Make FindPackage substitutions a Path to get operator /

[emersonknapp]

Description

Part of robograph-project/planning#38
Depends on ros2/launch#914

Make FindPackage{X} substitutions a subclass of PathSubstitution to get the path join operator for free.

Lets you change:

PathSubstitution(FindPackageShare('my_pkg')) / 'launch' / 'my_launch.yaml'
# or
PathJoinSubstitution([FindPackageShare('my_pkg'), 'launch', 'my_launch.yaml'])

into

FindPackageShare('my_pkg') / 'launch' / 'my_launch.yaml'

Is this user-facing behavior change?

New user-facing capability, does not affect existing behavior

Did you use Generative AI?

no

Additional Information

[ahcorde]

Pulls: ros2/launch#914, #494
Gist: https://gist.githubusercontent.com/ahcorde/1d8541d31501406682d13767e15e788e/raw/cb7660853dbaea155933d8576f146a1a0d5953d6/ros2.repos
BUILD args: --packages-above-and-dependencies launch launch_ros test_launch_ros
TEST args: --packages-above launch launch_ros test_launch_ros
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/17368

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[emersonknapp]

Pulls: ros2/launch#914, #494
Gist: https://gist.githubusercontent.com/emersonknapp/2c725d3e9c99a8e2cd15f567470d1ada/raw/cb7660853dbaea155933d8576f146a1a0d5953d6/ros2.repos
BUILD args: --packages-above-and-dependencies launch launch_ros test_launch_ros
TEST args: --packages-above launch launch_ros test_launch_ros
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/17378

• Linux
• Linux-aarch64
• Linux-rhel
  • 
• Windows