From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:45799) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SApky-00050Y-KT for qemu-devel@nongnu.org; Thu, 22 Mar 2012 17:41:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SApkv-0001i4-H4 for qemu-devel@nongnu.org; Thu, 22 Mar 2012 17:41:16 -0400 Received: from mail-gy0-f173.google.com ([209.85.160.173]:44904) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SApkv-0001hx-9s for qemu-devel@nongnu.org; Thu, 22 Mar 2012 17:41:13 -0400 Received: by ghrr14 with SMTP id r14so2695543ghr.4 for ; Thu, 22 Mar 2012 14:41:11 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Thu, 22 Mar 2012 22:39:39 +0100 Message-Id: <1332452379-22024-1-git-send-email-pbonzini@redhat.com> In-Reply-To: <1332417072-20329-1-git-send-email-pbonzini@redhat.com> References: <1332417072-20329-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 11/10] qmp: document strict parsing List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: eblake@redhat.com, mdroth@linux.vnet.ibm.com, anthony@codemonkey.ws, lcapitulino@redhat.com Signed-off-by: Paolo Bonzini --- QMP/qmp-spec.txt | 20 +++++++++++++++++--- 1 files 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 ------------------------------ -- 1.7.9.1