temporary fix bug null pointer (#5749)

* temporary fix bug null pointer

Signed-off-by: suifengersan123 <yangabc810@gmail.com>

* add return

Signed-off-by: suifengersan123 <yangabc810@gmail.com>

* remove return

Signed-off-by: suifengersan123 <yangabc810@gmail.com>

---------

Signed-off-by: suifengersan123 <yangabc810@gmail.com>

Author: suifengersan123

nav2_costmap_2d/src/costmap_layer.cpp

@@ -57,6 +57,12 @@ void CostmapLayer::matchSize()
 {
   std::lock_guard<Costmap2D::mutex_t> guard(*getMutex());
   Costmap2D * master = layered_costmap_->getCostmap();
+  if (!master) {
+    RCLCPP_WARN(
+      rclcpp::get_logger("nav2_costmap_2d"),
+      "Cannot match size for layer, master costmap is not initialized yet.");
+    return;
+  }
   resizeMap(
     master->getSizeInCellsX(), master->getSizeInCellsY(), master->getResolution(),
     master->getOriginX(), master->getOriginY());

nav2_costmap_2d/src/layered_costmap.cpp

@@ -117,7 +117,9 @@ void LayeredCostmap::resizeMap(
   for (vector<std::shared_ptr<Layer>>::iterator plugin = plugins_.begin();
     plugin != plugins_.end(); ++plugin)
   {
-    (*plugin)->matchSize();
+    if (*plugin) {
+      (*plugin)->matchSize();
+    }
   }
   for (vector<std::shared_ptr<Layer>>::iterator filter = filters_.begin();
     filter != filters_.end(); ++filter)