Hello Gazebo Community!
TL;DR: For Gazebo development we’re moving from forward ports to backports to improve developer velocity. New Gazebo features should target Harmonic branches. We’re also changing the duration of our support windows, with the latest release receiving a one year active support window, and a two or five year general support window.
The Gazebo team is making changes to our new feature development policy to optimize our resources and reduce our overhead. Previously, our policy was to add new features to the oldest stable release possible and forward port to all newer releases. For example, if a user wanted to add a new feature to gz-sim, they were encouraged to target the ign-gazebo3 branch, which corresponds to the Citadel release. Once the feature is merged, the Gazebo team takes the responsibility of forward porting that feature to Fortress, Garden, and Harmonic. As you can imagine, this has created a lot of overhead on the Gazebo team, especially since the Ignition->Gazebo rename. Adding new features to old branches also means we have to use older APIs in new code, which keeps the codebase from progressing with newer technologies. Lastly, targeting old branches is confusing for new contributors, as this is not common practice in the open source community.
In the new policy we will have two support windows:
- Active support window: window of time in which a given release gets new features and bug fixes. All new (both LTS and non-LTS) releases will have a one year active support window.
- General support window: window of time in which a given release gets bug fixes and potential backports of new features on a best-effort basis. This is five years for LTS releases and two years for non-LTS releases.
After a new release is made, it will have a one year active support window. During this period, the Gazebo team and community contributors are encouraged to add new features to that release[1]. If the new feature can be backported to older releases without much overhead, the Gazebo team or the author of the feature is encouraged to backport it to older releases that are still in the general support window. Note that since there is one release per year, the active support window is applicable to only one release at a time. As of this writing, Harmonic is the release in the active support window.
Going forward, please target the latest released branch when creating a new feature pull request. This is also the default branch, so GitHub should automatically select it when creating a new pull request.
The Gazebo Dev Team
ABI breaking releases will still need to go into
mainbranches (next release). ↩︎