...or an array of dictionaries. Although we have to cater to
existing commands, returning a non-dictionary means the command
is not extensible (no new name/value pairs can be added if more
information must be returned in parallel). By making the
whitelist explicit, any new command that falls foul of this
practice will have to be self-documenting, which will encourage
developers to either justify the action or rework the design to
use a dictionary after all.
It's a little bit sloppy that we share a single whitelist among
three clients (it's too permissive for each). If this is a
problem, a future patch could tighten things by having the
generator take the whitelist as an argument (as in
scripts/qapi-commands.py --legacy-returns=...), or by having
the generator output C code that requires explicit use of the
whitelist (as in:
#ifndef FROBNICATE_LEGACY_RETURN_OK
# error Command 'frobnicate' should return a dictionary
#endif
then having the callers define appropriate macros). But until
we need such fine-grained separation (if ever), this patch does
the job just fine.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Demonstrate that the qapi generator silently parses confusing
types, which may cause other errors later on. Later patches
will update the expected results as the generator is made stricter.
Most of the new tests focus on blatant errors. But
returns-whitelist is a case where we have historically allowed
returning something other than a JSON object from particular
commands; we have to keep that behavior to avoid breaking clients,
but it would be nicer to avoid adding such commands in the future,
because any return that is not an (array of) object cannot be
easily extended if future qemu wants to return additional
information. The QMP protocol already documents that clients
should ignore unknown dictionary keys, but does not require
clients to have to handle more than one type of JSON object.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
