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.

Once a release has been made it is immutable. The release should only ever be edited to mark it as broken. Nothing else should ever be changed.

No two release workflows can be running at once, to avoid race conditions since releases must update files in S3. Make sure that tags which trigger release builds are pushed sequentially, only pushing the next one after the previous build has finished.

• Versioning
  • Launcher Versioning
• Release Branches
• Release Workflow
  • Breaking Release Workflow
  • Tag Naming
  • Manifest Files
  • Breaking Changes to Launcher Upgrade
  • 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:

• major version a represents the year of the release, e.g. 2020.1.1 is the first release of 2020.
• Breaking changes to language behaviour or the public API will result in a minor 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 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 Workflow

Enso does not use release branches, but instead uses tags to mark releases. The same commit may be tagged multiple times, once for each release that it is a part of.

Cutting a release for Enso proceeds as follows:

1. Ensure that the release notes are up to date and that the top header refers to the version that is being released.

2. Invoke the "Promote Release" workflow, either by:

   • Triggering it using web interface;
   • Triggering it using GitHub CLI. The following command should be issued from the root of the repository:

     gh workflow run promote.yml -f designator=<designator>
     

     where <designator> is denotes what kind of release is being made. It can be one of:
     • stable - a stable release (bump to minor version);
     • patch - a patch release (stable release with a bump to patch version);
     • rc - a release candidate for the next stable release;
     • nightly - a nightly release.

   The promote workflow acts in the following steps:

   • generate a new version string for the release;
   • create a release draft on GitHub;
   • build and upload assets for the release on all platforms;
   • publish the release on GitHub.

   The final step also tags the released commit with the version string.

3. If the release was stable or patch, immediately update the changelog by adding a new header for the next release, and marking the released one with the version generated.

Tag Naming

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

Manifest Files

Manifest files are used to describe metadata about various releases for use by the Enso tooling.

Engine Manifest

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,
• minimum-project-manager-version - specifies the minimum version of the project manager that should be used with this release of Enso; currently it is the same as the launcher version but this may change in the future,
• 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.

The minimum launcher and project manager versions are kept as separate fields, because at some point the same runtime version management logic may be associated with different versions of these components.

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
minimum-project-manager-version: 0.0.1
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"
graal-vm-version: 20.2.0
graal-java-version: 11

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.

Launcher Manifest

Additionally, each release should contain an asset named launcher-manifest.yaml which contains launcher-specific release metadata.

It contains the following fields:

• minimum-version-for-upgrade - specifies the minimum version of the launcher that is allowed to upgrade to this launcher version. If a launcher is older than the version specified here it must perform the upgrade in steps, first upgrading to an older version newer than minimum-version-for-upgrade and only then, using that version, to the target version. This logic ensures that if a newer launcher version required custom upgrade logic not present in older versions, the upgrade can still be performed by first upgrading to a newer version that does not require the new logic but knows about it and continuing the upgrade with that knowledge.
• files-to-copy - a list of files that should be copied into the distribution's data root. This may include the README and similar files, so that after the upgrade these additional files are also up-to-date. These files are treated as non-essential, i.e. an error when copying them will not cancel the upgrade (but it should be reported).
• directories-to-copy - a list of directories that should be copied into the distribution's data root. Acts similarly to files-to-copy.

A template manifest file, located in distribution/launcher-manifest.yaml, is automatically copied to the release. If any new files or directories are added or a breaking change to the upgrade mechanism is being made, this manifest template must be updated accordingly.

Breaking Changes to Launcher Upgrade

If at any point the launcher's upgrade mechanism needs an update, i.e. additional logic must be added that was not present before, special action is required.

First, the additional logic has to be implemented and a new launcher version should be released which includes this additional logic, but does not require it yet. Then, another version can be released that can depend on this new logic and its minimum-version-for-upgrade has to be bumped to that previous version which already includes new logic but does not depend on it.

This way, old launcher versions can first upgrade to a version that contains the new logic (as it does not depend on it yet, the upgrade is possible) and using that new version, upgrade to the target version that depends on that logic.

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.

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.

When the release is marked as broken at GitHub, a GitHub Actions Workflow is triggered that also updates the release in the fallback mechanism. Given its current implementation is prone to race conditions when updating releases, the broken file should be added to releases one by one, making sure that only one update workflow is running at the same time and that no release workflows are running in parallel with it.

In an unusual situation in which you want to upload a release that is marked as broken from the start, you should first publish it in a non-broken state and only mark it as broken after publishing. That is because the GitHub Workflow that will persist the broken mark to S3 is not triggered for release drafts.

When marking the release as broken, you should make sure that the workflow persisting the broken mark to Se has succeeded and re-run it if necessary.

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.