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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D833AC433EF for ; Tue, 26 Oct 2021 08:26:57 +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 7676D60E96 for ; Tue, 26 Oct 2021 08:26:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7676D60E96 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]:46130 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mfHnM-00051j-9s for qemu-devel@archiver.kernel.org; Tue, 26 Oct 2021 04:26:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33546) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfH1y-0003cg-A7 for qemu-devel@nongnu.org; Tue, 26 Oct 2021 03:37:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37412) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfH1u-0004Ul-3l for qemu-devel@nongnu.org; Tue, 26 Oct 2021 03:37:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635233870; 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: in-reply-to:in-reply-to:references:references; bh=XvQuPuvbPDJYhHOMj6ZouCWrdblydTGfu0yE2e/lw4c=; b=WchKaEZ4mJ9Hg8DLj1j6casTH89G2SZTpoPtAGoc7KPT3upxErxIVRbUUairYdurhqONRJ GXUZZRgV1P3/pEYjDsfT3GXp7iAb4nGyqob/D/b2rXcms0vP7Nvj7JNiWnWbCuIyLfTwyM LyKPYhqFcrYvKrVmKS5K51BSdjIHOJQ= 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-395-8oUFGJyZNGOTedFzRS971Q-1; Tue, 26 Oct 2021 03:37:48 -0400 X-MC-Unique: 8oUFGJyZNGOTedFzRS971Q-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D912E18D6A2C; Tue, 26 Oct 2021 07:37:47 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.70]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2204C5DEFB; Tue, 26 Oct 2021 07:37:30 +0000 (UTC) Date: Tue, 26 Oct 2021 09:37:29 +0200 From: Kevin Wolf To: Markus Armbruster Subject: Re: [PATCH 1/9] qapi: New special feature flag "unstable" Message-ID: References: <20211025052532.3859634-1-armbru@redhat.com> <20211025052532.3859634-2-armbru@redhat.com> MIME-Version: 1.0 In-Reply-To: <20211025052532.3859634-2-armbru@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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=-0.001, 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: , Cc: pkrempa@redhat.com, berrange@redhat.com, ehabkost@redhat.com, qemu-block@nongnu.org, quintela@redhat.com, libvir-list@redhat.com, eblake@redhat.com, mdroth@linux.vnet.ibm.com, qemu-devel@nongnu.org, dgilbert@redhat.com, pbonzini@redhat.com, marcandre.lureau@redhat.com, jsnow@redhat.com, libguestfs@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 25.10.2021 um 07:25 hat Markus Armbruster geschrieben: > By convention, names starting with "x-" are experimental. The parts > of external interfaces so named may be withdrawn or changed > incompatibly in future releases. > > Drawback: promoting something from experimental to stable involves a > name change. Client code needs to be updated. > > Moreover, the convention is not universally observed: > > * QOM type "input-barrier" has properties "x-origin", "y-origin". > Looks accidental, but it's ABI since 4.2. > > * QOM types "memory-backend-file", "memory-backend-memfd", > "memory-backend-ram", and "memory-backend-epc" have a property > "x-use-canonical-path-for-ramblock-id" that is documented to be > stable despite its name. > > We could document these exceptions, but documentation helps only > humans. We want to recognize "unstable" in code, like "deprecated". > > Replace the convention by a new special feature flag "unstable". It > will be recognized by the QAPI generator, like the existing feature > flag "deprecated", and unlike regular feature flags. > > This commit updates documentation and prepares tests. The next commit > updates the QAPI schema. The remaining patches update the QAPI > generator and wire up -compat policy checking. > > Signed-off-by: Markus Armbruster Obviously, replacing the old convention gets rid of the old drawbacks, but adds a new one: While using x- makes it very obvious for a human user that this is an unstable feature, a feature flag in the schema will almost certainly go unnoticed in manual use. Kevin