[Butakus]

Hi, it seems the Qt5/Qt6 issue is never resolved...

On Ubuntu 24.04, navmap_rviz_plugin fails to configure when the Qt6 development files are installed:

CMake Error at /opt/ros/rolling/share/rviz_common/cmake/ament_cmake_export_dependencies-extras.cmake:21 (find_package):
  Found package configuration file:
    /usr/lib/x86_64-linux-gnu/cmake/Qt5/Qt5Config.cmake
  but it set Qt5_FOUND to FALSE so package "Qt5" is considered to be NOT FOUND.
  Reason given by package:
  The Qt5 package requires at least one component

rviz_common 15.2.2 is built against Qt5, but its rviz_common-extras.cmake looks for Qt6 first and only falls back to Qt5 if Qt6 is missing. With Qt6 installed, Qt5 is never loaded, and the exported-dependencies step then runs a bare find_package(Qt5), which fails.

The existing Qt detection that we have in the CMakeLists.txt for the plugin (get_target_property on rviz_common::rviz_common) runs after find_package(rviz_common), so CMake never reaches it. CMake aborts with an error when calling find_package(rviz_common).

Fix

Before find_package(rviz_common), read rviz_common's exported dependencies to work out whether it uses Qt5 or Qt6:

• set qt_major, which is used for find_package(Qt${qt_major} ...) and linking, as before;
• when rviz uses Qt5, set CMAKE_DISABLE_FIND_PACKAGE_Qt6 so rviz's extras don't pick up Qt6.