Removing a Workflow.GetVersion call can cause NDE if there are multiple parallel workflow threads running.

[Quinn-With-Two-Ns]

Expected Behavior

Removing a Workflow.GetVersion call should never cause a NDE

Actual Behavior

Removing a Workflow.GetVersion call can cause a NDE if there are multiple workflow threads running.

Steps to Reproduce the Problem

public class GetVersionMultithreadingRemoveTest {

  private static boolean hasReplayed;

  @Rule
  public SDKTestWorkflowRule testWorkflowRule =
      SDKTestWorkflowRule.newBuilder()
          .setWorkflowTypes(TestGetVersionWorkflowImpl.class)
          .setActivityImplementations(new TestActivitiesImpl())
          // Forcing a replay. Full history arrived from a normal queue causing a replay.
          .setWorkerOptions(
              WorkerOptions.newBuilder()
                  .setStickyQueueScheduleToStartTimeout(Duration.ZERO)
                  .build())
          .build();

  @Test
  public void testGetVersionMultithreadingRemoval() {
    TestWorkflow1 workflowStub =
        testWorkflowRule.newWorkflowStubTimeoutOptions(TestWorkflow1.class);
    String result = workflowStub.execute(testWorkflowRule.getTaskQueue());
    assertTrue(hasReplayed);
    assertEquals("activity1", result);
  }

  public static class TestGetVersionWorkflowImpl implements TestWorkflow1 {

    @Override
    public String execute(String taskQueue) {
      VariousTestActivities testActivities =
          Workflow.newActivityStub(
              VariousTestActivities.class,
              SDKTestOptions.newActivityOptionsForTaskQueue(taskQueue));

      Async.procedure(
          () -> {
            Workflow.sleep(1000);
          });

      // Test removing a version check in replaying code with an additional thread running.
      if (!WorkflowUnsafe.isReplaying()) {
        int version = Workflow.getVersion("changeId", 1, 2);
        assertEquals(version, 2);
      } else {
        hasReplayed = true;
      }
      String result =
          "activity" + testActivities.activity1(1); // This is executed in non-replay mode.
      return result;
    }
  }
}

This happens because Workflow.getVersion causes the current thread to block so when it is removed the order of execution can change.

Specifications

• Version: All

The current workaround is to not remove the Workflow.getVersion call