Fix handling of immediate child workflow cancellation #276
Description
Currently when a single decision batch contains StartChildWorkflowExecution and RequestCancelExternalWorkflowExecution the cancellation fails and the child is started.
The expected behaviour is that the child is immediately cancelled ideally by writing the following events into the history:
RequestCancelExternalWorkflowExecutionInitiatedExternalWorkflowExecutionCancelRequestedChildWorkflowExecutionCanceled
Here is an example history which shows the current broken behaviour:
1 2020-04-05T16:34:53-07:00 EventTypeWorkflowExecutionStarted {WorkflowType:{Name:TestWorkflow_execute}, ParentInitiatedEventId:0,
TaskList:{Name:WorkflowTest-testChildWorkflowCancellation-49a80f10-fb1d-49c6-a9f1-282b2e31f460,
Kind:TaskListKindNormal}, Input:["WAIT_CANCELLATION_REQUESTED"],
ExecutionStartToCloseTimeoutSeconds:30, TaskStartToCloseTimeoutSeconds:5,
Initiator:ContinueAsNewInitiatorDecider, ContinuedFailureDetails:[], LastCompletionResult:[],
OriginalExecutionRunId:f2bc6299-a8b3-4996-9c0c-f4414f1a79bd, Identity:unknown-mac,
FirstExecutionRunId:f2bc6299-a8b3-4996-9c0c-f4414f1a79bd, Attempt:0, ExpirationTimestamp:0,
FirstDecisionTaskBackoffSeconds:0}
2 2020-04-05T16:34:53-07:00 EventTypeDecisionTaskScheduled {TaskList:{Name:WorkflowTest-testChildWorkflowCancellation-49a80f10-fb1d-49c6-a9f1-282b2e31f460,
Kind:TaskListKindNormal}, StartToCloseTimeoutSeconds:5, Attempt:0}
3 2020-04-05T16:34:53-07:00 EventTypeWorkflowExecutionCancelRequested {ExternalInitiatedEventId:0,
Identity:unknown-mac}
4 2020-04-05T16:34:53-07:00 EventTypeDecisionTaskStarted {ScheduledEventId:2, Identity:unknown-mac,
RequestId:15e68a7d-672f-4e20-937c-3f3b3c646734}
5 2020-04-05T16:34:53-07:00 EventTypeDecisionTaskCompleted {ExecutionContext:[],
ScheduledEventId:2,
StartedEventId:4,
Identity:unknown-mac}
6 2020-04-05T16:34:53-07:00 EventTypeStartChildWorkflowExecutionInitiated {WorkflowId:68563d49-3289-3c7a-9a39-e0e0d21d39bf,
WorkflowType:{Name:TestChildWorkflow_execute},
TaskList:{Name:WorkflowTest-testChildWorkflowCancellation-49a80f10-fb1d-49c6-a9f1-282b2e31f460,
Kind:TaskListKindNormal}, Input:[], ExecutionStartToCloseTimeoutSeconds:30,
TaskStartToCloseTimeoutSeconds:10, ParentClosePolicy:ParentClosePolicyAbandon,
Control:[], DecisionTaskCompletedEventId:5,
WorkflowIdReusePolicy:WorkflowIdReusePolicyAllowDuplicateFailedOnly}
7 2020-04-05T16:34:53-07:00 EventTypeRequestCancelExternalWorkflowExecutionInitiated {DecisionTaskCompletedEventId:5,
WorkflowExecution:{WorkflowId:68563d49-3289-3c7a-9a39-e0e0d21d39bf},
Control:[], ChildWorkflowOnly:true}
8 2020-04-05T16:34:53-07:00 EventTypeRequestCancelExternalWorkflowExecutionFailed {Cause:CancelExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution,
DecisionTaskCompletedEventId:-23, Namespace:UnitTest,
WorkflowExecution:{WorkflowId:68563d49-3289-3c7a-9a39-e0e0d21d39bf}, InitiatedEventId:7,
Control:[]}
9 2020-04-05T16:34:53-07:00 EventTypeDecisionTaskScheduled {TaskList:{Name:unknown-mac:83e37a46-43b3-40e0-bbc0-a40f27208f84,
Kind:TaskListKindNormal}, StartToCloseTimeoutSeconds:5,
Attempt:0}
10 2020-04-05T16:34:53-07:00 EventTypeChildWorkflowExecutionStarted {InitiatedEventId:6,
WorkflowExecution:{WorkflowId:68563d49-3289-3c7a-9a39-e0e0d21d39bf,
RunId:c4b71487-52e5-4984-a47d-105fa4478979},
WorkflowType:{Name:TestChildWorkflow_execute}}
11 2020-04-05T16:34:53-07:00 EventTypeDecisionTaskStarted {ScheduledEventId:9,
Identity:83e37a46-43b3-40e0-bbc0-a40f27208f84,
RequestId:995457b0-b937-4333-b5c1-2b6083bee769}
12 2020-04-05T16:34:53-07:00 EventTypeDecisionTaskCompleted {ExecutionContext:[],
ScheduledEventId:9,
StartedEventId:11,
Identity:unknown-mac}
13 2020-04-05T16:35:23-07:00 EventTypeWorkflowExecutionTimedOut {TimeoutType:TimeoutTypeStartToClose}