Unhandled error in Deferred

[maasuser1]

3.4.1-14343-g.a552d2522 from Snap.

rackd.log

```
2024-03-22 15:23:08 twisted.internet.defer: [critical] Unhandled error in Deferred: 2024-03-22 15:23:08 twisted.internet.defer: [critical] Traceback (most recent call last):
        --- <exception caught here> --- File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 857, in _runCallbacks
            current.result = callback( # type: ignore[misc] File "/snap/maas/34087/lib/python3.10/site-packages/provisioningserver/rpc/common.py", line 149, in _global_intercept_errback failure.raiseException()
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/python/failure.py", line 475, in raiseException raise self.value.with_traceback(self.tb)
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 857, in _runCallbacks
            current.result = callback( # type: ignore[misc]
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/protocols/amp.py", line 1946, in _massageError
            error.trap(RemoteAmpError)
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/python/failure.py", line 451, in trap
            self.raiseException()
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/python/failure.py", line 475, in raiseException raise self.value.with_traceback(self.tb)
        twisted.protocols.amp.UnhandledCommand: (b'UNHANDLED', 'Unknown Error [maas:pid=192123:cmd=ReportNeighbours:ask=45]')
2024-03-22 15:23:08 twisted.internet.defer: [critical] Unhandled error in Deferred:
2024-03-22 15:23:08 twisted.internet.defer: [critical]
        Traceback (most recent call last):
        --- <exception caught here> ---
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 857, in _runCallbacks
            current.result = callback( # type: ignore[misc]
          File "/snap/maas/34087/lib/python3.10/site-packages/provisioningserver/rpc/common.py", line 149, in _global_intercept_errback failure.raiseException()
            error.trap(RemoteAmpError) [30/1924]
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/python/failure.py", line 451, in trap
            self.raiseException()
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/python/failure.py", line 475, in raiseException raise self.value.with_traceback(self.tb)
        twisted.protocols.amp.UnhandledCommand: (b'UNHANDLED', 'Unknown Error [maas:pid=192123:cmd=ReportNeighbours:ask=45]')
2024-03-22 15:23:08 twisted.internet.defer: [critical] Unhandled error in Deferred:
2024-03-22 15:23:08 twisted.internet.defer: [critical]
        Traceback (most recent call last):
        --- <exception caught here> ---
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 857, in _runCallbacks
            current.result = callback( # type: ignore[misc]
          File "/snap/maas/34087/lib/python3.10/site-packages/provisioningserver/rpc/common.py", line 149, in _global_intercept_errback failure.raiseException()
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/python/failure.py", line 475, in raiseException raise self.value.with_traceback(self.tb)
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 857, in _runCallbacks
            current.result = callback( # type: ignore[misc]
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/protocols/amp.py", line 1946, in _massageError
            error.trap(RemoteAmpError)
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/python/failure.py", line 451, in trap
            self.raiseException()
          File "/snap/maas/34087/usr/lib/python3/dist-packages/twisted/python/failure.py", line 475, in raiseException raise self.value.with_traceback(self.tb)
        twisted.protocols.amp.UnhandledCommand: (b'UNHANDLED', 'Unknown Error [maas:pid=192121:cmd=ReportNeighbours:ask=35]')
```

[Jacopo Rota (r00ta)]

twisted.protocols.amp.UnhandledCommand: (b'UNHANDLED',) is usually raised when there is an uncatched exception in the rpc responder. We need to double check if we can statically reproduce this, otherwise we need more information about the reporter's setup

[maasuser1 (maasuser1)]

Thanks r00ta for the explanation!

[Christian Grabowski (cgrabowski)]

Hi there, can you please provide a sos-report from when this happens?

[maasuser1 (maasuser1)]

Hi Christian, I can't. The log was not triggered by a specific user behaviour. I will try if it occurs again.