Release Flow

This package provides a library and command-line tool that generate a unique version number for a Git commit by analysing a Git repository. The repo is assumed to follow Release Flow conventions. The command outputs version variables based on information in the repository.

Installation

npm install @release-flow/release-flow

Note: if you're using this within an Azure DevOps pipeline, you might want to check out the custom extension, which is based on this library.

Command-line usage

Example:

npx rfver --pretty

You can see a full list of command-line options as follows:

npx rfver --help

Or check out the source code.

Output

The command outputs properties that provide a unique version for the current commit:

{
  "major": 2,
  "minor": 3,
  "patch": 1,
  "preReleaseLabel": "alpha",
  "sha": "67ebcd27627ed01760098f0f9779556b49ece66a",
  "buildType": "alpha",
  "branchName": "main",
  "commitDate": "2021-08-18T16:49:16.000Z",
  "commitsSinceVersionSource": 1,
  "versionSourceSha": "22443ada1ceee500b563645a2bf0bebf576028c9",
  "majorMinor": "0.0",
  "majorMinorPatch": "0.0.1",
  "shortSha": "67ebcd2",
  "semVer": "2.3.1-alpha.1"
}

Property values

| Property | Description | | --------------------- | ----------------------------------------------------------------------------- | | major | Major version number | | minor | Minor version number | | patch | Patch version number | | preReleaseLabel | Pre-release label (can be empty for release versions) | | semVer | A unique semantic version number | | sha | The Git SHA-1 hash of the commit | | shortSha | An abbreviated version of sha | | commitDate | The timestamp of the Git commit | | buildType | Denotes the type of branch the build (1) | | branchName | The abbreviated name of the branch | | versionSourceSha | The Git SHA-1 hash of the version source (2) | | commitsSinceVersionSource | The number of commits between the version source and the current commit | | majorMinor | Major and minor version, joined with . | | majorMinorPatch | Major, minor, and patch version, joined with . |

Notes

1. buildType

Possible values:

| Value | Meaning | | ----- | ------- | | alpha | Build is from a commit on the trunk branch | | beta | Build is from a commit on a release/* branch | | release | Build is from a release tag | | pull-request | Build is from a refs/pull/* branch | | working-branch | Build is from a commit on another branch, assumed to be a short-lived working branch |

2. Version Source

The version source indicates the commit that the calculated version number is based on. The version source can be:

• The initial commit in the repo.

• The commit from which the closest reachable release branch was forked (if on trunk branch).

• The closest commit on the current branch that was tagged with a release number (if on a release branch).

Configuration

A file (by default called rfconfig.yml) should be present in the repository root directory to configure the behavior of the task, in particular the selection of which versioning strategy variant (see below) to use.

A basic file looks like this:

strategy:
  kind: SemVer # or Milestone

A few more options exist, but they are for unusual use cases:

strategy:

  # The version numbering strategy - see below for details.
  # Allowed values: 'SemVer' or 'Milestone', default 'SemVer'
  kind: SemVer

  # The initial seed version number if no version sources (release branches or tags)
  # are present in the repository. If using Milestone strategy, the baseNumber should
  # simply be the major version e.g. 2. Defaults to 0.0, or 0, depending on the
  # numbering strategy.
  baseNumber: 2.1

# The prefix that identifies a release branch. Default = 'release/'
releaseBranchPrefix: 'myrelease/'

# Prefixes for working branches (not release or trunk). Defaults to
# ['feature/', 'bugfix/', '- hotfix/', 'merge/']
workingBranchPrefixes:
- feat-
- bug-

# Whether to remove the working branch prefix from the branch name when generating the preReleaseLabel.
# Default: true
stripBranchPrefixFromLabel: false

# Whether to fail with an error if the branch is not recognised as release or trunk, and its prefix doesn't match
# a working branch prefix. Default: true
failOnUnknownPrefix: false

# The name of the trunk or long-running branch in Release Flow. Defaults to
# 'master' for backward compatibility.
trunkBranchName: 'main'

Versioning variants

There are two supported variants of Release Flow:

• Semantic versioning

• Milestone versioning

Both variants output build numbers in a similar format, but there are subtle differences between them in terms of how the version number increments.

Semantic versioning

This variant assumes that you want to produce build version numbers that are compatible with Semantic Versioning, e.g. 1.2.3-beta.1. It's most suitable for creating builds of packages that other builds depend on, e.g. NuGet packages, where the semantic meaning of a breaking change is important.

In this variant, you create a release branch for each Minor version number, e.g. release/2.1. The Minor version of non-release branches increments automatically based on the latest reachable release branch. On the release branch, the Patch version increments by tagging.

If you want to increment the Major version, simply create a release branch with a changed Major version number e.g. release/3.0. It's up to you to ensure that you create appropriately-numbered release branches, so don't go backwards with your branch numbering.

Milestone versioning

This variant is most suitable for creating builds of code that doesn't have any other code dependent on it, e.g. web apps. In this variant, it's the Major version number that is incremented for each 'Milestone' (release branch), and the Patch version number is always 0.

In Milestone versioning, you create a release branch for each Milestone in the form release/M1 (the prefix is configurable).

Note that this variant still produces version numbers that are syntactically identical to semantic version numbers - the difference is that a change in Major version doesn't necessarily indicate a breaking change.

Branch naming

The task makes various assumptions about the branching structure based on Release Flow conventions - for a deeper understanding, consult the source code! - but basically it assumes that:

• A long-running branch exists. The branch name can be configured in rfconfig.yml - the default is master for backward compatibility. This long-lived branch is referred to as trunk within this documentation, although the modern standard name is main.

• Branches in the form release/* denote a release preparation branch. Commits to these branches produce beta prerelease builds. The exact form of the sub-branch is dependent on the type of versioning that is configured.

• Creating tags in the form vX.Y[.Z] triggers a full release build.

• Any other branches (e.g. bugfix/*, hotfix/*, and feature/*) are working branches that are branched from trunk and intended to be merged back to trunk. The changes might get cherry-picked onto a release/* branch.

Other release flows

The releaseflow.org website describes a different form of release flow, which is (as the site admits) just a 'trendy name for the Release Branching strategy'. This is unfortunate, as the form of Release Flow described on the Microsoft blog, and implemented here, is different in one crucial way: in true Release Flow, hotfixes to a release are first performed on the trunk branch then cherry-picked onto the release branch (with few exceptions). In the release branching strategy, they suggest to fix the release branch and then cherry-pick onto the trunk.

Apart from practical reasons why hotfixing the trunk is preferable (see the MS release flow document), this library doesn't currently support branching from a release branch. In true Release Flow, this hardly ever happens, so it's not a major limitation (though a fix is planned).