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,SPF_HELO_NONE,SPF_PASS,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 2B739C433F5 for ; Thu, 16 Sep 2021 15:55:01 +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 A277461212 for ; Thu, 16 Sep 2021 15:55:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A277461212 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:41708 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mQtj1-0003bg-TD for qemu-devel@archiver.kernel.org; Thu, 16 Sep 2021 11:54:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43586) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mQtTr-0001S9-AM for qemu-devel@nongnu.org; Thu, 16 Sep 2021 11:39:19 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:59019) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mQtTp-0001BI-84 for qemu-devel@nongnu.org; Thu, 16 Sep 2021 11:39:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631806756; h=from:from:reply-to: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=aGZnR418PGCFlYSm2qeQC+EAo0GuxrqqM+EMUQWr4mc=; b=TNLWj+LHpMFtUbOYicwl5Snz8msUaTXpRGz6azNwE7OWCkrJqqfk4BqAD2qwl2bmc5Erii NZ7MrzVlkBi4/PCPtlovTxywklxo2xnQtx9Uzuw0P6W83qK/EkZkstirsd/ZACPaX//Ts7 WHPceDb3yYY/lXr4VyZHBMh6Pk7QU3U= 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-597-QxiB_-riPJi73xAEpoH2GA-1; Thu, 16 Sep 2021 11:39:11 -0400 X-MC-Unique: QxiB_-riPJi73xAEpoH2GA-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 44EE810247A6; Thu, 16 Sep 2021 15:39:10 +0000 (UTC) Received: from redhat.com (unknown [10.39.195.97]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 809555C1CF; Thu, 16 Sep 2021 15:39:08 +0000 (UTC) Date: Thu, 16 Sep 2021 16:39:06 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: John Snow Subject: Re: [PATCH v3 1/1] python: Update for pylint 2.10 Message-ID: References: <20210915154031.321592-1-jsnow@redhat.com> <20210915154031.321592-2-jsnow@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.392, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Peter Maydell , Eduardo Habkost , qemu-devel , G S Niteesh Babu , Cleber Rosa , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Sep 16, 2021 at 09:42:30AM -0400, John Snow wrote: > On Thu, Sep 16, 2021 at 8:59 AM Daniel P. Berrangé > wrote: > > > On Wed, Sep 15, 2021 at 11:40:31AM -0400, John Snow wrote: > > > A few new annoyances. Of note is the new warning for an unspecified > > > encoding when opening a text file, which actually does indicate a > > > potentially real problem; see > > > https://www.python.org/dev/peps/pep-0597/#motivation > > > > > > Use LC_CTYPE to determine an encoding to use for interpreting QEMU's > > > terminal output. Note that Python states: "language code and encoding > > > may be None if their values cannot be determined" -- use a platform > > > default as a backup. > > > > > > Signed-off-by: John Snow > > > --- > > > python/qemu/machine/machine.py | 9 ++++++++- > > > python/setup.cfg | 1 + > > > 2 files changed, 9 insertions(+), 1 deletion(-) > > > > > > diff --git a/python/qemu/machine/machine.py > > b/python/qemu/machine/machine.py > > > index a7081b1845..51b6e79a13 100644 > > > --- a/python/qemu/machine/machine.py > > > +++ b/python/qemu/machine/machine.py > > > @@ -19,6 +19,7 @@ > > > > > > import errno > > > from itertools import chain > > > +import locale > > > import logging > > > import os > > > import shutil > > > @@ -290,8 +291,14 @@ def get_pid(self) -> Optional[int]: > > > return self._subp.pid > > > > > > def _load_io_log(self) -> None: > > > + # Assume that the output encoding of QEMU's terminal output > > > + # is defined by our locale. If indeterminate, use a platform > > default. > > > + _, encoding = locale.getlocale() > > > + if encoding is None: > > > + encoding = locale.getpreferredencoding(do_setlocale=False) > > > > Do we really need this getpreferredencoding ? IIUC, this is a sign > > that the application is buggy by not calling > > > > locale.setlocale(locale.LC_ALL, '') > > > > during its main() method, which I think we can just delegate to the > > code in question to fix. Missing setlocale will affect everything > > they run, so doing workarounds in only 1 place is not worth it IMHO > > > > > I genuinely don't know! (And, I try to keep the Python code free from > assuming Linux as much as I can help it.) > > Python's getlocale documentation states: "language code and encoding may be > None if their values cannot be determined." > https://docs.python.org/3/library/locale.html#locale.getlocale > > But it is quiet as to the circumstances under which this may happen. > Browsing the cpython source code, (3.9ish): > > ``` > def getlocale(category=LC_CTYPE): > localename = _setlocale(category) > if category == LC_ALL and ';' in localename: > raise TypeError('category LC_ALL is not supported') > return _parse_localename(localename) > ``` > _setlocale is ultimately a call to (I think) _localemodule.c's > PyLocale_setlocale(PyObject *self, PyObject *args) C function. > It calls `result = setlocale(category, locale)` where the category is going > to be LC_CTYPE, so this should be equivalent to locale(3) (LC_CTYPE, NULL). > > locale(3) says that "The return value is NULL if the request cannot be > honored." > > Python parses that string according to _parse_localename, which in turn > calls normalize(localename). > Normalization looks quite involved, but has a fallback of returning the > string verbatim. If the normalized locale string is "C", we return the > tuple (None, None)! > > So I figured there was a non-zero chance that we'd see a value of `None` > here. > > Source code is in cpython/Lib/locale.py and cpython/Modules/_localemodule.c > if you want to nose around yourself. > > I also have no idea how this will all shake out on Windows, so I decided to > add the fallback here just in case. (Does the Python package work on > Windows? I don't know, but I avoid assuming it won't EVER run there... > Certainly, I have an interest in having the QMP packages I am building work > on all platforms.) > > Thoughts? Well this machine.py is using UNIX domain sockets and FD passing, so Windows is out of the question. I'd be inclined to just keep it simple unless someone reports a real bug with it. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|