Release 8.20

[proux01]

Release checklist

When the release managers for version X.X get nominated

• Create a new issue to track the release process where you can copy-paste the present checklist from dev/doc/release-process.md.
• Decide the release calendar with the team (date of branching, preview and final release).
• Create a wiki page that you link to from https://github.com/coq/coq/wiki/Release-Plan with this information and the link to the issue.

About one month before the branching date

• Create both the upcoming final release (X.X.0) and the following major release (Y.Y+rc1) milestones if they do not already exist.
• Send an announcement of the upcoming branching date on Coqdev + the Coq development category on Discourse (coqdev@inria.fr + coq+coq-development@discoursemail.com) and ask people to remove from the X.X+rc1 milestone any feature and clean up PRs that they already know won't be ready on time.
• In a PR on master, call dev/tools/update-compat.py with the --release flag; this sets up Coq to support three -compat flag arguments including the upcoming one (instead of four). To ensure that CI passes, you will have to decide what to do about all test-suite files that mention -compat U.U or Coq.Compat.CoqUU (which is no longer valid, since we only keep compatibility against the two previous versions), and you may have to ping maintainers of projects that are still relying on the old compatibility flag so that they fix this.
• Make sure that this change is merged in time for the branching date.
• Prepare a PR on master (not yet to be merged) changing the version name to the next major version and both magic numbers in tools/configure/configure.ml. For example, for 8.5, the version name will be 8.5+alpha while the magic numbers will end with 80490.
  Additionally, in the same commit, update the compatibility infrastructure, which consists of invoking dev/tools/update-compat.py with the --master flag.
  Note that the update-compat.py script must be run twice: once in preparation of the release with the --release flag (see earlier in this section) and once on the branching date with the --master flag to mark the start of the next version.
  This PR should be opened before the branching date to have time to deal with CI issues, but should not be merged until branching.

On the branching date

• Merge the above PR and create the vX.X branch from the last merge commit before this one (using this name will ensure that the branch will be automatically protected).
• Set the next major version alpha tag using git tag -s. The VY.Y+alpha tag marks the first commit to be in master and not in the vX.X release branch. Note that this commit is the first commit in the first PR merged in master, not the merge commit for that PR. Therefore, if you proceeded as described above, this should be the commit updating the version, magic numbers and compatibility infrastructure. After tagging, double-check that git describe picks up the tag you just made (if not, you tagged the wrong commit).
• Push the new tag with git push upstream VY.Y+alpha --dry-run (remove the --dry-run and redo if everything looks OK).
• Start a new "classic" project to track PR backporting. The project should have a Request X.X+rc1 inclusion column for the PRs that were merged in master that are to be considered for backporting, and a Shipped in X.X+rc1 columns to put what was backported. A message to @coqbot in the milestone description tells it to automatically add merged PRs to the Request ... inclusion column and backported PRs to the Shipped in ... column. See previous milestones for examples. When moving to the next milestone (e.g. X.X.0), you can clear and remove the Request X.X+rc1 inclusion column and create new Request X.X.0 inclusion and Shipped in X.X.0 columns.
  The release manager is the person responsible for merging PRs that target the release branch and backporting appropriate PRs (mostly safe bug fixes, user message improvements and documentation updates) that are merged into master.
• Pin the versions of libraries and plugins in dev/ci/ci-basic-overlay.sh to use commit hashes. You can use the dev/tools/pin-ci.sh script to do this semi-automatically.
• In a PR on master to be backported, add a new link to the 'versions' list of the refman (in html_context in doc/sphinx/conf.py).
• Ping @Zimmi48 and @erikmd to set up the infrastructure to have alpha Docker images built for the branch.

