SMAC smooth_path dynamic parameter causes crash

[tonynajjar]

Bug report

Required Info:

• ROS2 Version:
  • jazzy
• Version or commit hash:
  • main

Steps to reproduce issue

using SmacPlannerLattice change smooth_path parameter dynamically (i tried from false to true). Probably reproduces for SmacPlannerHybrid as well.

Expected behavior

No crash

Actual behavior

Crash:

[planner_server-3] terminate called after throwing an instance of 'rclcpp::exceptions::ParameterModifiedInCallbackException'
[planner_server-3]   what():  cannot set or declare a parameter, or change the callback from within set callback
[planner_server-3] Stack trace (most recent call last):
[planner_server-3] #26   Object "/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2", at 0xffffffffffffffff, in 
[planner_server-3] #25   Object "/home/angsa/underlay_ws/build/nav2_planner/planner_server", at 0x65116d546a14, in _start
[planner_server-3] #24   Object "/usr/lib/x86_64-linux-gnu/libc.so.6", at 0x77876b73e28a, in __libc_start_main
[planner_server-3] #23   Object "/usr/lib/x86_64-linux-gnu/libc.so.6", at 0x77876b73e1c9, in 
[planner_server-3] #22   Object "/home/angsa/underlay_ws/build/nav2_planner/planner_server", at 0x65116d5468bd, in main
[planner_server-3] #21   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bd26258, in rclcpp::spin(std::shared_ptr<rclcpp::node_interfaces::NodeBaseInterface>)
[planner_server-3] #20   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bd2df33, in rclcpp::executors::SingleThreadedExecutor::spin()
[planner_server-3] #19   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bd1c079, in rclcpp::Executor::execute_any_executable(rclcpp::AnyExecutable&)
[planner_server-3] #18   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bd17db3, in rclcpp::Executor::execute_service(std::shared_ptr<rclcpp::ServiceBase>)
[planner_server-3] #17   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bdf1f09, in 
[planner_server-3] #16   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bdaf774, in 
[planner_server-3] #15   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bda1cb7, in 
[planner_server-3] #14   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bdf26d8, in 
[planner_server-3] #13   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bd613fe, in rclcpp::node_interfaces::NodeParameters::set_parameters_atomically(std::vector<rclcpp::Parameter, std::allocator<rclcpp::Parameter> > const&)
[planner_server-3] #12   Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bd5efb3, in 
[planner_server-3] #11   Object "/home/angsa/underlay_ws/install/nav2_smac_planner/lib/libnav2_smac_planner_lattice.so", at 0x7787399b0461, in std::_Function_handler<rcl_interfaces::msg::SetParametersResult_<std::allocator<void> > (std::vector<rclcpp::Parameter, std::allocator<rclcpp::Parameter> > const&), std::_Bind<rcl_interfaces::msg::SetParametersResult_<std::allocator<void> > (nav2_smac_planner::SmacPlannerLattice::*(nav2_smac_planner::SmacPlannerLattice*, std::_Placeholder<1>))(std::vector<rclcpp::Parameter, std::allocator<rclcpp::Parameter> >)> >::_M_invoke(std::_Any_data const&, std::vector<rclcpp::Parameter, std::allocator<rclcpp::Parameter> > const&)
[planner_server-3] #10   Object "/home/angsa/underlay_ws/install/nav2_smac_planner/lib/libnav2_smac_planner_lattice.so", at 0x778739970a41, in nav2_smac_planner::SmacPlannerLattice::dynamicParametersCallback(std::vector<rclcpp::Parameter, std::allocator<rclcpp::Parameter> >)
[planner_server-3] #9    Object "/home/angsa/underlay_ws/install/nav2_smac_planner/lib/libnav2_smac_planner_lattice.so", at 0x778739994165, in nav2_smac_planner::SmootherParams::get(std::shared_ptr<nav2::LifecycleNode>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)
[planner_server-3] #8    Object "/home/angsa/underlay_ws/install/nav2_smac_planner/lib/libnav2_smac_planner_lattice.so", at 0x778739990374, in void nav2::declare_parameter_if_not_declared<std::shared_ptr<nav2::LifecycleNode> >(std::shared_ptr<nav2::LifecycleNode>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, rclcpp::ParameterValue const&, rcl_interfaces::msg::ParameterDescriptor_<std::allocator<void> > const&)
[planner_server-3] #7    Object "/opt/ros/jazzy/lib/librclcpp.so", at 0x77876bce5295, in 
[planner_server-3] #6    Object "/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.33", at 0x77876ba11390, in __cxa_throw
[planner_server-3] #5    Object "/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.33", at 0x77876b9fba54, in std::terminate()
[planner_server-3] #4    Object "/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.33", at 0x77876ba110d9, in 
[planner_server-3] #3    Object "/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.33", at 0x77876b9fbff4, in 
[planner_server-3] #2    Object "/usr/lib/x86_64-linux-gnu/libc.so.6", at 0x77876b73c8fe, in abort
[planner_server-3] #1    Object "/usr/lib/x86_64-linux-gnu/libc.so.6", at 0x77876b75927d, in raise
[planner_server-3] #0    Object "/usr/lib/x86_64-linux-gnu/libc.so.6", at 0x77876b7b2b2c, in pthread_kill
[planner_server-3] Aborted (Signal sent by tkill() 1033830 1000)
[ERROR] [planner_server-3]: process has died [pid 1033830, exit code -6, cmd '/home/angsa/underlay_ws/install/nav2_planner/lib/nav2_planner/planner_server --ros-args -r __node:=planner_server --params-file /home/angsa/overlay_ws/src/angsa-robot/angsa_bringup/config/base/nav2.yaml --params-file /home/angsa/overlay_ws/install/angsa_navigation_playground/share/angsa_navigation_playground/config/nav2_overrides.yaml -r /map:=/playground_map'].

