Make it work by checking the type of the stamp field.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

CMakeLists.txt

@@ -29,6 +29,7 @@ endif()
 # find dependencies
 find_package(ament_cmake REQUIRED)
 find_package(ament_cmake_ros REQUIRED)
+find_package(builtin_interfaces REQUIRED)
 find_package(rcl REQUIRED)
 find_package(rcpputils REQUIRED)
 find_package(rosidl_default_generators REQUIRED)
@@ -47,6 +48,7 @@ target_include_directories(${PROJECT_NAME} PUBLIC
   "$<INSTALL_INTERFACE:include/${PROJECT_NAME}>")
 
 ament_target_dependencies(${PROJECT_NAME}
+  "builtin_interfaces"
   "rcl"
   "rcpputils"
   "statistics_msgs"
@@ -66,7 +68,7 @@ ament_export_libraries(${PROJECT_NAME})
 # Export modern CMake targets
 ament_export_targets(${PROJECT_NAME})
 
-ament_export_dependencies("rcl" "rcpputils" "rosidl_default_runtime" "statistics_msgs")
+ament_export_dependencies("builtin_interfaces" "rcl" "rcpputils" "rosidl_default_runtime" "statistics_msgs")
 
 if(BUILD_TESTING)
   find_package(ament_lint_auto REQUIRED)

include/libstatistics_collector/topic_statistics_collector/received_message_age.hpp

@@ -25,6 +25,7 @@
 
 #include "libstatistics_collector/topic_statistics_collector/topic_statistics_collector.hpp"
 
+#include "builtin_interfaces/msg/time.hpp"
 #include "rcl/time.h"
 #include "rcutils/logging_macros.h"
 
@@ -34,18 +35,20 @@ namespace topic_statistics_collector
 {
 
 /**
- * True if the message has a header with a subfield stamp
+ * False if the message does not have a header
  * @tparam M
  */
-template<typename M, typename D = decltype(M().header.stamp)>
-struct HasHeader : public std::true_type {};
+template<typename M, typename = void>
+struct HasHeader : public std::false_type {};
 
 /**
- * False if the message does not have a header
+ * True if the message has a field named 'header' with a subfield named 'stamp' of
+ * type builtin_interfaces::msg::Time
  * @tparam M
  */
 template<typename M>
-struct HasHeader<M, void>: public std::false_type {};
+struct HasHeader<M, typename std::enable_if<std::is_same<builtin_interfaces::msg::Time,
+  decltype(M().header.stamp)>::value>::type>: public std::true_type {};
 
 /**
  * Return a boolean flag indicating the timestamp is not set

package.xml

@@ -12,6 +12,7 @@
 
   <build_depend>rosidl_default_generators</build_depend>
 
+  <depend>builtin_interfaces</depend>
   <depend>rcl</depend>
   <depend>rcpputils</depend>
   <depend>statistics_msgs</depend>