From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49454) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhD9z-0004qu-CS for qemu-devel@nongnu.org; Mon, 05 May 2014 03:18:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WhD9t-000282-24 for qemu-devel@nongnu.org; Mon, 05 May 2014 03:17:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55039) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhD9s-00027u-R9 for qemu-devel@nongnu.org; Mon, 05 May 2014 03:17:52 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s457Hp9H020548 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Mon, 5 May 2014 03:17:51 -0400 From: Fam Zheng Date: Mon, 5 May 2014 15:17:59 +0800 Message-Id: <1399274279-20165-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH] qapi: Document optional arguments' backwards compatibility List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Markus Armbruster , Luiz Capitulino Signed-off-by: Fam Zheng --- docs/qapi-code-gen.txt | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index d78921f..d7b19ab 100644 --- a/docs/qapi-code-gen.txt +++ b/docs/qapi-code-gen.txt @@ -51,8 +51,10 @@ example of a complex type is: The use of '*' as a prefix to the name means the member is optional. Optional members should always be added to the end of the dictionary to preserve -backwards compatibility. - +backwards compatibility. Even there is no strict restriction for default values +of those optional arguments between QEMU's versions, the backwards +compatibility should be preserved by keeping the user visible behavior +unchanged. A complex type definition can specify another complex type as its base. In this case, the fields of the base type are included as top-level fields -- 1.9.2