Re: [PATCH 16/21] qapi/migration: Mark that query/set-migrate-parameters support capabilities

[Fabiano Rosas]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Mon, Jun 02, 2025 at 10:38:05PM -0300, Fabiano Rosas wrote:
>> Add a QAPI command feature "capabilities" that can be queried by the
>> client to check that the parameters commands now also support
>> capabilities.
>> 
>> Signed-off-by: Fabiano Rosas <farosas@suse.de>
>> ---
>>  qapi/migration.json | 20 ++++++++++++++++++--
>>  1 file changed, 18 insertions(+), 2 deletions(-)
>> 
>> diff --git a/qapi/migration.json b/qapi/migration.json
>> index 5942622ba7..557a9c523e 100644
>> --- a/qapi/migration.json
>> +++ b/qapi/migration.json
>> @@ -776,6 +776,13 @@
>>  #
>>  # Set various migration parameters.
>>  #
>> +# Features:
>> +#
>> +# @capabilities: Indicates this command supports setting the set of
>> +# parameters previously known as capabilities.  This means this
>> +# command can (and should) be used instead of the depreacated
>> +# @migrate-set-capabilities.
>> +#
>>  # Since: 2.4
>>  #
>>  # .. qmp-example::
>> @@ -785,7 +792,8 @@
>>  #     <- { "return": {} }
>>  ##
>>  { 'command': 'migrate-set-parameters', 'boxed': true,
>> -  'data': 'MigrationParameters' }
>> +  'data': 'MigrationParameters',
>> +  'features': [ 'capabilities' ] }
>>  
>>  ##
>>  # @MigrationParameters:
>> @@ -1110,6 +1118,13 @@
>>  #
>>  # Returns: @MigrationParameters
>>  #
>> +# Features:
>> +#
>> +# @capabilities: Indicates this command supports setting the set of
>> +# parameters previously known as capabilities.  This means this
>> +# command can (and should) be used instead of the depreacated
>> +# @migrate-set-capabilities.
>> +#
>>  # Since: 2.4
>>  #
>>  # .. qmp-example::
>> @@ -1125,7 +1140,8 @@
>>  #        }
>>  ##
>>  { 'command': 'query-migrate-parameters',
>> -  'returns': 'MigrationParameters' }
>> +  'returns': 'MigrationParameters',
>> +  'features': [ 'capabilities' ] }
>>
>
> Adding QAPI "features" is only needed if there is no other viable
> way to detect existence of the feature. In this case, apps can
> trivially detect the feature by querying the QAPI schema and
> identifying that the MigrationParameters struct has gained a
> load of new fields. So IMHO this patch can be dropped.
>

Oh, ok. I was thinking this would be friendlier to the management layer,
but if it's all the same I'll drop it. Same for the other one in patch
19.

Thanks