this is already always True. I'll look into it later, maybe.) >> >> Signed-off-by: John Snow >> --- >> scripts/qapi/parser.py | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py >> index c75434e75a5..6b443b1247e 100644 >> --- a/scripts/qapi/parser.py >> +++ b/scripts/qapi/parser.py >> @@ -78,6 +78,8 @@ def _parse(self): >> continue >> >> expr = self.get_expr(False) >> + assert isinstance(expr, dict) # Guaranteed when nested=False >> + >> if 'include' in expr: >> self.reject_expr_doc(cur_doc) >> if len(expr) != 1: >> @@ -278,6 +280,7 @@ def get_values(self): >> self.accept() >> >> def get_expr(self, nested): >> + # TODO: Teach mypy that nested=False means the retval is a Dict. >> if self.tok != '{' and not nested: >> raise QAPIParseError(self, "expected '{'") >> if self.tok == '{': > > The better place to assert a post condition would be ... > > self.accept() > expr = self.get_members() > elif self.tok == '[': > self.accept() > expr = self.get_values() > elif self.tok in "'tf": > expr = self.val > self.accept() > else: > raise QAPIParseError( > self, "expected '{', '[', string, or boolean") > > ... here. > > return expr > > But then it may not help mypy over the hump, which is the whole point of > the patch. > Right, the problem is that 'expr' here actually doesn't have to be a Dict. It can be a List, str, or bool too. The type narrowing occurs only when you pass nested=False. > Alternative ways to skin this cat: > > * Split get_object() off get_expr(). > > diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py > index ca5e8e18e0..c79b3c7d08 100644 > --- a/scripts/qapi/parser.py > +++ b/scripts/qapi/parser.py > @@ -262,9 +262,12 @@ def get_values(self): > raise QAPIParseError(self, "expected ',' or ']'") > self.accept() > > - def get_expr(self, nested): > - if self.tok != '{' and not nested: > + def get_object(self): > + if self.tok != '{': > raise QAPIParseError(self, "expected '{'") > + return self.get_expr() > + > + def get_expr(self): > if self.tok == '{': > self.accept() > expr = self.get_members() > That'd work well. no @overload. > * Shift "top-level expression must be dict" up: > > diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py > index ca5e8e18e0..ee8cbf3531 100644 > --- a/scripts/qapi/parser.py > +++ b/scripts/qapi/parser.py > @@ -68,7 +68,10 @@ def __init__(self, fname, previously_included=None, incl_info=None): > self.docs.append(cur_doc) > continue > > - expr = self.get_expr(False) > + expr = self.get_expr() > + if not isinstance(expr, OrderedDict): > + raise QAPISemError( > + info, "top-level expression must be an object") Also works. As a benefit (to both previous suggestions), it leaves get_expr completely generic and expresses the grammatical constraint up here in the parseloop. It leaves the JSON parsing more generic and further consolidates QAPI Schema specific stuff to this region. > if 'include' in expr: > self.reject_expr_doc(cur_doc) > if len(expr) != 1: > @@ -262,9 +265,7 @@ def get_values(self): > raise QAPIParseError(self, "expected ',' or ']'") > self.accept() > > - def get_expr(self, nested): > - if self.tok != '{' and not nested: > - raise QAPIParseError(self, "expected '{'") > + def get_expr(self): > if self.tok == '{': > self.accept() > expr = self.get_members() > > * Shift it further, into expr.py: > > diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py > index 496f7e0333..0a83c493a0 100644 > --- a/scripts/qapi/expr.py > +++ b/scripts/qapi/expr.py > @@ -600,7 +600,10 @@ def check_exprs(exprs: List[_JSONObject]) -> List[_JSONObject]: > """ > for expr_elem in exprs: > # Expression > - assert isinstance(expr_elem['expr'], dict) > + if not isinstance(expr_elem['expr'], dict): > + raise QAPISemError( > + info, "top-level expression must be an object") > + > for key in expr_elem['expr'].keys(): > assert isinstance(key, str) > expr: _JSONObject = expr_elem['expr'] > > Shifting it up would be closer to qapi-code-gen.txt than what we have > now. > This is also pretty nice, as it furthers the splitting of the JSON syntax from the abstract QAPI syntax, which is a distinct end-goal I have. A slight downside is that the type of a value now needs to follow outside of parser.py, which will warrant a type name. > All observations, no demands. >