Reproduction instructions

Additional information

From the error message [planner_server-3] what(): cannot set or declare a parameter, or change the callback from within set callback, I'm pretty sure it's because params.get(node, _name); calls
declare_parameter_if_not_declared

[SteveMacenski]

This rhymes with another issue we fixed a few weeks ago. I assume your config has smooth_path: false in your config file, yes? If you set it to true, can you reproduce? If not, then the solution is to do the following outside of the if condition so it always runs to declare the parameters. That way if later toggled on/off the parameters are not being declared. This is a bug IMO in ros2 dynamic parameter callback design, but I understand the thinking.

    SmootherParams params;
    params.get(node, name);

Let me know if that works. I can open PR(s) if you don't have time to

[tonynajjar]

I assume your config has smooth_path: false in your config file, yes?

yes

It's not really an issue for me so I wouldn't invest more time on it (sorry gotta prioritize). I just wanted to flag that it's something I saw

[SteveMacenski]

This is easy to solve

@claude in the Smac Planner Hybrid A* and Smac Planner State Lattice, change in the configure method

  if (smooth_path) {
    SmootherParams params;
    params.get(node, name);
    _smoother = std::make_unique<Smoother>(params);
    _smoother->initialize(_metadata.min_turning_radius);
  }

to read

  SmootherParams params;
  params.get(node, name);
  if (smooth_path) {
    _smoother = std::make_unique<Smoother>(params);
    _smoother->initialize(_metadata.min_turning_radius);
  }

[claude]

Claude finished @SteveMacenski's task —— View job • claude/issue-5472-20250821_184253 • Create PR ➔

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Fixing SMAC Planner Parameter Declaration Issue

I'll fix the crash when dynamically changing the smooth_path parameter by moving the SmootherParams declaration outside the conditional block in both SMAC planners.

Todo List:

• Find SMAC Planner files (Hybrid A* and State Lattice)
• Read current configure method implementations
• Move SmootherParams declaration outside if condition in Hybrid A*
• Move SmootherParams declaration outside if condition in State Lattice
• Run build/lint checks if available
• Commit changes and provide PR link

Changes Made:

Both files now declare SmootherParams outside the if (smooth_path) condition, ensuring parameters are always available for dynamic reconfiguration:

smac_planner_hybrid.cpp:276-281 and smac_planner_lattice.cpp:233-238 now use:

// Initialize path smoother
SmootherParams params;
params.get(node, name);
if (smooth_path) {
  _smoother = std::make_unique<Smoother>(params);
  _smoother->initialize(...);
}

This prevents the ParameterModifiedInCallbackException when dynamically toggling smooth_path from false to true.

Completed: Changes committed to branch claude/issue-5472-20250821_184253 (commit aeaa8e0).

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