buildRosPackage: reasons for building ament_python as we do

distros/build-ros-package/default.nix

@@ -31,10 +31,12 @@ else stdenv.mkDerivation) (args // {
 } // lib.optionalAttrs (buildType == "ament_python") {
   dontUseCmakeConfigure = true;
 
-  # Modelled after colcon.
+  # Modeled after colcon.
   # As of 0.12.1, colcon uses the legacy distutils install.py script, so we do
   # the same. Using modern techniques, such as "pip install" with setuptools,
-  # causes issues due to differences in setup.cfg interpretation.
+  # causes issues due to differences in setup.cfg interpretation. In particular,
+  # it ignores the "install-scripts" directive, which is commonly used in ROS
+  # to install binaries to "$out/lib/<package name>".
   # https://github.com/colcon/colcon-core/blob/0.12.1/colcon_core/task/python/build.py#L84
   format = "other";