From a33e2462e92e6dd0e6c0dc0cc3385dc342b12f31 Mon Sep 17 00:00:00 2001
From: Ian Chen <ichen@openrobotics.org>
Date: Mon, 26 Aug 2024 16:42:47 -0700
Subject: [PATCH] Check ranges before access (#2540)

Added a check for non-empty laser scan ranges before accessing the elements.

Signed-off-by: Ian Chen <ichen@openrobotics.org>
---
 src/systems/elevator/Elevator.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/systems/elevator/Elevator.cc b/src/systems/elevator/Elevator.cc
index 53c172dcef..12fd5287f4 100644
--- a/src/systems/elevator/Elevator.cc
+++ b/src/systems/elevator/Elevator.cc
@@ -421,6 +421,9 @@ void ElevatorPrivate::UpdateState(const gz::sim::UpdateInfo &_info,
 void ElevatorPrivate::OnLidarMsg(size_t _floorLevel,
                                  const msgs::LaserScan &_msg)
 {
+  if (_msg.ranges_size() <= 0)
+    return;
+
   bool isDoorwayBlocked = _msg.ranges(0) < _msg.range_max() - 0.005;
   if (isDoorwayBlocked == this->isDoorwayBlockedStates[_floorLevel]) return;
   std::lock_guard<std::recursive_mutex> lock(this->mutex);