Why is catkin_make_isolated trying to build so much ?
Basically I don't understand the ROS build system.
I installed ROS from source on a Raspberry Pi 4 under Raspbian Buster Stretch using this method. I also managed to get raspicam_node to compile and install. I used Raspbian because it provides support for the Pi's GPU.
Everything works, but whenever I try to build my own package with catkin_make_isolated, ROS appears to try to rebuild the entire system - it takes hours ! Also I don't know if I should be using catkin_make(like I always used to), or catkin_make_isolated. I don't know why ROS wants to rebuild the whole system - I installed the system to /opt/ROS/melodic, and thought that it should now just recompile my own package. Something has got very messed up.
My directory structure is now:
catkin_ws
- build
- build_isolated
- devel
- devel_isolated
- install
- src
I don't think I should have build and build_isolated etc. Some packages exist in both, and some are just in one. I don't know why I have both.
Any clarification would be welcome.