fix(TopicPublisherROS2): prevent crash when enabling Re-Publisher

- GenericPublisher passed its `callbacks_` member by reference to
  rclcpp::PublisherBase. Base init runs before member init, so rclcpp
  read uninitialized std::function memory and crashed inside the
  PublisherBase ctor. Pass a temporary rclcpp::PublisherEventCallbacks{}
  and drop the dead member.

- setEnabled() eagerly created tf2_ros TransformBroadcaster / Static
  broadcaster even for bags without /tf data. On Jazzy/Rolling this
  triggers a separate tf2_ros QoS-override parameter-declaration crash
  inside rclcpp. Defer broadcaster creation to broadcastTF() so it
  only happens once /tf or /tf_static actually carries data.

Closes #477, #759.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: avalen2022

src/TopicPublisherROS2/generic_publisher.h

@@ -30,7 +30,8 @@ class GenericPublisher : public rclcpp::PublisherBase
                    const rosidl_message_type_support_t& type_support)
   // The rclcpp::PublisherBase constructor grew event-callback parameters after Humble (rclcpp 16.x).
 #if RCLCPP_VERSION_GTE(17, 0, 0)
-    : rclcpp::PublisherBase(node_base, topic_name, type_support, rcl_publisher_get_default_options(), callbacks_, true)
+    : rclcpp::PublisherBase(node_base, topic_name, type_support, rcl_publisher_get_default_options(),
+                            rclcpp::PublisherEventCallbacks{}, true)
 #else
     : rclcpp::PublisherBase(node_base, topic_name, type_support, rcl_publisher_get_default_options())
 #endif
@@ -58,9 +59,6 @@ class GenericPublisher : public rclcpp::PublisherBase
     return std::make_shared<GenericPublisher>(node.get_node_base_interface().get(), topic_name, *type_support);
   }
 
-#if RCLCPP_VERSION_GTE(17, 0, 0)
-  rclcpp::PublisherEventCallbacks callbacks_;
-#endif
 };
 
 #endif  // GENERIC_PUBLISHER_H

src/TopicPublisherROS2/publisher_ros2.cpp

@@ -111,15 +111,6 @@ void TopicPublisherROS2::setEnabled(bool to_enable)
 
     updatePublishers();
 
-    if (!_tf_broadcaster)
-    {
-      _tf_broadcaster = std::make_unique<tf2_ros::TransformBroadcaster>(*_node);
-    }
-    if (!_tf_static_broadcaster)
-    {
-      _tf_static_broadcaster = std::make_unique<tf2_ros::StaticTransformBroadcaster>(*_node);
-    }
-
     _previous_play_index = std::numeric_limits<int>::max();
   }
   else
@@ -293,10 +284,18 @@ void TopicPublisherROS2::broadcastTF(double current_time)
     }
     if (transforms_ptr == &transforms)
     {
+      if (!_tf_broadcaster)
+      {
+        _tf_broadcaster = std::make_shared<tf2_ros::TransformBroadcaster>(*_node);
+      }
       _tf_broadcaster->sendTransform(transforms_vector);
     }
     else
     {
+      if (!_tf_static_broadcaster)
+      {
+        _tf_static_broadcaster = std::make_shared<tf2_ros::StaticTransformBroadcaster>(*_node);
+      }
       _tf_static_broadcaster->sendTransform(transforms_vector);
     }
   }