Release procedure

This page gives an overview of how Safir releases are made. This information is only useful for maintainers.

Safir’s releases are largely automated through GitHub Actions (see the ci.yaml workflow file for details). When a semantic version tag is pushed to GitHub, Safir is released to PyPI with that version. Similarly, documentation is built and pushed for each version (see https://safir.lsst.io/v).

Regular releases

Regular releases happen from the master branch after changes have been merged. From the master branch you can release a new major version (X.0.0), a new minor version of the current major version (X.Y.0), or a new patch of the current major-minor version (X.Y.Z). See Backport releases to patch an earlier major-minor version.

Release tags are semantic version identifiers following the PEP 440 specification.

1. Change log and documentation

Each PR should include updates to the change log. If the change log or documentation needs additional updates, now is the time to make those changes through the regular branch-and-PR development method against the master branch.

In particular, replace the “Unreleased” section headline with the semantic version and date. See Updating the change log in the Developer guide for details.

2. Tag the release

At the HEAD of the master branch, create and push a tag with the semantic version:

git tag -s X.Y.Z -m "X.Y.Z"
git push --tags

The tag must follow the PEP 440 specification since Safir uses setuptools_scm to set version metadata based on Git tags. In particular, don’t prefix the tag with v.

The ci.yaml GitHub Actions workflow uploads the new release to PyPI and documentation to https://safir.lsst.io.

Backport releases

The regular release procedure works from the main line of development on the master Git branch. To create a release that patches an earlier major or minor version, you need to release from a release branch.

Creating a release branch

Release branches are named after the major and minor components of the version string: X.Y. If the release branch doesn’t already exist, check out the latest patch for that major-minor version:

git checkout X.Y.Z
git checkout -b X.Y
git push -u

Developing on a release branch

Once a release branch exists, it becomes the “master” branch for patches of that major-minor version. Pull requests should be based on, and merged into, the release branch.

If the development on the release branch is a backport of commits on the master branch, use git cherry-pick to copy those commits into a new pull request against the release branch.

Releasing from a release branch

Releases from a release branch are equivalent to regular releases, except that the release branch takes the role of the master branch.