Build issue with humble-future branch of events executor (timer reset support)

[sudhanva-ns]

I’m attempting to use iRobot’s events executor with ROS 2 Humble and am trying to build the humble-future branch of the events executor.

As noted in the README, this branch requires additional support from rclcpp and rcl for resetting timers. I cherry-picked the recommended commits, but I’m running into the following build error when compiling rclcpp:

--- stderr: rclcpp                               
/irobot_ws/src/rclcpp/rclcpp/src/rclcpp/timer.cpp: In member function ‘void rclcpp::TimerBase::set_on_reset_callback(std::function<void(long unsigned int)>)’:
/irobot_ws/src/rclcpp/rclcpp/src/rclcpp/timer.cpp:186:21: error: function template-id ‘cpp_callback_trampoline<rclcpp::TimerBase::set_on_reset_callback(std::function<void(long unsigned int)>)::<lambda(size_t)>, const void*, size_t>’ in nested-name-specifier
  186 |     rclcpp::detail::cpp_callback_trampoline<
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~
  187 |       decltype(new_callback), const void *, size_t>::callback,
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /irobot_ws/src/rclcpp/rclcpp/src/rclcpp/timer.cpp:25:
/irobot_ws/src/rclcpp/rclcpp/include/rclcpp/detail/cpp_callback_trampoline.hpp:58:1: note: ‘template<class UserDataT, class ... Args, class ReturnT> ReturnT rclcpp::detail::cpp_callback_trampoline(UserDataT, Args ...)’ declared here
   58 | cpp_callback_trampoline(UserDataT user_data, Args ... args) noexcept
      | ^~~~~~~~~~~~~~~~~~~~~~~
/irobot_ws/src/rclcpp/rclcpp/src/rclcpp/timer.cpp:194:24: error: no matching function for call to ‘rclcpp::TimerBase::set_on_reset_callback(<unresolved overloaded function type>, const void*)’
  194 |   set_on_reset_callback(
      |   ~~~~~~~~~~~~~~~~~~~~~^
  195 |     rclcpp::detail::cpp_callback_trampoline<
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  196 |       decltype(on_reset_callback_), const void *, size_t>,
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  197 |     static_cast<const void *>(&on_reset_callback_));
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/irobot_ws/src/rclcpp/rclcpp/src/rclcpp/timer.cpp:152:1: note: candidate: ‘void rclcpp::TimerBase::set_on_reset_callback(std::function<void(size_t)>)’
  152 | TimerBase::set_on_reset_callback(std::function<void(size_t)> callback)
      | ^~~~~~~~~
/irobot_ws/src/rclcpp/rclcpp/src/rclcpp/timer.cpp:152:1: note:   candidate expects 1 argument, 2 provided
In file included from /irobot_ws/src/rclcpp/rclcpp/src/rclcpp/timer.cpp:15:
/irobot_ws/src/rclcpp/rclcpp/include/rclcpp/timer.hpp:193:3: note: candidate: ‘void rclcpp::TimerBase::set_on_reset_callback(rcl_event_callback_t, const void*)’
  193 |   set_on_reset_callback(rcl_event_callback_t callback, const void * user_data);
      |   ^~~~~~~~~~~~~~~~~~~~~
/irobot_ws/src/rclcpp/rclcpp/include/rclcpp/timer.hpp:193:46: note:   no known conversion for argument 1 from ‘<unresolved overloaded function type>’ to ‘rcl_event_callback_t’ {aka ‘void (*)(const void*, long unsigned int)’}
  193 |   set_on_reset_callback(rcl_event_callback_t callback, const void * user_data);
      |                         ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
gmake[2]: *** [CMakeFiles/rclcpp.dir/build.make:1119: CMakeFiles/rclcpp.dir/src/rclcpp/timer.cpp.o] Error 1
gmake[2]: *** Waiting for unfinished jobs....
gmake[1]: *** [CMakeFiles/Makefile2:465: CMakeFiles/rclcpp.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2

Environment

OS: Ubuntu 22.04

ROS 2: Humble

Question

Has anyone successfully built the humble-future branch of events executor with timer reset support? Am I missing a required patch or dependency in rclcpp/rcl?

Any guidance or confirmation on the correct set of commits needed would be greatly appreciated.

[mjcarroll]

CC: @alsora or @jmachowinski maybe you have a quick insight here?

[alsora]

The irobot-events-executor repo is not used/maintained since almost 2 years (when irobot moved away from it and started using the events-executor provided in rclcpp).
This is an issue with the instructions provided in that repo, not with rclcpp.

The cherry-picks were functional when done on top of rclcpp humble of 3 years ago (when we froze our internal humble build), but things have likely changed since then, that's why it's broken.

The errors don't ring any bell, i'll look into them this week.

[sudhanva-ns]

Thanks @alsora
I understood that irobot-events-executor is no longer maintained, as it was merged into experimental starting from Iron. Since Humble is still under support, I was wondering if it would be possible to build and maintain it separately to ease future upgrades. At present, our systems are still running on Humble, and a full migration to Jazzy remains a significant challenge. I wouldn’t have raised this request if Humble had already reached end of life, but given its current support status, I thought it was worth asking.