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=-15.3 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 9C2ACC433DB for ; Mon, 8 Feb 2021 21:39:06 +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 2F06F64E66 for ; Mon, 8 Feb 2021 21:39:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F06F64E66 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]:33486 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l9EFM-0000HL-UN for qemu-devel@archiver.kernel.org; Mon, 08 Feb 2021 16:39:04 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:47076) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l98uA-0004Gy-8i for qemu-devel@nongnu.org; Mon, 08 Feb 2021 10:56:51 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:49541) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l98u4-0006zM-Ob for qemu-devel@nongnu.org; Mon, 08 Feb 2021 10:56:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612799802; 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=jjXtZRUgbY6KEo6HQjLsYj9RfV/bUDVEPNddODwm5Fk=; b=Icqwbk/tHhEiRiLBa59O4eblNz+3AUmPVSNuvXNIzhit7yspIZbhyQjd7biOfQVUB0CWKe v7q9J7ZB9+5/5oeY4t9JV5TtJnWXp5udEBV74wFV4IvUzByx1MchPBCSNy58/yn0epOPrJ kYNAmoR4KN25zoTDMLNXMuhxwlz3cZI= 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-576-3abLJ2-wPIG3nfmjxDraJA-1; Mon, 08 Feb 2021 10:56:39 -0500 X-MC-Unique: 3abLJ2-wPIG3nfmjxDraJA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C5C5580196C for ; Mon, 8 Feb 2021 15:56:38 +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 245A719C59; Mon, 8 Feb 2021 15:56:38 +0000 (UTC) Subject: Re: [PATCH v5 13/15] qapi/introspect.py: add introspect.json dummy types To: Markus Armbruster References: <20210204003207.2856909-1-jsnow@redhat.com> <20210204003207.2856909-14-jsnow@redhat.com> <87czxa36q6.fsf@dusky.pond.sub.org> From: John Snow Message-ID: <17c0e654-2aa1-7ab4-3c9b-018dc648b5ca@redhat.com> Date: Mon, 8 Feb 2021 10:56:37 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <87czxa36q6.fsf@dusky.pond.sub.org> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.57, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.265, 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: Cleber Rosa , qemu-devel@nongnu.org, Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2/8/21 10:43 AM, Markus Armbruster wrote: > John Snow writes: > >> Add some aliases that declare intent for some of the "dictly-typed" >> objects we pass around in introspect.py. >> >> Signed-off-by: John Snow >> >> --- >> >> This patch is optional, it can be dropped if desired. If it's taken, >> it's probably best to squash it with the prior patch. It is purely for >> the sake of demonstrating what the _DObject was meant to convey: a >> Python Dict that represents some JSON Object. It does not add any type >> safety in and of itself, but does have some (light) annotational >> benefit. In this case, it's usually a specific data structure from the >> QAPI Schema we are referencing, but do not have "compile-time" access to >> in Python. >> >> These are loosely typed and don't bother reproducing the exact structure >> of the real types. Python 3.6 does not have support for TypedDict >> structures, so this is as good as we can do without involving a >> third-party library (e.g. Pydantic), in which we might be able to say: >> >> >> class SchemaMetaType(str, enum.Enum): >> BUILTIN = "builtin" >> ENUM = "enum" >> ARRAY = "array" >> OBJECT = "object" >> ALTERNATE = "alternate" >> COMMAND = "command" >> EVENT = "event" >> >> >> class SchemaInfo(pydantic.BaseModel): >> name: str >> meta-type: SchemaMetaType >> features: Optional[List[str]] >> data: Union[SchemaInfoBuiltin, SchemaInfoEnum, SchemaInfoArray, >> SchemaInfoObject, SchemaInfoAlternate, SchemaInfoCommand, >> SchemaInfoEvent] >> >> >> However, the cost of reproducing and keeping these structure definitions >> in-sync between the user-defined portion of the schema and the code >> generator is likely not worth doing any such thing. However, it does >> illustrate an interesting dependency the generator has on the >> user-defined schema itself in terms of types. >> >> So, I settled on using some light types that suggest the form of the >> object instead of enforcing the form. >> >> Signed-off-by: John Snow >> --- >> scripts/qapi/introspect.py | 51 +++++++++++++++++++++++--------------- >> 1 file changed, 31 insertions(+), 20 deletions(-) >> >> diff --git a/scripts/qapi/introspect.py b/scripts/qapi/introspect.py >> index 3afcdda7446..2a39726f40a 100644 >> --- a/scripts/qapi/introspect.py >> +++ b/scripts/qapi/introspect.py >> @@ -66,10 +66,15 @@ >> _value = Union[_scalar, _nonscalar] >> TreeValue = Union[_value, 'Annotated[_value]'] >> >> -# This is an alias for an arbitrary JSON object, represented here as a Dict. >> -# It is stricter on the value type than the recursive definition above. >> -# It is used to represent SchemaInfo-related structures