-blockdev and blockdev-add silently ignore empty objects and arrays in
their argument. That's because qmp_blockdev_add() converts the
argument to a flat QDict, and qdict_flatten() eats empty QDict and
QList members. For instance, we ignore an empty BlockdevOptions
member @cache. No real harm, as absent means the same as empty there.
Thus, the flaw puts an artificial restriction on the QAPI schema: we
can't have potentially empty objects and arrays within
BlockdevOptions, except when they're optional and "empty" has the same
meaning as "absent".
Our QAPI schema satisfies this restriction (I checked), but it's a
trap for the unwary, and a temptation to employ awkward workarounds
for the wary. Let's get rid of it.
Change qdict_flatten() and qdict_crumple() to treat empty dictionaries
and lists exactly like scalars.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2860b2b2cb