Nexus Standalone: translate already started err

Author: stephanos

chasm/lib/nexusoperation/handler.go

@@ -51,6 +51,13 @@ func (h *handler) StartNexusOperation(
 		),
 	)
 	if err != nil {
+		if alreadyStartedErr, ok := errors.AsType[*chasm.ExecutionAlreadyStartedError](err); ok {
+			return nil, serviceerror.NewAlreadyExistsf(
+				"nexus operation execution already started: request_id=%s, run_id=%s",
+				alreadyStartedErr.CurrentRequestID,
+				alreadyStartedErr.CurrentRunID,
+			)
+		}
 		return nil, err
 	}
 

tests/nexus_standalone_test.go

@@ -148,6 +148,9 @@ func TestStartStandaloneNexusOperation(t *testing.T) {
 			RequestId:   "different-request-id",
 		})
 		s.Error(err)
+		var alreadyStartedErr *serviceerror.AlreadyExists
+		s.ErrorAs(err, &alreadyStartedErr)
+		s.ErrorContains(err, "nexus operation execution already started")
 
 		// Second start with same request ID should return existing run.
 		resp2, err := startNexusOperation(s, &workflowservice.StartNexusOperationExecutionRequest{