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gazebosim / gz-transport

Transport library for component communication based on publication/subscription and service calls.
https://gazebosim.org
Apache License 2.0
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`gz service -r` should not require specifying a dummy message if the request type is `Empty` #474

Closed azeey closed 4 months ago

azeey commented 8 months ago

Desired behavior

Currently, gz service -r requires specifying unused: true on requests with an Empty request type. This is not well documented and seems unintuitive. It would be great if the user is able to provide an empty message (gz service -r ' ' ...) or no value at all (gz service -r ...).

Together with #473, it would be nice to be able to run

gz service -s /gazebo/worlds -r --timeout 2000

instead of

gz service -s /gazebo/worlds --reqtype gz.msgs.Empty --reptype gz.msgs.StringMsg_V -r 'unused: true' --timeout 2000

Alternatives considered

n/a

Implementation suggestion

Handle the case where reqtype is Empty so that an empty message is considered valid.

Additional context

n/a

caguero commented 6 months ago

@azeey , What do you think about allowing -r ""? The option -r is configured as a parameter that accepts a value. Not sure if we can make the value optional.

mjcarroll commented 6 months ago

I believe you can add ->expected(0,1) to make it take 0 or 1 arguments

azeey commented 6 months ago

I'm okay with -r "", but if @mjcarroll's suggestion works, that would be even better.

caguero commented 6 months ago

I believe you can add ->expected(0,1) to make it take 0 or 1 arguments

Thanks, it works!