enso/docs/distribution/release-policy.md

layout	title	category	tags	order
developer-doc	Release Policy	distribution	distribution release release-policy policy	3

Release Policy

As an open-source project and programming language, it is incredibly important that we have a well-defined release policy. This document defines said policy.

• Versioning
  • Launcher Versioning
• Release Branches
• Release Workflow
  • Tag Naming
  • GitHub Releases
  • Release Notes
• Version Support
• Working on the Current Release
• Backporting Fixes

Versioning

Releases of Enso are versioned using semantic versioning. Where a.b.c-tag is the version string, a is the major version, b, is the minor version, c is the patch version, and tag is additional metadata, the following hold:

• Breaking changes to language behaviour or the public API will result in a major version increase.
• Addition of functionality in a backwards-compatible manner will result in a minor version increase.
• Backwards-compatible bug fixes will result in a patch version increase.
• The tag will indicate pre-release or beta versions, and will increase when any pre-release change is made. These are not intended to be stable.

Launcher Versioning

The launcher is released alongside Enso releases, so the launcher version is tied to the Enso version that it is released with.

Release Branches

A release branch in the Enso repository is a branch prefixed with release/. Release branches obey the following rules:

• One release branch exists per major version, and is named release/n.x, where n is the major version, and the rest is literal.
• A release branch must contain tags corresponding to released versions of Enso. Once a release has been made, no further changes may be made to that release.
• A tagged release must contain a CHANGELOG file that describes the changes contained in that release.

It should be noted that general development still takes place on the main branch of the repository.

Release Workflow

Cutting a release for Enso proceeds as follows:

1. If no release branch exists for the current major version, one should be created.
2. Release notes should be made up to date.
3. A commit representing the release should be tagged, and the tag pushed to GitHub.
4. CI will create a draft release for this tag, as well as build and upload the appropriate artefacts.
5. The release notes for the version being released should be copied into the release body on GitHub.
6. The release must be verified by two members of the engine team, and the QA team.
7. Once approval has been gained from these members, the release may be made official.

Tag Naming

Tags for releases are named as follows enso-version, where version is the semver string (see versioning) representing the version being released.

GitHub Releases

A release is considered official once it has been made into a release on GitHub. Once official, a release may not be changed in any way, except to mark it as broken.

Manifest File

Each GitHub release contains an asset named manifest.yaml which is a YAML file containing metadata regarding the release. The manifest is also included in the root of an Enso version package. It has at least the following fields:

• minimum-launcher-version - specifies the minimum version of the launcher that should be used with this release of Enso,
• graal-vm-version - specifies the exact version of GraalVM that should be used with this release of Enso,
• graal-java-version - as GraalVM versions may have different variants for different Java versions, this specifies which variant to use.

It can also contain the following additional fields:

• jvm-options - specifies a list of options that should be passed to the JVM running the engine. These options can be used to fine-tune version specific optimization settings etc. Each option must have a key called value which specifies what option should be passed. That value can include a variable $enginePackagePath which is substituted with the absolute path to the root of the engine package that is being launched. Optionally, the option may define os which will restrict this option only to the provided operating system. Possible os values are linux, macos and windows.
• broken - can be set to true to mark this release as broken. This field is never set in a release. Instead, when the launcher is installing a release marked as broken using the broken file, it adds this property to the manifest to preserve that information.

For example:

minimum-launcher-version: 0.0.1
graal-vm-version: 20.2.0
graal-java-version: 11
jvm-options:
  - value: "-Dpolyglot.engine.IterativePartialEscape=true"
  - value: "-Dtruffle.class.path.append=$enginePackagePath\\component\\runtime.jar"
    os: "windows"
  - value: "-Dtruffle.class.path.append=$enginePackagePath/component/runtime.jar"
    os: "linux"
  - value: "-Dtruffle.class.path.append=$enginePackagePath/component/runtime.jar"
    os: "macos"

The minimum-launcher-version should be updated whenever a new version of Enso introduces changes that require a more recent launcher version. This value is stored in distribution/manifest.template.yaml and other values are added to this template at build time.

Release Assets Structure

Each release contains a build of the Enso engine and native launcher binaries for each supported platform. Moreover, for convenience, it should include bundles containing native launcher binaries and the latest engine build for each platform. So each release should contain the following assets:

• enso-bundle-<version>-linux-amd64.tar.gz
• enso-bundle-<version>-macos-amd64.tar.gz
• enso-bundle-<version>-windows-amd64.zip
• enso-engine-<version>-linux-amd64.tar.gz
• enso-engine-<version>-macos-amd64.tar.gz
• enso-engine-<version>-windows-amd64.zip
• enso-launcher-<version>-linux-amd64.tar.gz
• enso-launcher-<version>-macos-amd64.tar.gz
• enso-launcher-<version>-windows-amd64.zip
• manifest.yaml

Marking a Release as Broken

We intend to never delete a release from GitHub, as users may have projects that depend on specific versions of Enso. Instead, we provide a mechanism for marking releases as broken that works as follows:

• An empty file named broken is uploaded to the release.
• The release description is edited to visibly mark the release as broken.

A broken release is one that must not be downloaded by the launcher unless a project specifies an exact version match, and it must not be used in new projects by the launcher unless explicitly specified by the user as an exact version match.

Release Notes

Release notes should contain a summary of the changes made between the last release and the current release. They should follow the template given below:

# Enso x.y.z (YYYY-MM-DD)

## Language

- A list of language-level changes.

## Type System

- A list of type-system changes.

## Interpreter

- A list of changes to the Enso interpreter.

## Runtime

- A list of changes to the Enso runtime.

## Tooling

- A list of changes to the Enso language tooling.

## Libraries

- A list of changes to the Enso core libraries.

## Stabilised Features

- A list of stabilised APIs and/or features.

## Misc

- A list of miscellaneous changes.

## Internal Only

- A list of changes that do not have user-facing impact, but represent
  significant improvements to the internals of Enso and related tools.

If there are no changes for a section, the section should contain a bullet point that reads "Nothing".

The changelog file is an ongoing record of changes, and may diverge between main and the various release branches.

Version Support

We aim to support a given major version for some period of time after the release of the next major version. For a detailed breakdown of the major versions that are currently supported, please see the security document.

Working on the Current Release

When working on the current release, development should take place against the main branch. When it is time to cut a release, the new commits on the main branch are cherry-picked onto the current release branch. From there, the release proceeds as described in release workflow above.

Backporting Fixes

Supporting a major version for some time after the release of the next major version will sometimes require backporting a fix to the previous major version from the current version or from main.

Backporting should only be used for applying fixes, not the addition of new features.

The process for performing such a backport is as follows:

1. Create a new branch called backport/version/fix-name, where version matches the version string of the corresponding release branch. This branch should branch off the corresponding release branch.
2. Back-port the fix to the newly created backport branch. This can be done by:
   • Cherry-picking the commit and performing fixups (preferred).
   • Re-implementing the fix manually (if cherry-picking will not work due to progression of the codebase).
3. Submit your backport/version/fix-name branch for review as a pull-request into the release/version branch.
4. Once the PR has passed CI and been approved by the appropriate reviewers, it can be merged into the release branch.