Fix cross-compiling ROS2 packages.

distros/ament-cmake-core-setup-hook/default.nix

@@ -2,8 +2,5 @@
 
 makeSetupHook {
   name = "ament-cmake-core-setup-hook";
-  substitutions = {
-    python_major = python.sourceVersion.major;
-    python_executable = python.pythonForBuild.interpreter;
-  };
+  substitutions.python_executable = python.pythonForBuild.interpreter;
 } ./setup-hook.sh

distros/ament-cmake-core-setup-hook/setup-hook.sh

@@ -28,6 +28,6 @@ _amentCmakeCorePreConfigureHook() {
   # and just bloats the closure.
   cmakeFlags+=" -DAMENT_CMAKE_ENVIRONMENT_PARENT_PREFIX_PATH_GENERATION:BOOL=OFF"
   # Point CMake at build platform Python so it can run it at build time
-  cmakeFlags+=" -DPython@python_major@_EXECUTABLE:FILEPATH=@python_executable@"
+  cmakeFlags+=" -DPython3_EXECUTABLE:FILEPATH=@python_executable@"
 }
 preConfigureHooks+=(_amentCmakeCorePreConfigureHook)

distros/distro-overlay.nix

@@ -267,6 +267,15 @@ let
 
     pr2-tilt-laser-interface = patchBoostSignals rosSuper.pr2-tilt-laser-interface;
 
+    python-cmake-module = rosSuper.python-cmake-module.overrideAttrs ({ ... }: let
+      python = rosSelf.python;
+    in {
+      pythonExecutable = python.pythonForBuild.interpreter;
+      pythonLibrary = "${python}/lib/lib${python.libPrefix}.so";
+      pythonIncludeDir = "${python}/include/${python.libPrefix}";
+      setupHook = ./python-cmake-module-setup-hook.sh;
+    });
+
     python-qt-binding = rosSuper.python-qt-binding.overrideAttrs ({
       propagatedNativeBuildInputs ? [],
       postPatch ? "", ...
@@ -291,6 +300,30 @@ let
 
     roscpp = patchBoostSignals rosSuper.roscpp;
 
+    rosidl-generator-py = rosSuper.rosidl-generator-py.overrideAttrs ({
+      postPatch ? "",
+      patches ? [], ...
+    }: let
+      python = rosSelf.python;
+    in {
+      patches = patches ++ [
+        # Remove stray numpy import in template
+        # https://github.com/ros2/rosidl_python/pull/185
+        (self.fetchpatch {
+          url = "https://github.com/ros2/rosidl_python/commit/bf866089baeb918834d9d16e05668d9f28887b87.patch";
+          hash = "sha256-tOb0t50TbV29+agDupm5XUZJJErfaujgIRtmb2vZxWo=";
+          stripLen = 1;
+        })
+      ];
+      # Fix finding NumPy headers
+      postPatch = postPatch + ''
+        substituteInPlace cmake/rosidl_generator_py_generate_interfaces.cmake \
+         --replace '"import numpy"' "" \
+         --replace 'numpy.get_include()' "'${python.pkgs.numpy}/${python.sitePackages}/numpy/core/include'"
+      '';
+      setupHook = ./rosidl-generator-py-setup-hook.sh;
+    });
+
     rmw-implementation = rosSuper.rmw-implementation.overrideAttrs ({
       propagatedBuildInputs ? [], ...
     }: {

distros/python-cmake-module-setup-hook.sh

@@ -0,0 +1,6 @@
+_pythonCmakeModulePreConfigureHook() {
+  cmakeFlags+=" -DPYTHON_EXECUTABLE=@pythonExecutable@"
+  cmakeFlags+=" -DPYTHON_LIBRARY=@pythonLibrary@"
+  cmakeFlags+=" -DPYTHON_INCLUDE_DIR=@pythonIncludeDir@"
+}
+preConfigureHooks+=(_pythonCmakeModulePreConfigureHook)

distros/rosidl-generator-py-setup-hook.sh

@@ -0,0 +1,6 @@
+_rosidlGeneratorPyPreConfigureHook() {
+  # Prevent "RPATH of binary ... contains a forbidden reference to /build/"
+  # when cross-compiling
+  cmakeFlags+=" -DCMAKE_SKIP_BUILD_RPATH:BOOL=ON"
+}
+preConfigureHooks+=(_rosidlGeneratorPyPreConfigureHook)