In the days following the branching

• Make sure that all the last feature PRs that you want to include in the release are finished and backported quickly and clean up the milestone. We recommend backporting as few feature PRs as possible after branching. In particular, any PR with overlays will require manually bumping the pinned commits when backporting.
• Delay non-blocking issues to the appropriate milestone and ensure blocking issues are solved. If required to solve some blocking issues, it is possible to revert some feature PRs in the release branch only (but in this case, the blocking issue should be postponed to the next major release instead of being closed).
• Once the final list of features is known, in a PR on master to be backported, generate the release changelog by calling dev/tools/generate-release-changelog.sh and include it in a new section in doc/sphinx/changes.rst.
  The script automatically reorders the entries to show first the Changed, then the Removed, Deprecated, Added and last the Fixed. Manual adjustement is still needed when multiple entries are combined in a single changelog file.
• Ping the development coordinator (@mattam82) to get him started on writing the release summary.
  The dev/tools/list-contributors.sh script computes the number and list of contributors between Coq revisions. Typically used with VX.X+alpha..vX.X to check the contributors of version VX.X.
  Note that this script relies on .mailmap to merge multiple identities. If you notice anything incorrect while using it, use the opportunity to fix the .mailmap file. Same thing if you want to have the full name of a contributor shown instead of a pseudonym.
• Put the branch name in the CACHEKEY variables in .gitlab-ci.yml (for instance old_ubuntu_lts-V2022-05-20-c34331afa5 to "old_ubuntu_lts-v8.16-V2022-05-20-c34331afa5) to indicate that it shouldn't be cleaned up even once it gets old. This should be done after all PRs touching the CACHEKEY variables have been merged.

For each release (preview, final, patch-level)

• Ensure that there exists a milestone for the following version.
• Ensure the release changelog has been merged (the release summary is required for the final release).
• In a PR against vX.X (for testing):
  • Update the version number in tools/configure/configure.ml.
  • Only update the magic numbers for the final release.
  • Set is_a_released_version to true.
• Set the tag VX.X... using git tag -s.
• Push the new tag with git push upstream VX.X... --dry-run (remove the --dry-run and redo if everything looks OK).
• Set is_a_released_version to false (if you forget about it, you'll be reminded by the test-suite failing whenever you try to backport a PR with a changelog entry).
• Close the milestone.
• Send an e-mail on coqdev + coq-club + the Coq announcement category on Discourse (coqdev@inria.fr + coq-club@inria.fr + coq+announcements@discoursemail.com) announcing that the tag has been set so that package managers can start preparing package updates (including a coq-bignums compatible version), after which library authors can safely start preparing compatible releases.
• In particular, ensure that someone is working on providing an opam package (either in the main ocaml/opam-repository for standard releases or in the core-dev category of the coq/opam-coq-archive for preview releases.
• Make sure to cc @ejgallego to ensure that a release for coq-serapi is available in opam-repository (typically, using dune-release tag and dune-release).
• Make sure to cc @proux01 to ensure that a coq-bignums opam package is available in extra-dev or released, respectively.
• Make sure to cc @erikmd to ensure that the necessary configuration is ready to release the Docker images in coqorg/coq (gathering coq, coq-bignums, and coq-serapi opam packages).
• Publish a release on GitHub with the PDF version of the reference manual attached. The PDF can be recovered from the artifacts of the doc:refman-pdf job from continuous integration. Also attach a tar.gz archive of the sources (to ensure a stable hash, you can copy the archive autogenerated by github when the release is published).
• If pinged by opam package providers in pull requests to ocaml/opam-repository, transfer any changes to opam packages required by opam-repository CI (such as missing dependencies) to the corresponding package definitions in the Coq repository.

For each non-preview release

• Modify the version number in the file incl/macros.html on the website.

Only for the final release of each major version

• Ping @Zimmi48 to publish a new version on Zenodo.
  TODO: automate this with coqbot.

This is now delegated to the platform maintainers

• Sign the Windows and MacOS packages and upload them on GitHub.
  • The Windows packages must be signed by the Inria IT security service. They should be sent as a link to the binary (via filesender for example) together with its SHA256 hash in a signed e-mail to dsi.securite @ inria.fr putting @maximedenes in carbon copy.
  • The MacOS packages should be signed with our own certificate.
  • The Snap package has to be built and uploaded to the snap store by running a platform CI job manually.
    Then ask a Platform maintainer with access to the store to publish the upload or give you access so that you can do it yourself.
• Announce the release to Coq-Club and Discourse (coq-club@inria.fr + coq+announcements@discoursemail.com).