exclusively. >> -_DObject = Dict[str, object] >> +# 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 = Dict[str, object] >> +SchemaInfoObject = Dict[str, object] >> +SchemaInfoObjectVariant = Dict[str, object] >> +SchemaInfoObjectMember = Dict[str, object] >> +SchemaInfoCommand = Dict[str, object] >> + >> >> _NodeT = TypeVar('_NodeT', bound=_value) >> >> @@ -162,7 +167,7 @@ def __init__(self, prefix: str, unmask: bool): >> ' * QAPI/QMP schema introspection', __doc__) >> self._unmask = unmask >> self._schema: Optional[QAPISchema] = None >> - self._trees: List[Annotated[_DObject]] = [] >> + self._trees: List[Annotated[SchemaInfo]] = [] >> self._used_types: List[QAPISchemaType] = [] >> self._name_map: Dict[str, str] = {} >> self._genc.add(mcgen(''' >> @@ -234,9 +239,18 @@ def _gen_features(features: List[QAPISchemaFeature] >> ) -> List[Annotated[str]]: >> return [Annotated(f.name, f.ifcond) for f in features] >> >> - def _gen_tree(self, name: str, mtype: str, obj: _DObject, >> + def _gen_tree(self, name: str, mtype: str, obj: Dict[str, object], >> ifcond: List[str], >> features: Optional[List[QAPISchemaFeature]]) -> None: >> + """ >> + Build and append a SchemaInfo object to self._trees. >> + >> + :param name: The entity's name. >> + :param mtype: The entity's meta-type. >> + :param obj: Additional entity fields, as appropriate for the meta-type. >> + :param ifcond: List of conditionals that apply to this entire entity. >> + :param features: Optional features field for SchemaInfo. >> + """ >> comment: Optional[str] = None >> if mtype not in ('command', 'event', 'builtin', 'array'): >> if not self._unmask: >> @@ -251,8 +265,8 @@ def _gen_tree(self, name: str, mtype: str, obj: _DObject, >> self._trees.append(Annotated(obj, ifcond, comment)) >> >> def _gen_member(self, member: QAPISchemaObjectTypeMember >> - ) -> Annotated[_DObject]: >> - obj: _DObject = { >> + ) -> Annotated[SchemaInfoObjectMember]: >> + obj: SchemaInfoObjectMember = { >> 'name': member.name, >> 'type': self._use_type(member.type) >> } >> @@ -262,13 +276,9 @@ def _gen_member(self, member: QAPISchemaObjectTypeMember >> obj['features'] = self._gen_features(member.features) >> return Annotated(obj, member.ifcond) >> >> - def _gen_variants(self, tag_name: str, >> - variants: List[QAPISchemaVariant]) -> _DObject: >> - return {'tag': tag_name, >> - 'variants': [self._gen_variant(v) for v in variants]} >> - >> - def _gen_variant(self, variant: QAPISchemaVariant) -> Annotated[_DObject]: >> - obj: _DObject = { >> + def _gen_variant(self, variant: QAPISchemaVariant >> + ) -> Annotated[SchemaInfoObjectVariant]: >> + obj: SchemaInfoObjectVariant = { >> 'case': variant.name, >> 'type': self._use_type(variant.type) >> } >> @@ -300,11 +310,12 @@ def visit_object_type_flat(self, name: str, info: Optional[QAPISourceInfo], >> features: List[QAPISchemaFeature], >> members: List[QAPISchemaObjectTypeMember], >> variants: Optional[QAPISchemaVariants]) -> None: >> - obj: _DObject = {'members': [self._gen_member(m) for m in members]} >> + obj: SchemaInfoObject = { >> + 'members': [self._gen_member(m) for m in members] >> + } >> if variants: >> - obj.update(self._gen_variants(variants.tag_member.name, >> - variants.variants)) >> - >> + obj['tag'] = variants.tag_member.name >> + obj['variants'] = [self._gen_variant(v) for v in variants.variants] >> self._gen_tree(name, 'object', obj, ifcond, features) >> >> def visit_alternate_type(self, name: str, info: Optional[QAPISourceInfo], >> @@ -329,7 +340,7 @@ def visit_command(self, name: str, info: Optional[QAPISourceInfo], >> >> arg_type = arg_type or self._schema.the_empty_object_type >> ret_type = ret_type or self._schema.the_empty_object_type >> - obj: _DObject = { >> + obj: SchemaInfoCommand = { >> 'arg-type': self._use_type(arg_type), >> 'ret-type': self._use_type(ret_type) >> } > > I see what you mean by "some (light) annotational benefit". > > I figure some of is simply due to going from _DObject, a name that tells > me nothing, to SchemaInfo, which makes me go aha! > Naming is hard! Using the *exact* names seems helpful. > The remainder is having the subtypes of SchemaInfo, too. albeit without > actual type checking. Worthwhile? > For referential purposes it seems useful, at least in so far as declaring intent. When I was trying to type this series, I was not aware this module was building structures defined in introspect.json until quite late into the series. I kept wondering: "What are the valid keys here? Who consumes this?" -- It wasn't obvious. I'm leaning towards just keeping them all for the documentation benefit, though I admit it *could* mislead someone into believing it's type checked when it isn't, really. I tried to call that out with the comment at the top, which I hope suffices to diffuse that potential faith-based-landmine. > I agree it should be squashed if we want it, or parts of it. > Squash all of it, IMO. --js