[FEATURE]: Upgrade Gazebo from Garden to Harmonic

[evan-palmer]

Feature Type

Changing existing functionality in the BlueROV2 driver

Problem Description

The current LTS (Jazzy) and Rolling use Gazebo Harmonic instead of Gazebo Garden.

Feature Description

Upgrade the main and jazzy branches to use this version of Gazebo.

Alternative Solutions

N/A

Additional Context

No response

[evan-palmer]

This is currently being blocked by mavlink/mavros#1958. Once merged, we can resolve this issue.

[evan-palmer]

Harmonic is now the recommended version for Humble and Iron. Might be good to upgrade those first while waiting for Jazzy support

[amarburg]

#220 upgrades Rolling to Harmonic. I could break just the upgrade to Harmonic into a separate PR which you could propagate to Humble and Iron (leaving the Rolling / Noble - specific changes in the existing PR)

[evan-palmer]

I just double-checked this, and I was wrong. Hypothetically, the backport should still work (ros_gz is already being built from source to support Garden), but I'm contemplating discontinuing the ros_gz source build in future releases to reduce some of the maintenance and build times (and also make things more stable). If we move to using the ros_gz binaries in #220, then we will probably want to keep separate PRs.

[amarburg]

So here's a merge of the ROS-Gazebo compatibility matrix and the ROS-Gazebo-ros_gz matrix:

ROS2 Version	Gazebo Version	ROS2-Gazebo Compat	ros_gz binaries?
Humble	Fortress	Recommended	https://packages.ros.org/
Humble	Garden	Possible	gazebo packages
Humble	Harmonic	Possible	gazebo packages
Iron	Fortress	Recommended	https://packages.ros.org/
Iron	Garden	Possible	From source
Iron	Harmonic	Possible	From source
Jazzy	Garden	Possible	From source
Jazzy	Harmonic	Recommended	https://packages.ros.org/
Rolling	Fortress	Recommended	https://packages.ros.org/
Rolling	Garden	Possible	From source
Rolling	Harmonic	Possible	From source

Based on the spotty availability of binaries, what's the desirable endpoint for blue?

Here's where we are now:

ROS2 Version	Gazebo Version	ros_gz
Humble	Garden	From source
Iron	Garden	From source
Jazzy	Harmonic (PR work-in-progress here)	From source (but packages are available)
Rolling	Garden (or Harmonic via PR #220)	From source (packages available for Harmonic)

I assume Rolling is converging with Jazzy (i.e. Harmonic will soon be the preferred version)?

[evan-palmer]

Here is what I'm thinking:

ROS 2 Version	Gazebo Version	ros_gz binaries
Humble	Harmonic	packages.osrfoundation.org
Iron	Harmonic	packages.osrfoundation.org
Jazzy	Harmonic	packages.ros.org
Rolling	Harmonic	Open to discuss

The reason that I am undecided on Rolling is because it may be nice to switch to new versions of Gazebo as they come out, but I am open to discuss that. Here are the docs on the Iron/Humble/Jazzy Harmonic installation.

[amarburg]

Hm. So I'm stuck on how to implement the switching between ros_gz sources from a git-mergify point of view. How about:

1. This PR switches the default to harmonic. Apply it to main (aka rolling) and propagate to jazzy iron and humble.
2. Targeted commit to jazzy which removes the source build for ros_gz and instead installs from packages.ros.org
3. Targeted commit to iron which removes the source build and instead installs from osrffoundation.org

This should work for iron and humble at least. Jazzy is still broken per #168 , and Rolling still broken per #220