Check validity of executor pointer

Author: Mauro Passerino

rclcpp/include/rclcpp/executors/events_executor.hpp

@@ -187,6 +187,11 @@ class EventsExecutor : public rclcpp::Executor
   static void
   push_event(const void * executor_ptr, rmw_listener_event_t event)
   {
+    // Check if the executor pointer is not valid
+    if (!executor_ptr) {
+      throw std::runtime_error("The executor pointer is not valid.");
+    }
+
     // Cast executor_ptr to this (need to remove constness)
     auto this_executor = const_cast<executors::EventsExecutor *>(
       static_cast<const executors::EventsExecutor *>(executor_ptr));