register rmw python extensions separately

* register rmw python extensions separately

* setup the ament_index in the build space for testing

* updates to use new ament_index syntax

* escape ; as \; when passing a PATH list as an env var on Windows

* just append the build folder's ament index as a work around

rclpy/CMakeLists.txt

@@ -77,6 +77,14 @@ macro(target)
     ${PythonExtra_INCLUDE_DIRS}
   )
 
+  # make an entry in the ament index for each rmw implementation for which
+  # a rclpy Python extension is built
+  # this is used in the Python code to avoid trying to import a Python
+  # extension for rmw implementations which do not have one
+  ament_index_register_resource("rmw_python_extension"
+    PACKAGE_NAME ${rmw_implementation}
+  )
+
   install(TARGETS ${PROJECT_NAME}${target_suffix}
     DESTINATION "${PYTHON_INSTALL_DIR}/${PROJECT_NAME}")
 endmacro()
@@ -88,9 +96,17 @@ if(AMENT_ENABLE_TESTING)
   ament_lint_auto_find_test_dependencies()
 
   rosidl_generator_py_get_typesupports(_typesupport_impls)
+  ament_index_get_prefix_path(ament_index_build_path SKIP_AMENT_PREFIX_PATH)
+  # Get the first item (it will be the build space version of the build path).
+  list(GET ament_index_build_path 0 ament_index_build_path)
+  if(WIN32)
+    # On Windows prevent CMake errors and prevent it being evaluated as a list.
+    string(REPLACE "\\" "/" ament_index_build_path "${ament_index_build_path}")
+  endif()
   if(NOT "${_typesupport_impls} " STREQUAL " ")
     ament_add_nose_test(rclpytests test
       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}"
+      APPEND_ENV AMENT_PREFIX_PATH=${ament_index_build_path}
     )
   endif()
 endif()

rclpy/rclpy/impl/rmw_implementation_tools.py

@@ -24,17 +24,13 @@
 __selected_rmw_implementation = None
 __rmw_implementation_module = None
 
+AMENT_INDEX_NAME = 'rmw_python_extension'
+
 
 def reload_rmw_implementations():
     """(Re)Load the available rmw implementations by inspecting the ament index."""
     global __rmw_implementations
-    __rmw_implementations = sorted(ament_index_python.get_resources('rmw_implementation').keys())
-
-    # Remove implementations that are being filtered for in the rclpy CMakeLists so
-    # that they cannot be selected
-    __rmw_implementations = [
-        rmw_impl for rmw_impl in __rmw_implementations
-        if rmw_impl not in ['rmw_connext_dynamic_cpp', 'rmw_fastrtps_cpp']]
+    __rmw_implementations = sorted(ament_index_python.get_resources(AMENT_INDEX_NAME).keys())
     return __rmw_implementations
 
 

rclpy/test/test_select_rmw_implementation.py

@@ -43,18 +43,7 @@ def func_import_each_available_rmw_implementation(rmw_implementation):
     assert(rmw_implementation in rmw_implementations)
 
     select_rmw_implementation(rmw_implementation)
-    try:
-        rclpy.init([])
-    except ImportError as exc:
-        if "No module named 'rclpy._rclpy__" in '{0}'.format(exc):
-            # Not all rmw implementations generate a Python implementation.
-            # TODO(wjwwood): prune get_rmw_implementations by
-            #   implementations that have generated a Python implementation
-            #   (probably use a separate ament index entry).
-            print("Failed to import rmw implementation '{0}', ignoring."
-                  .format(rmw_implementation), file=sys.stderr)
-            return ctypes.c_bool(True)
-        raise
+    rclpy.init([])
 
     set_rmw = rclpy.get_rmw_implementation_identifier()
 
@@ -93,18 +82,7 @@ def func_select_rmw_implementation_by_environment(rmw_implementation):
     rmw_implementations = get_rmw_implementations()
     assert(os.environ['RCLPY_IMPLEMENTATION'] in rmw_implementations)
 
-    try:
-        rclpy.init([])
-    except ImportError as exc:
-        if "No module named 'rclpy._rclpy__" in '{0}'.format(exc):
-            # Not all rmw implementations generate a Python implementation.
-            # TODO(wjwwood): prune get_rmw_implementations by
-            #   implementations that have generated a Python implementation
-            #   (probably use a separate ament index entry).
-            return ctypes.c_bool(True)
-            print("Failed to import rmw implementation '{0}', ignoring."
-                  .format(rmw_implementation), file=sys.stderr)
-        raise
+    rclpy.init([])
 
     set_rmw = rclpy.get_rmw_implementation_identifier()