Test Server: Fix Nexus operation cancel before start (#2223)

* Test Server: Fix Nexus operation cancel before start

* test

Author: pdoerner

temporal-test-server/src/main/java/io/temporal/internal/testservice/StateMachines.java

@@ -608,13 +608,12 @@ public static StateMachine<NexusOperationData> newNexusOperation(Endpoint endpoi
         .add(NONE, INITIATE, INITIATED, StateMachines::scheduleNexusOperation)
         .add(INITIATED, START, STARTED, StateMachines::startNexusOperation)
         .add(INITIATED, TIME_OUT, TIMED_OUT, StateMachines::timeoutNexusOperation)
-        // Transitions directly to CANCELED if operation has not been started
         // TODO: properly support cancel before start
-        .add(
-            INITIATED,
-            REQUEST_CANCELLATION,
-            CANCELED,
-            StateMachines::reportNexusOperationCancellation)
+        // .add(
+        //     INITIATED,
+        //     REQUEST_CANCELLATION,
+        //     INITIATED,
+        //     StateMachines::requestCancelNexusOperation)
         .add(INITIATED, CANCEL, CANCELED, StateMachines::reportNexusOperationCancellation)
         // Transitions directly from INITIATED to COMPLETE for sync completions
         .add(INITIATED, COMPLETE, COMPLETED, StateMachines::completeNexusOperation)

temporal-test-server/src/main/java/io/temporal/internal/testservice/TestWorkflowMutableStateImpl.java

@@ -41,6 +41,7 @@
 import io.temporal.api.enums.v1.*;
 import io.temporal.api.errordetails.v1.QueryFailedFailure;
 import io.temporal.api.failure.v1.ApplicationFailureInfo;
+import io.temporal.api.failure.v1.CanceledFailureInfo;
 import io.temporal.api.failure.v1.Failure;
 import io.temporal.api.history.v1.*;
 import io.temporal.api.nexus.v1.Endpoint;
@@ -753,14 +754,26 @@ private void processRequestCancelNexusOperation(
           .asRuntimeException();
     }
 
-    operation.action(Action.REQUEST_CANCELLATION, ctx, null, workflowTaskCompletedId);
-    if (isTerminalState(operation.getState())) {
-      // Operation canceled before started, so immediately remove operation since no new
-      // cancellation task will be generated.
+    if (operation.getState() == State.INITIATED) {
       // TODO: properly support cancel before start once server does
+      ctx.addEvent(
+          HistoryEvent.newBuilder()
+              .setEventType(EventType.EVENT_TYPE_NEXUS_OPERATION_CANCEL_REQUESTED)
+              .setNexusOperationCancelRequestedEventAttributes(
+                  NexusOperationCancelRequestedEventAttributes.newBuilder()
+                      .setScheduledEventId(attr.getScheduledEventId())
+                      .setWorkflowTaskCompletedEventId(workflowTaskCompletedId))
+              .build());
+      Failure canceled =
+          Failure.newBuilder()
+              .setMessage("operation canceled before it was started")
+              .setCanceledFailureInfo(CanceledFailureInfo.getDefaultInstance())
+              .build();
+      operation.action(Action.CANCEL, ctx, canceled, workflowTaskCompletedId);
       nexusOperations.remove(scheduleEventId);
       ctx.setNeedWorkflowTask(true);
     } else {
+      operation.action(Action.REQUEST_CANCELLATION, ctx, null, workflowTaskCompletedId);
       ctx.addTimer(
           ProtobufTimeUtils.toJavaDuration(operation.getData().requestTimeout),
           () ->

temporal-test-server/src/test/java/io/temporal/testserver/functional/NexusWorkflowTest.java

@@ -576,7 +576,9 @@ public void testNexusOperationCancelBeforeStart() {
         events.get(0).getNexusOperationCanceledEventAttributes().getFailure();
     assertOperationFailureInfo(failure.getNexusOperationExecutionFailureInfo());
     Assert.assertEquals("nexus operation completed unsuccessfully", failure.getMessage());
-    Assert.assertFalse(failure.hasCause());
+    io.temporal.api.failure.v1.Failure cause = failure.getCause();
+    Assert.assertEquals("operation canceled before it was started", cause.getMessage());
+    Assert.assertNotNull(cause.getCanceledFailureInfo());
   }
 
   @Test(timeout = 15000)