From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:50230) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SCVOk-0001g9-Db for qemu-devel@nongnu.org; Tue, 27 Mar 2012 08:21:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SCVOe-0000Mh-6C for qemu-devel@nongnu.org; Tue, 27 Mar 2012 08:21:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41310) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SCVOd-0000MK-Ua for qemu-devel@nongnu.org; Tue, 27 Mar 2012 08:21:08 -0400 From: Luiz Capitulino Date: Tue, 27 Mar 2012 09:20:51 -0300 Message-Id: <1332850851-4059-14-git-send-email-lcapitulino@redhat.com> In-Reply-To: <1332850851-4059-1-git-send-email-lcapitulino@redhat.com> References: <1332850851-4059-1-git-send-email-lcapitulino@redhat.com> Subject: [Qemu-devel] [PATCH 13/13] qmp: document strict parsing List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: aliguori@us.ibm.com Cc: Paolo Bonzini , qemu-devel@nongnu.org From: Paolo Bonzini Signed-off-by: Paolo Bonzini Signed-off-by: Luiz Capitulino --- QMP/qmp-spec.txt | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/QMP/qmp-spec.txt b/QMP/qmp-spec.txt index 9d30a8c..1ba916c 100644 --- a/QMP/qmp-spec.txt +++ b/QMP/qmp-spec.txt @@ -209,13 +209,27 @@ incompatible way are disabled by default and will be advertised by the capabilities array (section '2.2 Server Greeting'). Thus, Clients can check that array and enable the capabilities they support. -Additionally, Clients must not assume any particular: - -- Size of json-objects or length of json-arrays +The QMP Server performs a type check on the arguments to a command. It +generates an error if a value does not have the expected type for its +key, or if it does not understand a key that the Client included. The +strictness of the Server catches wrong assumptions of Clients about +the Server's schema. Clients can assume that, when such validation +errors occur, they will be reported before the command generated any +side effect. + +However, Clients must not assume any particular: + +- Length of json-arrays +- Size of json-objects; in particular, future versions of QEMU may add + new keys and Clients should be able to ignore them. - Order of json-object members or json-array elements - Amount of errors generated by a command, that is, new errors can be added to any existing command in newer versions of the Server +Of course, the Server does guarantee to send valid JSON. But apart from +this, a Client should be "conservative in what they send, and liberal in +what they accept". + 6. Downstream extension of QMP ------------------------------ -- 1.7.9.2.384.g4a92a