From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59593) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXPjM-0005QH-K2 for qemu-devel@nongnu.org; Mon, 25 Jun 2018 07:32:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fXPjI-0003x4-2R for qemu-devel@nongnu.org; Mon, 25 Jun 2018 07:32:24 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:37602 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fXPjH-0003ui-Uj for qemu-devel@nongnu.org; Mon, 25 Jun 2018 07:32:20 -0400 From: Markus Armbruster References: <20180601153922.11590-1-ricardo.perez_blanco@nokia.com> <20180608094101.GG2671@work-vm> <0cc71e01-7015-8f8b-6988-d3b411d3b28c@suse.de> <87y3fky231.fsf@dusky.pond.sub.org> Date: Mon, 25 Jun 2018 13:32:17 +0200 In-Reply-To: <87y3fky231.fsf@dusky.pond.sub.org> (Markus Armbruster's message of "Tue, 12 Jun 2018 08:02:26 +0200") Message-ID: <87h8lrumny.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2] Show values and description when using "qom-list" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: Andreas =?utf-8?Q?F=C3=A4rber?= , Ricardo Perez Blanco , qemu-devel , Dongli Zhang Markus Armbruster writes: > Andreas F=C3=A4rber writes: > >> Am 08.06.2018 um 11:41 schrieb Dr. David Alan Gilbert: >>> * Andreas F=C3=A4rber (afaerber@suse.de) wrote: >>>> Am 01.06.2018 um 17:39 schrieb Ricardo Perez Blanco: >>>>> For debugging purposes it is very useful to: >>>>> - See the description of the field. This information is already fill= ed >>>>> in but not shown in "qom-list" command. >>>> >>>> No objection on this part. >>>> >>>>> - Display value of the field. >>>> >>>> That is by definition the qom-get operation, not qom-list. Just like t= he >>>> ls command does not show file contents, there's cat etc. for that. For >>>> debugging purposes we had a qom-tree (?) command that would combine >>>> both. >>> >>> I'm not too bothered about distinguishing between the two commands; >>> but it would be nice > > When an HMP and QMP both have a command with the same name, they should > do the same. > > HMP may add convenience features that aren't wanted in QMP, but I feel > extending an operation to list objects to also show their contents goes > beyond that. If we want an HMP command that does both, it should be > named differently. Perhaps that might even be more appropriate for HMP > than low-level commands qom-list and qom-get, but I leave that to the > HMP maintainer to decide. > >>> - one reason I'm not too bothered is because we've >>> failed to get a qom-get in multiple years of trying. > > We clearly haven't tried hard enough. > > If we can figure out how to show values in qom-list, surely we can > figure out how to show them in qom-get. > >>>> There might be unmerged patches on qemu-devel related to display >>>> of certain data types. >>>=20 >>> Which ones? >> >> My original qom-info series needed StringOutputVisitor changes for enums >> (test case: rtc) that did not get accepted immediately and thus some >> part of HMP qom-info/qom-get got stuck due to risking assertions for >> qom-info / otherwise; QMP was not affected IIRC. > > Here's the last try I can find: > [PATCH v2] qom: Implement qom-get HMP command > Message-Id: <1473157086-12062-1-git-send-email-dgilbert@redhat.com> > https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg01041.html Stalled on output format and consistency with qom-set. I wrote back then "We can take qom-get as is and improve its output later." I'd like to encourage you to dust it off. Perfect's the enemy of good. Wanted improvements include: * Prettier output format. I'd suggest creating a keyval variant of the output visitor. * Make qom-set input format consistent by switching to the matching input visitor. > Its v1 tries a different approach: > [PATCH 0/2] qom-get [for 2.8] > Message-Id: <1472117833-10236-1-git-send-email-dgilbert@redhat.com> > Unfortunately the mailing list archive doesn't show the full thread, so > you get to follow three links: > https://lists.gnu.org/archive/html/qemu-devel/2016-08/msg03815.html > https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg04261.html > https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg04267.html This one stalled on string visitor limitations. You didn't feel like addressing them just to get qom-get working. Understandable.