Avoid NPE in dealWithException of QueryExecution

Author: JackieTien97

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/execution/QueryExecution.java

@@ -462,23 +462,25 @@ private <T> Optional<T> getResult(ISourceHandleSupplier<T> dataSupplier) throws
   private void dealWithException(Throwable t) throws IoTDBException {
     t = getRootCause(t);
     stateMachine.transitionToFailed(t);
-    if (stateMachine.getFailureStatus() != null) {
-      throw new IoTDBException(
-          stateMachine.getFailureStatus().getMessage(), stateMachine.getFailureStatus().code);
-    } else if (stateMachine.getFailureException() != null) {
+    TSStatus status = stateMachine.getFailureStatus();
+    if (status != null) {
+      throw new IoTDBException(status.getMessage(), status.code);
+    } else {
       Throwable rootCause = stateMachine.getFailureException();
-      if (rootCause instanceof IoTDBRuntimeException) {
-        throw (IoTDBRuntimeException) rootCause;
-      } else if (rootCause instanceof IoTDBException) {
-        throw (IoTDBException) rootCause;
-      } else if (rootCause instanceof DateTimeParseException) {
-        throw new IoTDBRuntimeException(
-            rootCause.getMessage(), DATE_OUT_OF_RANGE.getStatusCode(), true);
+      if (rootCause != null) {
+        if (rootCause instanceof IoTDBRuntimeException) {
+          throw (IoTDBRuntimeException) rootCause;
+        } else if (rootCause instanceof IoTDBException) {
+          throw (IoTDBException) rootCause;
+        } else if (rootCause instanceof DateTimeParseException) {
+          throw new IoTDBRuntimeException(
+              rootCause.getMessage(), DATE_OUT_OF_RANGE.getStatusCode(), true);
+        }
+        throw new IoTDBException(rootCause, TSStatusCode.EXECUTE_STATEMENT_ERROR.getStatusCode());
+      } else {
+        throwIfUnchecked(t);
+        throw new IoTDBException(t, TSStatusCode.QUERY_PROCESS_ERROR.getStatusCode());
       }
-      throw new IoTDBException(rootCause, TSStatusCode.EXECUTE_STATEMENT_ERROR.getStatusCode());
-    } else {
-      throwIfUnchecked(t);
-      throw new IoTDBException(t, TSStatusCode.QUERY_PROCESS_ERROR.getStatusCode());
     }
   }