Fix SIRI update travel back in time

src/ext-test/java/org/opentripplanner/ext/siri/SiriTimetableSnapshotSourceTest.java

@@ -63,6 +63,31 @@ void testAddJourney() {
     );
   }
 
+  @Test
+  void testAddedJourneyWithInvalidScheduledData() {
+    var env = RealtimeTestEnvironment.siri();
+
+    // Create an extra journey with invalid planned data (travel back in time)
+    // and valid real time data
+    var createExtraJourney = new SiriEtBuilder(env.getDateTimeHelper())
+      .withEstimatedVehicleJourneyCode("newJourney")
+      .withIsExtraJourney(true)
+      .withOperatorRef(env.operator1Id.getId())
+      .withLineRef(env.route1Id.getId())
+      .withEstimatedCalls(builder ->
+        builder
+          .call(env.stopA1)
+          .departAimedExpected("10:58", "10:48")
+          .call(env.stopB1)
+          .arriveAimedExpected("10:08", "10:58")
+      )
+      .buildEstimatedTimetableDeliveries();
+
+    var result = env.applyEstimatedTimetable(createExtraJourney);
+    assertEquals(0, result.successful());
+    assertFailure(UpdateError.UpdateErrorType.NEGATIVE_HOP_TIME, result);
+  }
+
   @Test
   void testReplaceJourney() {
     var env = RealtimeTestEnvironment.siri();

src/ext/java/org/opentripplanner/ext/siri/AddedTripBuilder.java

@@ -216,6 +216,11 @@ Result<TripUpdate, UpdateError> build() {
       aimedStopTimes,
       transitModel.getDeduplicator()
     );
+    // validate the scheduled trip times
+    // they are in general superseded by real-time trip times
+    // but in case of trip cancellation, OTP will fall back to scheduled trip times
+    // therefore they must be valid
+    tripTimes.validateNonIncreasingTimes();
     tripTimes.setServiceCode(transitModel.getServiceCodes().get(trip.getServiceId()));
     pattern.add(tripTimes);
     RealTimeTripTimes updatedTripTimes = tripTimes.copyScheduledTimes();

src/main/java/org/opentripplanner/transit/model/timetable/RealTimeTripTimes.java

@@ -261,9 +261,15 @@ public void setRealTimeState(final RealTimeState realTimeState) {
    *
    * @throws org.opentripplanner.transit.model.framework.DataValidationException of the first error
    * found.
+   *
+   * Note! This is a duplicate (almost) of the same method in ScheduledTripTimes.
+   * We should aim for just one implementation. We need to decide how to do this.
+   * A common abstract base class would simplify it, but may lead to other problems and performance
+   * overhead. We should look back on this after refactoring
+   * the rest of the timetable classes (calendar/patterns).
    */
   public void validateNonIncreasingTimes() {
-    final int nStops = arrivalTimes.length;
+    final int nStops = scheduledTripTimes.getNumStops();
     int prevDep = -9_999_999;
     for (int s = 0; s < nStops; s++) {
       final int arr = getArrivalTime(s);