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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]:49336 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kQCHE-00060o-N0 for qemu-devel@archiver.kernel.org; Wed, 07 Oct 2020 12:26:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35366) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kQBvi-00073C-SY for qemu-devel@nongnu.org; Wed, 07 Oct 2020 12:04:38 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:46222) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kQBvd-0001es-Pu for qemu-devel@nongnu.org; Wed, 07 Oct 2020 12:04:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602086671; 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=iWleI57e3a4PMyjQLi9oMuP+VZ10hg/TYZIgZHs76A0=; b=ay03qhK3UgEJzuFF6Rc1i3MgrM8CPUnsZt4Ij6FAE2LEd8/W7fTRG2msIAA0tY+5ceZo2f CV4sh+YeAFzAYnW/bV0WSGa2VjZWXnOVoA2Mzv+K27mJ9YABhAmRnca/c3j5dSjubOO1pA TPgUJSX86Hg523gqWeIS/wildGV2ELY= 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-212-Es-5BautOXmrcphl7ldU6A-1; Wed, 07 Oct 2020 12:04:29 -0400 X-MC-Unique: Es-5BautOXmrcphl7ldU6A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DE24218A822E for ; Wed, 7 Oct 2020 16:04:27 +0000 (UTC) Received: from [10.10.120.38] (ovpn-120-38.rdu2.redhat.com [10.10.120.38]) by smtp.corp.redhat.com (Postfix) with ESMTP id E033C5C1BD; Wed, 7 Oct 2020 16:04:26 +0000 (UTC) Subject: Re: [PATCH v5 24/36] qapi/source.py: add type hint annotations To: Markus Armbruster References: <20201005195158.2348217-1-jsnow@redhat.com> <20201005195158.2348217-25-jsnow@redhat.com> <87lfgicktb.fsf@dusky.pond.sub.org> From: John Snow Message-ID: Date: Wed, 7 Oct 2020 12:04:26 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <87lfgicktb.fsf@dusky.pond.sub.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/07 00:44:56 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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=-0.742, 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_NONE=-0.0001, RCVD_IN_MSPIKE_H5=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: qemu-devel@nongnu.org, Eduardo Habkost , Cleber Rosa Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/7/20 7:55 AM, Markus Armbruster wrote: > John Snow writes: > >> Annotations do not change runtime behavior. >> This commit *only* adds annotations. >> >> A note on typing of __init__: mypy requires init functions with no >> parameters to document a return type of None to be considered fully >> typed. In the case when there are input parameters, None may be omitted. >> >> Since __init__ may never return any value, it is preferred to omit the >> return annotation whenever possible. >> >> Signed-off-by: John Snow >> Reviewed-by: Eduardo Habkost >> Reviewed-by: Cleber Rosa >> Tested-by: Cleber Rosa >> --- >> scripts/qapi/mypy.ini | 5 ----- >> scripts/qapi/source.py | 31 ++++++++++++++++++------------- >> 2 files changed, 18 insertions(+), 18 deletions(-) >> >> diff --git a/scripts/qapi/mypy.ini b/scripts/qapi/mypy.ini >> index 8ab9ac52cc4..1b8555dfa39 100644 >> --- a/scripts/qapi/mypy.ini >> +++ b/scripts/qapi/mypy.ini >> @@ -34,11 +34,6 @@ disallow_untyped_defs = False >> disallow_incomplete_defs = False >> check_untyped_defs = False >> >> -[mypy-qapi.source] >> -disallow_untyped_defs = False >> -disallow_incomplete_defs = False >> -check_untyped_defs = False >> - >> [mypy-qapi.types] >> disallow_untyped_defs = False >> disallow_incomplete_defs = False >> diff --git a/scripts/qapi/source.py b/scripts/qapi/source.py >> index e97b9a8e15e..1cc6a5b82dc 100644 >> --- a/scripts/qapi/source.py >> +++ b/scripts/qapi/source.py >> @@ -11,37 +11,42 @@ >> >> import copy >> import sys >> +from typing import List, Optional, TypeVar >> >> >> class QAPISchemaPragma: >> - def __init__(self): >> + def __init__(self) -> None: >> # Are documentation comments required? >> self.doc_required = False >> # Whitelist of commands allowed to return a non-dictionary >> - self.returns_whitelist = [] >> + self.returns_whitelist: List[str] = [] >> # Whitelist of entities allowed to violate case conventions >> - self.name_case_whitelist = [] >> + self.name_case_whitelist: List[str] = [] >> >> >> class QAPISourceInfo: >> - def __init__(self, fname, line, parent): >> + T = TypeVar('T', bound='QAPISourceInfo') >> + >> + def __init__(self: T, fname: str, line: int, parent: Optional[T]): > > More ignorant questions (I'm abusing the review process to learn Python > type hints)... > > Why do you need to annotate self here, but not elsewhere? > This is admittedly me being a little extra, but I thought it was a good way to show a pattern for people who maybe hadn't been exposed to it yet. This is a pattern that allows for subclassing. I am stating that this __init__ method takes a parent of the same type as itself, whatever that happens to actually be. T is a TypeVar that we can use for Generics. By declaring the type of self as that TypeVar, we bind T to self's type. When we annotate the parent as a T, we are enforcing that the parent we receive is of the same type as ourselves. (Yep, we don't actually subclass QAPISourceInfo and I don't have plans to. It felt slightly icky to hard-code the class type name, though. I try to avoid that whenever I can. I'm not sure I would go so far as to call it a code smell or an antipattern, but it's something I tend to avoid anyway.) > Why do you use T instead of QAPISourceInfo? > >> self.fname = fname >> self.line = line >> self.parent = parent >> - self.pragma = parent.pragma if parent else QAPISchemaPragma() >> - self.defn_meta = None >> - self.defn_name = None >> + self.pragma: QAPISchemaPragma = ( >> + parent.pragma if parent else QAPISchemaPragma() >> + ) > > Type inference fail? > Yes: qapi/source.py:34: error: Cannot determine type of 'pragma' Found 1 error in 1 file (checked 14 source files) >> + self.defn_meta: Optional[str] = None >> + self.defn_name: Optional[str] = None >> >> - def set_defn(self, meta, name): >> + def set_defn(self, meta: str, name: str) -> None: >> self.defn_meta = meta >> self.defn_name = name >> >> - def next_line(self): >> + def next_line(self: T) -> T: >> info = copy.copy(self) >> info.line += 1 >> return info >> >> - def loc(self): >> + def loc(self) -> str: >> if self.fname is None: >> return sys.argv[0] >> ret = self.fname >> @@ -49,13 +54,13 @@ def loc(self): >> ret += ':%d' % self.line >> return ret >> >> - def in_defn(self): >> + def in_defn(self) -> str: >> if self.defn_name: >> return "%s: In %s '%s':\n" % (self.fname, >> self.defn_meta, self.defn_name) >> return '' >> >> - def include_path(self): >> + def include_path(self) -> str: >> ret = '' >> parent = self.parent >> while parent: >> @@ -63,5 +68,5 @@ def include_path(self): >> parent = parent.parent >> return ret >> >> - def __str__(self): >> + def __str__(self) -> str: >> return self.include_path() + self.in_defn() + self.loc()