Autorelease Tagger

Generates new version tags from git history

The process, in detail:

• Use git describe to figure out the nearest ancestor version tag (v*) of the current commit
• If that tag is pointing to this commit, do nothing
• Otherwise, figure out the next version by looking at the first line of all commits between the last version and the current commit:
  • figure out the bump strategy:
    • extract any instances of [(major|minor|patch)(-release)?] (i.e. [major], [minor], [patch], [major-release], etc)
    • use the highest one found
    • if no explicit bump is found, usedefaultBump (defaults to minor)
  • if the bump strategy is greater than minBump (default unset), use minBump instead (conversely used to ensure all new master commits create minor versions instead of patch releases)
  • apply the bump to make a new version:
    • if releaseTrigger is auto, a new release is always made
    • if releaseTrigger is commit, a new release is only made if the commit message contains [release] (or [major-release], [minor-release], [patch-release])
• export the new version as an environment variable (if a key is provided in exportEnv)
• tag it (if doTag, default true)
• push it (if doPush, default true except for Pull Requests)

versionTemplate:

As of 2020-12, a versionTemplate option is allowed, which provides a convenient way to specify numComponents, minBump, as well as validating that the chosen version matches the expected pattern.

Examples include:

v1.2.x: allow only patch increments v1.x.x: allow minor or patch increments v1.x.0: allow only minor increments vx.x.x: equivalent to numComponents: 3

The handling of versionTemplate is intentionally complex, to "do the right thing" for common use cases without requiring the use of unweildy workflow expressions:

• any leading refs/heads/ is stripped off
• if the value does not begin with a version component (optional leading v, then at least one digit, then .), it will be ignored
• if you supply both versionTemplate and numComponents, the max() of the two values is taken (so you can have a v2.x branch but still use 3 components)
• if you supply both versionTemplate and minBump, minBump is ignored (typically minBump is used only on the main branch, to use on a version branch you will need to name it e.g. v2.x.0)

This lets you pass in the branch name and have it work for both master and appropriately-named version branches, like so:

- uses: timbertson/autorelease-tagger-action@v1
  with:
    numComponents: 3
    minBump: minor
    versionTemplate: ${{ github.base_ref || github.ref }}

That will use the base_ref (destination branch) for a pull request, and the current branch for a push event. For the main branch it acts like a versionTemplate of vx.x.0 thanks to the default numComponents and minBump.

Big thanks

Inpired by the Github Tag Bump action, but with a few improvements:

• use git describe
• implement in JS (well, it's better than bash), with tests
• minBump
• not hardcoded to 3 release components
• stricter bump detection (matches whole words, not just substring)
• support for explicit version template
• still does validation and tagging on PR branches (doPush defaults to false for PRs)