Fixes for compiling with clang on macOS (arm64)

[srmainwaring]

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Basic Info

Info	Please fill out this column
Ticket(s) this addresses	#3828
Primary OS tested on	MacOS (arm64 and intel)
Robotic platform tested on	Gazebo / ArduPilot simulation of Iris copter

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Description of contribution in a few bullet points

• Changes fix compiler errors when building on macOS 13.4 with clang (version details below).
• Broken out into changes per submodule / type of error to aid dropping changes that may not be desired (e.g. replacement of std::experimental::filesystem with std::filesystem).
• Primary development and testing against ROS 2 Humble and the nav2 humble branch.
• This PR rebased onto main and built against ROS Rolling (the port of ROS Rolling to macOS is ongoing, so cannot fully test all nav2 libraries on macOS until that is complete).

% clang --version
Apple clang version 14.0.3 (clang-1403.0.22.14.1)
Target: arm64-apple-darwin22.5.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

Description of documentation updates required from your changes

• No functional changes.

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Future work that may be required in bullet points

• There are additional changes required to support macOS - these require more work to make them compatible with other platforms so have not been included at this stage.

For Maintainers:

• Check that any new parameters added are updated in navigation.ros.org
• Check that any significant change is added to the migration guide
• Check that any new features OR changes to existing behaviors are reflected in the tuning guide
• Check that any new functions have Doxygen added
• Check that any new features have test coverage
• Check that any new plugins is added to the plugins page
• If BT Node, Additionally: add to BT's XML index of nodes for groot, BT package's readme table, and BT library lists

[mergify]

@srmainwaring, your PR has failed to build. Please check CI outputs and resolve issues.
You may need to rebase or pull in main due to API changes (or your contribution genuinely fails).

[SteveMacenski]

The build failure looks like an API difference in Humble vs rolling. Its a trivial change, but one that would need to be made to compile

[srmainwaring]

The build failure looks like an API difference in Humble vs rolling.

I'm working through these now and will force push the changes once I've got a clean build. A couple of libraries in Rolling on macOS are proving tricky. Will shift back from draft once it's clear.

[srmainwaring]

What is the preferred treatment for unused parameters?

 float NodeLattice::getHeuristicCost(
   const Coordinates & node_coords,
   const Coordinates & goal_coords,
   [[maybe_unused]] const nav2_costmap_2d::Costmap2D * costmap)
 {

or

 float NodeLattice::getHeuristicCost(
   const Coordinates & node_coords,
   const Coordinates & goal_coords,
   const nav2_costmap_2d::Costmap2D * /*costmap*/)
 {

[SteveMacenski]

Second one. The C++98 in me will die kicking and screaming

[srmainwaring]

There's one error in the tests - it looks like a code style conflict from a test I edited, but still trying to interpret the CI message.

[SteveMacenski]

I see 8 failing messages and if you click on each in the "Tests" tab, it shows you exactly the failure and where it is (and in some cases, what to do to fix it explicitly)

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (1efc96c) 64.15% compared to head (8ac6406) 90.37%.
Report is 3 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3831       +/-   ##
===========================================
+ Coverage   64.15%   90.37%   +26.21%     
===========================================
  Files         413      413               
  Lines       18241    18239        -2     
===========================================
+ Hits        11703    16483     +4780     
+ Misses       6538     1756     -4782     

Files	Coverage Δ
nav2_amcl/src/pf/pf.c	91.66% <ø> (+91.66%)	⬆️
nav2_amcl/src/pf/pf_vector.c	100.00% <100.00%> (+100.00%)	⬆️
...tree/include/nav2_behavior_tree/bt_action_node.hpp	84.87% <100.00%> (+15.12%)	⬆️
...clude/nav2_behavior_tree/bt_cancel_action_node.hpp	80.00% <100.00%> (ø)
...vior_tree/plugins/condition/is_stuck_condition.cpp	98.11% <100.00%> (+3.77%)	⬆️
...nclude/nav2_behaviors/plugins/drive_on_heading.hpp	92.64% <100.00%> (+92.64%)	⬆️
.../nav2_bt_navigator/navigators/navigate_to_pose.hpp	100.00% <100.00%> (+100.00%)	⬆️
nav2_controller/src/controller_server.cpp	89.19% <100.00%> (+76.45%)	⬆️
...clude/nav2_costmap_2d/denoise/image_processing.hpp	98.06% <100.00%> (+<0.01%)	⬆️
nav2_costmap_2d/src/clear_costmap_service.cpp	42.00% <ø> (+12.00%)	⬆️
... and 6 more

... and 185 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[SteveMacenski]

Overall LGTM!

[srmainwaring]

This is definitely a vector https://navigation.ros.org/configuration/packages/collision_monitor/configuring-collision-monitor-node.html

Yes, and on inspection from the line below my change I can see the data is a vector as well. This was the clang error:

[ 97%] Building CXX object test/CMakeFiles/collision_monitor_node_test.dir/collision_monitor_node_test.cpp.o
/Users/rhys/Code/ros2/rolling/ros2-nav/src/navigation2/nav2_collision_monitor/test/collision_monitor_node_test.cpp:1026:61: error: braces around scalar initializer [-Werror,-Wbraced-scalar-init]
  cm_->declare_parameter("polygons", rclcpp::ParameterValue({"Stop",}));
                                                            ^~~~~~~~~
1 error generated.

Not sure why it's not resolving the list to a std::vector<std::string> and calling the matching explicit constructor for rclcpp::ParameterValue. The correction in 8ac6406 forces the desired ctor.

[srmainwaring]

btw - to build on macOS (and fully close #3828) there is a change needed to the nav2_mppi_controller CMakeLists.txt to disable some of the compiler settings (AVX2, FMA, etc). I haven't included those here and will post in a follow up PR.