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 07FC1CDB47E for ; Wed, 18 Oct 2023 14:34:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qt7cb-0008SQ-7V; Wed, 18 Oct 2023 10:34:05 -0400 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 1qt7cX-0008Mx-37; Wed, 18 Oct 2023 10:34:01 -0400 Received: from mx.treblig.org ([2a00:1098:5b::1]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qt7cV-0008VO-1X; Wed, 18 Oct 2023 10:34:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=treblig.org ; s=bytemarkmx; h=In-Reply-To:Content-Transfer-Encoding:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=o4av8QNV4tVroMlLYxeUZim18cwUW3pZBcX7BnarRVk=; b=cobQLwKbjKOkz48O6+5FKoT/Ah fG+Iq7qSscCbxGnhyx8hAWM+s59dncbmiUUNJ31KFb7+77n5z2tPq+JdhLSeCF2Gn1PRh7ugOeXqK TxtO7EIAxhdh5kI/2VWtzu6Lsq8LGCiBPkRoLuO4pa5EY6vDfXEDA0nA6C8daZgFS/Ku4ep7CDU62 R3oeqx8cr+HP+r3qBKRY0Rl8A7cLaIxyeVJD+A9cOzDcwfol8EorlDkBQALl4BfmzZKZI/MGI7rGe vbkdLAJBDqlvlot/W96Ag460Ero2ERekqIQsDLJ1T5Iydh+xpS6KKyWoyxIPxnMvr4HxwEqJHDhWo WceXq33g==; Received: from dg by mx.treblig.org with local (Exim 4.96) (envelope-from ) id 1qt7cP-005Hdo-1v; Wed, 18 Oct 2023 14:33:53 +0000 Date: Wed, 18 Oct 2023 14:33:53 +0000 From: "Dr. David Alan Gilbert" To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Cc: Markus Armbruster , "Michael S. Tsirkin" , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, qemu-devel@nongnu.org, eblake@redhat.com, eduardo@habkost.net, pbonzini@redhat.com, hreitz@redhat.com, kwolf@redhat.com, raphael.norwitz@nutanix.com, yc-core@yandex-team.ru, den-plotnikov@yandex-team.ru, daniil.tatianin@yandex.ru Subject: Re: [PATCH 4/4] qapi: introduce CONFIG_READ event Message-ID: References: <20231006202045.1161543-5-vsementsov@yandex-team.ru> <87sf692t0i.fsf@pond.sub.org> <877cnkzasr.fsf@pond.sub.org> <878r80tdyd.fsf@pond.sub.org> <20231018064912-mutt-send-email-mst@kernel.org> <87o7gwp29r.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Chocolate: 70 percent or better cocoa solids preferably X-Operating-System: Linux/6.1.0-12-amd64 (x86_64) X-Uptime: 14:32:53 up 32 days, 17:31, 1 user, load average: 0.03, 0.01, 0.00 User-Agent: Mutt/2.2.12 (2023-09-09) Received-SPF: pass client-ip=2a00:1098:5b::1; envelope-from=dg@treblig.org; helo=mx.treblig.org X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: 2.1.29 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 * Daniel P. Berrangé (berrange@redhat.com) wrote: > On Wed, Oct 18, 2023 at 02:02:08PM +0200, Markus Armbruster wrote: > > Daniel P. Berrangé writes: > > > > > On Wed, Oct 18, 2023 at 06:51:41AM -0400, Michael S. Tsirkin wrote: > > >> On Wed, Oct 18, 2023 at 12:36:10PM +0200, Markus Armbruster wrote: > > >> > > x- seems safer for management tool that doesn't know about "unstable" properties.. > > >> > > > >> > Easy, traditional, and unreliable :) > > >> > > >> > > But on the other hand, changing from x- to no-prefix is already > > >> > > done when the feature is stable, and thouse who use it already > > >> > > use the latest version of interface, so, removing the prefix is > > >> > > just extra work. > > >> > > > >> > Exactly. > > >> > > > >> > > >> I think "x-" is still better for command line use of properties - we > > >> don't have an API to mark things unstable there, do we? > > > > > > Personally I like to see "x-" prefix present *everywhere* there is > > > an unstable feature, and consider the need to rename when declaring > > > it stable to be good thing as it sets an easily identifiable line > > > in the sand and is self-evident to outside observers. > > > > > > The self-documenting nature of the "x-" prefer is what makes it most > > > compelling to me. A patch submission, or command line invokation or > > > an example QMP command, or a bug report, that exhibit an 'x-' prefix > > > are an immediate red flag to anyone who sees them. > > > > Except when it isn't, like in "x-origin". > > > > > If someone sees a QMP comamnd / a typical giant QEMU command line, > > > they are never going to go look at the QAPI schema to check whether > > > any feature used had an 'unstable' marker. The 'unstable' marker > > > might as well not exist in most cases. > > > > > > IOW, having the 'unstable' flag in the QAPI schema is great for machine > > > introspection, but it isn't a substitute for having an 'x-' prefix used > > > for the benefit of humans IMHO. > > > > I'm not sure there's disagreement. Quoting myself: > > > > The "x-" can remind humans "this is unstable" better than a feature > > flag can (for machines, it's the other way round). > > > > CLI and HMP are for humans. We continue to use "x-" there. > > > > QMP is for machines. The feature flag is the sole source of truth. > > Additional use of "x-" is fine, but not required. > > I guess we have different defintions of "for humans" in this context. > I consider QMP data still relevant for humans, because humans are > reviewing patches to libvirt that add usage of QMP features, or > triaging bug reports that include examples of usage, and in both > cases it is pretty relevant to make unstable features stand out to > the human via the x- prefix IMHO. Using x- for events makes sense to me; the semantics of events can be quite subtle; often you don't find out how broken they are until you wire them through libvirt and up the stack; so it's not impossible you might need to change it - but then without the x- the semantics (rather than existence) of the event is carved in stone. Dave > With 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 :| > -- -----Open up your eyes, open up your mind, open up your code ------- / Dr. David Alan Gilbert | Running GNU/Linux | Happy \ \ dave @ treblig.org | | In Hex / \ _________________________|_____ http://www.treblig.org |_______/