On 04/11/2013 09:17 PM, Wenchao Xia wrote:
Hmm, as I typed that, I did another search of qemu-schema.json - we have
the type 'ImageInfo' defined, but none of the existing 'command's ever
call out the use of that type. Is it a type we are only using
internally to date, and where this is the first QMP command that would
actually expose SnapshotInfo or ImageInfo to a management app? Then
maybe we _CAN_ modify SnapshotInfo, clean up all the internal code, and
provide a saner type for the first time that QMP can actually use it.
IIRC, it's being used by qemu-img. As it's not trivial to determine if
the field has users and as what goes in the schema is to be considered
stable,
it's better to keep the field. Instead, we could add a better field and
deprecate the current one.
I remember there is a patch laster year made "qemu-img info" dump out
json strings, where vm-clock-sec is dumped out.
Ah, so it's not QMP exposing it, but qemu-info in JSON mode. Still,
changing that output to delete a field might break existing tools;
adding a field might be safer, but then you'd have redundant information
in the old style for old tools, as well as the added field.