Suggest adding exec_depend on ros2launch for packages with launch files

[christophebedard]

This is a change suggested here after we realized that the launch frontends may not get built if your
package doesn't depend on them (almost none of the common CLI/launch packages do): ros2/launch#516 (comment)

I don't know if we have it documented anywhere, but we should recommend depending on ros2launch always, it seems. Otherwise important parts will not be included.

Note that the last line in this proposed change isn't currently valid. Depending on ros2launch will only ensure launch_xml/launch_yaml are built after this PR (or an equivalent PR) is merged: ros2/launch_ros#256

I couldn't really find a perfect place to put this note, but this seemed like an okay spot.

Signed-off-by: Christophe Bedard [email protected]

[audrow]

I think this is a good note to add. I agree it's not clear where to put it. What would you think about adding it at the end of the setup section in the creating launch files tutorial?

[christophebedard]

I think this is a good note to add. I agree it's not clear where to put it. What would you think about adding it at the end of the setup section in the creating launch files tutorial?

I don't really mind, but this tutorial mostly shows how to create a standalone launch file so it feels kind of rushed to mention this at the very beginning. There's a note that mentions having a launch file under a specific package here: https://docs.ros.org/en/rolling/Tutorials/Launch-Files/Creating-Launch-Files.html#ros2-launch. What do you think about putting this new note after that one?

[audrow]

https://docs.ros.org/en/rolling/Tutorials/Launch-Files/Creating-Launch-Files.html#ros2-launch. What do you think about putting this new note after that one?

Sorry to fall off. That sounds good to me. I think this spot is better because it comes into the user's awareness sooner than later.

[christophebedard]

I moved it in 45e7e09 and added a link to the launch file formats guide in 6e5a7c8.

[audrow]

@Mergifyio backport galactic foxy

[mergify]

backport galactic foxy

✅ Backports have been created

• #2138 Suggest adding exec_depend on ros2launch for packages with launch files (backport #1786) has been created for branch galactic
• #2139 Suggest adding exec_depend on ros2launch for packages with launch files (backport #1786) has been created for branch foxy

[audrow]

Thanks for the PR, @christophebedard!