The backport tool is for backporting merged pull request in GitHub. It takes a specific code change or feature that was developed on a newer version / commit in the codebase and apply's it to an older version of the same codebase (e.g. a release branch).
This tool is currently being used for Sourcegraph releases in order to backport changes from the main branch to a minor version branch and replace the manual cherry-picking process.
It is developed in sourcegraph/backport.
Backporting is how you move changes from main into a release branch i.e. X.X.x.
To backport to a specific branch, simply attach the relevant backport label on Github to your pull request corresponding to the desired target branch. Once your original pull request is merged a GitHub action will attempt the cherry-pick and if successful another pull request will be opened to backport your change into the target branch.
For example a PR labelled: backport X.X.x
A PR like this will be generated:
Backport labels can be applied after merge, so you don't need to worry if you didn't include the label before you merged your pull request.
It is your responsibility to ensure any backports that you open are merged before a release is cut. Release support will get a notification that backports are opened as a release blocker, but the best case scenario is all backports are closed promptly. A good practice it to backport and merge your change if necessary as soon as possible after merging into main.