no match for 'operator==' error

[k-ish0212]

I've encountered such an error when compiling ros2 humble. It looks rcputils::fs::path operator error but the operator seems compiled through colcon build.

Starting >>> rcpputils
Starting >>> rosidl_runtime_c
--- stderr: orocos_kdl_vendor
Cloning into 'orocos_kdl-507de66'...
HEAD is now at 507de66 Fix CMake warning on Windows (#392)
Submodule 'python_orocos_kdl/pybind11' (https://github.com/pybind/pybind11.git) registered for path 'python_orocos_kdl/pybind11'
Cloning into '/root/xarm/ros2_humble/build/orocos_kdl_vendor/orocos_kdl-507de66-prefix/src/orocos_kdl-507de66/python_orocos_kdl/pybind11'...

---

Finished <<< orocos_kdl_vendor [56.3s]
Starting >>> python_orocos_kdl_vendor
Finished <<< python_orocos_kdl_vendor [2.23s]
Finished <<< rosidl_runtime_c [15.1s]
Starting >>> rosidl_runtime_cpp
Starting >>> rosidl_generator_c
Starting >>> rmw
Starting >>> rosidl_typesupport_introspection_c
Finished <<< rcpputils [16.9s]
Starting >>> rcl_logging_interface
Starting >>> libyaml_vendor
Starting >>> class_loader
Finished <<< rosidl_typesupport_introspection_c [6.88s]
Finished <<< rosidl_generator_c [10.9s]
Finished <<< rcl_logging_interface [10.3s]
Starting >>> rcl_logging_noop
Starting >>> rcl_logging_spdlog
Finished <<< rcl_logging_noop [1.88s]
--- stderr: libyaml_vendor
Cloning into 'libyaml-0.2.5'...
HEAD is now at 2c891fc Changes for v0.2.5 release

---

Finished <<< libyaml_vendor [13.0s]
Finished <<< rosidl_runtime_cpp [15.0s]
Starting >>> rosidl_generator_cpp
Starting >>> rosidl_typesupport_introspection_cpp
Finished <<< class_loader [18.5s]

Starting >>> pluginlib
Finished <<< rosidl_typesupport_introspection_cpp [6.20s]
Finished <<< rcl_logging_spdlog [10.2s]
Finished <<< rmw [27.9s]
Starting >>> rcl_yaml_param_parser
--- stderr: pluginlib
In file included from /root/xarm/ros2_humble/src/ros/pluginlib/pluginlib/include/pluginlib/class_loader.hpp:334,
from /root/xarm/ros2_humble/src/ros/pluginlib/pluginlib/test/utest.cpp:33:
/root/xarm/ros2_humble/src/ros/pluginlib/pluginlib/include/pluginlib/./class_loader_imp.hpp: In member function ‘std::string pluginlib::ClassLoader::getPackageFromPluginXMLFilePath(const string&)’:
/root/xarm/ros2_humble/src/ros/pluginlib/pluginlib/include/pluginlib/./class_loader_imp.hpp:589:39: error: no match for ‘operator==’ (operand types are ‘rcpputils::fs::path’ and ‘rcpputils::fs::path’)
589 | if (parent.string().empty() || (p == parent)) {
| ~ ^~ ~~~~~~
| | |
| | rcpputils::fs::path
| rcpputils::fs::path
make[2]: *** [CMakeFiles/pluginlib_utest.dir/build.make:63: CMakeFiles/pluginlib_utest.dir/test/utest.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:187: CMakeFiles/pluginlib_utest.dir/all] Error 2
make: *** [Makefile:141: all] Error 2

---

Failed <<< pluginlib [7.80s, exited with code 2]
Aborted <<< rcl_yaml_param_parser [2.20s]
Aborted <<< rosidl_generator_cpp [24.5s]
Aborted <<< fastrtps [2min 41s]
Aborted <<< rviz_ogre_vendor [4min 14s]

Summary: 139 packages finished [4min 39s]
1 package failed: pluginlib

Does anyone know how to solve it?
Thank you.

[jdlangs]

Based on your file paths, I'm guessing you're trying to build Humble in a 20.04 container which I am doing too and I saw the exact same error. It was because I forgot to remove the Foxy versions of packages on the AMENT_PREFIX_PATH. So I believe pluginlib was compiling against the wrong version of rcpputils.