What causes “The required feature ' refId'

问题:

I'm using REDHAWK 2.0.4 on CentOS 7

I'm trying to follow the tutorial here: https://www.youtube.com/watch?v=SttCsAIQtSA At 11:14 they add a device dependency to the xml file:

<usesdevicedependencies>
  <usesdevice id="device_connection">
    <propertyref refid="DCE:cdc5ee18-7ceb-4ae6-bf4c-31f983179b4d"
                 value="chirp"/>
  </usesdevice>
<usesdevicedependencies>

And this

<connectinterface id="device_connection_1">
  <usesport>
    <usesidentifier>dataFloat_out</usesidentifier>
    <deviceusedbyapplication usesrefid="device_connection"/>
  </usesport>
  <providesport>
    <providesidentifier>dataFloat_In</providesidentifier>
    <componentinstationref refid="TuneFilterDecimate_1"/>
  </providesport>
</connectinterface>

When I do the same thing, I'm given the error from the title:

The required feature ' refId' of 'Device Used By Application' must be set

I thought "DeviceUsedByApplication" used "usesrefid", maybe this error is caused by something else?

回答1:

The error being reported by the IDE is actually incorrect. This is a bug that was fixed in the recent 2.0.5 release. See the release notes (https://github.com/redhawksdr/redhawk/releases/tag/2.0.5):

Adding a FrontEnd Uses Device to a Waveform no longer causes an error when saving the Waveform

回答2:

I got message from the developer and they said that the issue has been confirmed in 2.0.4.

Just to confirm, the issue that you experienced in 2.0.4 has actually been
there a while, but it seems like it's now getting checked. Adding the refid to 
the devicesusedbyapplication will get rid of the message, but as you 
experienced, it has no bearing on whether or not it breaks anything. With any 
luck it'll be fixed soon. Until then though, it can be ignored or mitigated as you did.