Release procedure for HPX¶

Below is a step by step procedure for making an HPX release. We aim to produce two releases per year: one in March-April, and one in September-October.

This is a living document and may not be totally current or accurate. It is an attempt to capture current practices in making an HPX release. Please update it as appropriate.

One way to use this procedure is to print a copy and check off the lines as they are completed to avoid confusion.

Notify developers that a release is imminent.
For minor and major releases: create and check out a new branch at an appropriate point on master with the name release-major.minor.X. major and minor should be the major and minor versions of the release. For patch releases: check out the corresponding release-major.minor.X branch.
Write release notes in docs/sphinx/releases/whats_new_$VERSION.rst. Keep adding merged PRs and closed issues to this until just before the release is made. Use tools/generate_pr_issue_list.sh to generate the lists. Add the new release notes to the table of contents in docs/sphinx/releases.rst.
Build the docs, and proof-read them. Update any documentation that may have changed, and correct any typos. Pay special attention to:
- $HPX_SOURCE/README.rst
  - Update grant information
- docs/sphinx/releases/whats_new_$VERSION.rst
- docs/sphinx/about_hpx/people.rst
  - Update collaborators
  - Update grant information
This step does not apply to patch releases. For both APEX and libCDS:
- Change the release branch to be the most current release tag available in the APEX/libCDS git_external section in the main CMakeLists.txt. Please contact the maintainers of the respective packages to generate a new release to synchronize with the HPX release (APEX, libCDS).
Make sure HPX_VERSION_MAJOR/MINOR/SUBMINOR in CMakeLists.txt contain the correct values. Change them if needed.
This step does not apply to patch releases. Remove features which have been deprecated for at least 2 releases. This involves removing build options which enable those features from the main CMakeLists.txt and also deleting all related code and tests from the main source tree.

The general deprecation policy involves a three-step process we have to go through in order to introduce a breaking change:
1. First release cycle: add a build option that allows for explicitly disabling any old (now deprecated) code.
2. Second release cycle: turn this build option OFF by default.
3. Third release cycle: completely remove the old code.
The main CMakeLists.txt contains a comment indicating for which version the breaking change was introduced first. In the case of deprecated features which don’t have a replacement yet, we keep them around in case (like Vc for example).
Update the minimum required versions if necessary (compilers, dependencies, etc.) in building_hpx.rst.
Verify that the Jenkins setups for the release branch on Rostam and Piz Daint are running and do not display any errors.
Repeat the following steps until satisfied with the release.
1. Change HPX_VERSION_TAG in CMakeLists.txt to -rcN, where N is the current iteration of this step. Start with -rc1.
2. Create a pre-release on GitHub using the script tools/roll_release.sh. This script automatically tag with the corresponding release number. The script requires that you have the STE||AR Group signing key.
3. This step is not necessary for patch releases. Notify hpx-users@stellar-group.org and stellar@cct.lsu.edu of the availability of the release candidate. Ask users to test the candidate by checking out the release candidate tag.
4. Allow at least a week for testing of the release candidate.
  - Use git merge when possible, and fall back to git cherry-pick when needed. For patch releases git cherry-pick is most likely your only choice if there have been significant unrelated changes on master since the previous release.
  - Go back to the first step when enough patches have been added.
  - If there are no more patches, continue to make the final release.
Update any occurrences of the latest stable release to refer to the version about to be released. For example, quickstart.rst contains instructions to check out the latest stable tag. Make sure that refers to the new version.
Add a new entry to the RPM changelog (cmake/packaging/rpm/Changelog.txt) with the new version number and a link to the corresponding changelog.
Change HPX_VERSION_TAG in CMakeLists.txt to an empty string.
Add the release date to the caption of the current “What’s New” section in the docs, and change the value of HPX_VERSION_DATE in CMakeLists.txt.
Create a release on GitHub using the script tools/roll_release.sh. This script automatically tag the with the corresponding release number. The script requires that you have the STE||AR Group signing key.
Update the websites (hpx.stellar-group.org, stellar-group.org and stellar.cct.lsu.edu). You can login on wordpress through this page <https://hpx.stellar-group.org/wp-login.php>. You can update the pages with the following:
- Update links on the downloads page. Link to the release on GitHub.
- Documentation links on the docs page (link to generated documentation on GitHub Pages). Follow the style of previous releases.
- A new blog post announcing the release, which links to downloads and the “What’s New” section in the documentation (see previous releases for examples).
Merge release branch into master.
Post-release cleanup. Create a new pull request against master with the following changes:
1. Modify the release procedure if necessary.
2. Change HPX_VERSION_TAG in CMakeLists.txt back to -trunk.
3. Increment HPX_VERSION_MINOR in CMakeLists.txt.
Update Vcpkg (https://github.com/Microsoft/vcpkg) to pull from latest release.
- Update version number in CONTROL
- Update tag and SHA512 to that of the new release
Update spack (https://github.com/spack/spack) with the latest HPX package.
- Update version number in hpx/package.py and SHA256 to that of the new release
Announce the release on hpx-users@stellar-group.org, stellar@cct.lsu.edu, allcct@cct.lsu.edu, faculty@csc.lsu.edu, faculty@ece.lsu.edu, xpress@crest.iu.edu, the HPX Slack channel, the IRC channel, Sonia Sachs, our list of external collaborators, isocpp.org, reddit.com, HPC Wire, Inside HPC, Heise Online, and a CCT press release.
Beer and pizza.