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 5F588CCF9E3 for ; Tue, 11 Nov 2025 08:33:36 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vIjoG-0004wm-0T; Tue, 11 Nov 2025 03:33:04 -0500 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 1vIjoD-0004uF-K1 for qemu-devel@nongnu.org; Tue, 11 Nov 2025 03:33:01 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vIjoB-0006wH-MM for qemu-devel@nongnu.org; Tue, 11 Nov 2025 03:33:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1762849978; 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; bh=EXKyOcunz6ZnbsAMAB4Cp9D/S+X8ZcSfzrRflrJkOV8=; b=MOW4tefWXk45dnB1XOyFKuSVuKcd2ul5jwSyFFYkcxGUhcVxlpeAVMNaEa8Cdzq5eASx0m Yz/Bgvi70HmzAtvdyLRi/SiW4RrymGoUWDq0tgDFczrrnnOdyRGUk9IVvwBxMKFSZJPLA6 ckydrlbFcYm9sOXD7wtyNPaoXnPQdxk= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-677-8MQ2_IT_P7m3a9QIp-XArw-1; Tue, 11 Nov 2025 03:32:55 -0500 X-MC-Unique: 8MQ2_IT_P7m3a9QIp-XArw-1 X-Mimecast-MFC-AGG-ID: 8MQ2_IT_P7m3a9QIp-XArw_1762849974 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2659E195606E; Tue, 11 Nov 2025 08:32:54 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.18]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7804C180057F; Tue, 11 Nov 2025 08:32:53 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id E237921E6A27; Tue, 11 Nov 2025 09:32:50 +0100 (CET) From: Markus Armbruster To: qemu-devel@nongnu.org Cc: Kevin Wolf , =?utf-8?Q?Daniel_P=2E_Berrang=C3=A9?= , Peter Maydell , =?utf-8?Q?Alex_Benn=C3=A9e?= , Paolo Bonzini , devel@lists.libvirt.org Subject: Does our interface compatibility promise cover defaults? Date: Tue, 11 Nov 2025 09:32:50 +0100 Message-ID: <875xbhdl59.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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, 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_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-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 >From about/deprecated.rst: In general features are intended to be supported indefinitely once introduced into QEMU. In the event that a feature needs to be removed, it will be listed in this section. The feature will remain functional for the release in which it was deprecated and one further release. After these two releases, the feature is liable to be removed. Deprecated features may also generate warnings on the console when QEMU starts up, or if activated via a monitor command, however, this is not a mandatory requirement. This obviously applies to syntax and semantics of our external interface. Does it apply to default values there? If no: does this mean we can change defaults without notice? If yes: does this mean any change of defaults needs notice in about/deprecated.rst and the grace period? Note that changing a default is a silent change, like changing semantics / behavior, unlike changing syntax.