Nexus cancellation types: handle NexusOperationCancelRequestCompleted, NexusOperationCancelRequestFailed
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NexusOperationCancelRequestCompleted & WAIT_REQUESTEDNexusOperationCancelRequestCompleted, NexusOperationCancelRequestFailed
dandavison
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Aug 15, 2025
| TimedOut --(NexusOperationCancelRequestCompleted(NexusOperationCancelRequestCompletedEventAttributes))--> TimedOut; | ||
| Completed --(NexusOperationCancelRequestFailed(NexusOperationCancelRequestFailedEventAttributes))--> Completed; | ||
| Failed --(NexusOperationCancelRequestFailed(NexusOperationCancelRequestFailedEventAttributes))--> Failed; | ||
| TimedOut --(NexusOperationCancelRequestFailed(NexusOperationCancelRequestFailedEventAttributes))--> TimedOut; |
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[I haven't yet proved that I can make these transitions happen in tests.]
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I think that's fine. Some of these "if it happens just ignore" transitions can be like that.
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Aug 18, 2025
| TimedOut --(NexusOperationCancelRequestCompleted(NexusOperationCancelRequestCompletedEventAttributes))--> TimedOut; | ||
| Completed --(NexusOperationCancelRequestFailed(NexusOperationCancelRequestFailedEventAttributes))--> Completed; | ||
| Failed --(NexusOperationCancelRequestFailed(NexusOperationCancelRequestFailedEventAttributes))--> Failed; | ||
| TimedOut --(NexusOperationCancelRequestFailed(NexusOperationCancelRequestFailedEventAttributes))--> TimedOut; |
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I think that's fine. Some of these "if it happens just ignore" transitions can be like that.
These events are written by the caller server on receiving a response from the nexus cancel handler. The only cancellation type that is sensitive to them is WaitRequested: when that is in effect, these events cause an activation job to be emitted that resolves the nexus operation future. The fsm macro is modified to allow the same union type to be constructed twice, since Started -> Started|Cancelled is now caused by two different inputs.
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Fixes #911
Handle new events
NexusOperationCancelRequestCompletedandNexusOperationCancelRequestFailed.These events are written by the caller server when it receives the result of the nexus op cancel request. The only cancellation type that is sensitive to these is
WaitRequested. From lang's point of view, underWaitRequested, those events cause the nexus operation handle future to be resolved as cancelled / failed respectively. Thus lang can choose to see the cancellation when the cancel handler has successfully returned, but prior to any cancellation of the operation itself. In the case of cancel handler failure, that failure will be thrown out of the operation handle future and the user will not be able to use the handle to access any terminal state that the operation might reach.Also modifies the
fsm!macro to allow the same union type to be constructed twice, sinceStarted -> Started|Cancelledis now caused by two different inputs.The real test coverage for this PR is coming in temporalio/sdk-python#981 [Draft].