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 64E53C5AD4C for ; Thu, 23 Nov 2023 13:04:33 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r69Mw-00052T-PA; Thu, 23 Nov 2023 08:03:46 -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 1r69Mn-00052E-Bv for qemu-devel@nongnu.org; Thu, 23 Nov 2023 08:03:37 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r69Mk-0004HF-A8 for qemu-devel@nongnu.org; Thu, 23 Nov 2023 08:03:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1700744612; 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=sRfRViJx5c9sIY8HTNoyDt5asDdzttHRKjxmh5QnqRI=; b=NTehxlQ7EAOjEMm4FAV8MbhRolYe9lgcqwYQP9vQ7gmC6pyMh9Sp2AUGZJ2Bb5fasM5Wmu jaesQi5s2f3MYkid4us+YFNMz0IflIJs6ib9XwP/qNEFpYV3SIiWrrHVhXJSop6YoRWWG7 PulN8OqjswgglqpijEr48V5HkFVdpdU= 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-668-sgX7ewUcNHGXyB8xDM4J1w-1; Thu, 23 Nov 2023 08:03:26 -0500 X-MC-Unique: sgX7ewUcNHGXyB8xDM4J1w-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 6F7113806702; Thu, 23 Nov 2023 13:03:26 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.148]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 33D9E492BFC; Thu, 23 Nov 2023 13:03:26 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 434C121E6A1F; Thu, 23 Nov 2023 14:03:25 +0100 (CET) From: Markus Armbruster To: John Snow Cc: qemu-devel@nongnu.org, Peter Maydell , Michael Roth Subject: Re: [PATCH 11/19] qapi/schema: fix QAPISchemaArrayType.check's call to resolve_type References: <20231116014350.653792-1-jsnow@redhat.com> <20231116014350.653792-12-jsnow@redhat.com> <874jhedjv0.fsf@pond.sub.org> Date: Thu, 23 Nov 2023 14:03:25 +0100 In-Reply-To: (John Snow's message of "Wed, 22 Nov 2023 10:58:02 -0500") Message-ID: <87wmu84o6a.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=170.10.133.124; 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_H3=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: > On Wed, Nov 22, 2023 at 7:59=E2=80=AFAM Markus Armbruster wrote: >> >> John Snow writes: >> >> > There's more conditionals in here than we can reasonably pack into a >> > terse little statement, so break it apart into something more explicit. >> > >> > (When would a built-in array ever cause a QAPISemError? I don't know, >> > maybe never - but the type system wasn't happy all the same.) >> > >> > Signed-off-by: John Snow >> > --- >> > scripts/qapi/schema.py | 11 +++++++++-- >> > 1 file changed, 9 insertions(+), 2 deletions(-) >> > >> > diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py >> > index 462acb2bb61..164d86c4064 100644 >> > --- a/scripts/qapi/schema.py >> > +++ b/scripts/qapi/schema.py >> > @@ -384,9 +384,16 @@ def need_has_if_optional(self): >> > >> > def check(self, schema): >> > super().check(schema) >> > + >> > + if self.info: >> > + assert self.info.defn_meta # guaranteed to be set by exp= r.py >> > + what =3D self.info.defn_meta >> > + else: >> > + what =3D 'built-in array' >> > + >> > self._element_type =3D schema.resolve_type( >> > - self._element_type_name, self.info, >> > - self.info and self.info.defn_meta) >> > + self._element_type_name, self.info, what >> > + ) 0>> > assert not isinstance(self.element_type, QAPISchemaArrayType) >> > >> > def set_module(self, schema): >> >> What problem are you solving here? >> > > 1. "self.info and self.info.defn_meta" is the wrong type ifn't self.info self.info is Optional[QAPISourceInfo]. When self.info, then self.info.defn_meta is is Optional[str]. Naive me expects self.info and self.info.defn_meta to be Optional[str]. Playing with mypy... it seems to be Union[QAPISourceInfo, None, str]. Type inference too weak. > 2. self.info.defn_meta is *also* not guaranteed by static types Yes. We know it's not None ("guaranteed to be set by expr.py"), but the type system doesn't. > ultimately: we need to assert self.info and self.info.defn_meta both; > but it's possible (?) that we don't have self.info in the case that > we're a built-in array, so I handle that. This bring us back to the question in your commit message: "When would a built-in array ever cause a QAPISemError?" Short answer: never. Long answer. We're dealing with a *specific* QAPISemError here, namely .resolve_type()'s "uses unknown type". If this happens for a built-in array, it's a programming error. Let's commit such an error to see what happens: stick self._make_array_type('xxx', None) Dies like this: Traceback (most recent call last): File "/work/armbru/qemu/scripts/qapi/main.py", line 94, in main generate(args.schema, File "/work/armbru/qemu/scripts/qapi/main.py", line 50, in generate schema =3D QAPISchema(schema_file) ^^^^^^^^^^^^^^^^^^^^^^^ File "/work/armbru/qemu/scripts/qapi/schema.py", line 938, in __init__ self.check() File "/work/armbru/qemu/scripts/qapi/schema.py", line 1225, in check ent.check(self) File "/work/armbru/qemu/scripts/qapi/schema.py", line 373, in check self.element_type =3D schema.resolve_type( ^^^^^^^^^^^^^^^^^^^^ File "/work/armbru/qemu/scripts/qapi/schema.py", line 973, in resolve= _type raise QAPISemError( qapi.error.QAPISemError: During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/work/armbru/qemu/scripts/qapi-gen.py", line 19, in sys.exit(main.main()) ^^^^^^^^^^^ File "/work/armbru/qemu/scripts/qapi/main.py", line 101, in main print(err, file=3Dsys.stderr) File "/work/armbru/qemu/scripts/qapi/error.py", line 41, in __str__ assert self.info is not None ^^^^^^^^^^^^^^^^^^^^^ AssertionError Same before and after your patch. The patch's change of what=3DNone to what=3D'built-in array' has no effect. Here's a slightly simpler patch: diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py index 46004689f0..feb0023d25 100644 --- a/scripts/qapi/schema.py +++ b/scripts/qapi/schema.py @@ -479,7 +479,7 @@ def check(self, schema: QAPISchema) -> None: super().check(schema) self._element_type =3D schema.resolve_type( self._element_type_name, self.info, - self.info and self.info.defn_meta) + self.info.defn_meta if self.info else None) assert not isinstance(self.element_type, QAPISchemaArrayType) =20 def set_module(self, schema: QAPISchema) -> None: @@ -1193,7 +1193,7 @@ def resolve_type( self, name: str, info: Optional[QAPISourceInfo], - what: Union[str, Callable[[Optional[QAPISourceInfo]], str]], + what: Union[None, str, Callable[[Optional[QAPISourceInfo]], str]], ) -> QAPISchemaType: typ =3D self.lookup_type(name) if not typ: The first hunk works around mypy's type inference weakness. It rewrites A and B as B if A else A and then partially evaluates to B if A else None exploiting the fact that falsy A can only be None. It replaces this patch. The second hunk corrects .resolve_type()'s typing to accept what=3DNone. It's meant to be squashed into PATCH 16. What do you think?