A minimal GitHub action that uses the GitHub API to bump a Homebrew formula after a new release in your repository.

Usage example:

on:
  push:
    tags: 'v*'

jobs:
  homebrew:
    name: Bump Homebrew formula
    runs-on: ubuntu-latest
    steps:
      - uses: mislav/bump-homebrew-formula-action@v3
        with:
          # By default, this will edit the `my_formula.rb` formula in
          # homebrew-core to update its "url" field to:
          # `https://github.com/OWNER/REPO/archive/refs/tags/<tag-name>.tar.gz`
          # The "sha256" formula field will get automatically recomputed.
          formula-name: my_formula
        env:
          # the personal access token should have "repo" & "workflow" scopes
          COMMITTER_TOKEN: ${{ secrets.COMMITTER_TOKEN }}

The COMMITTER_TOKEN secret is required because this action will want to write to an external repository. You can generate a new Personal Access Token (classic) here and give it repo and workflow scopes.

How it works

Given a Homebrew formula Formula/my_formula.rb in the homebrew-core repo:

class MyFormula < Formula
  url "https://github.com/me/myproject/archive/refs/tags/v1.2.3.tar.gz"
  sha256 "<OLDSHA>"
  # ...
end

After we push a v2.0.0 git tag to a project that has this action configured, the formula will be updated to:

class MyFormula < Formula
  url "https://github.com/me/myproject/archive/refs/tags/v2.0.0.tar.gz"
  sha256 "<NEWSHA>"
  # ...
end

This action can update the following Homebrew formula fields:

• version
• url
• sha256 - for non-git download-url action input
• tag - for git-based download-url
• revision - for git-based download-url

Action inputs

Formula parameters:

• formula-name: the name of the Homebrew formula to bump. Defaults to lower-cased repository name.

• formula-path: the relative path of the Homebrew formula file to edit within the homebrew-tap repository. Defaults to Formula/<letter>/<formula-name>.rb for homebrew-core formulae and Formula/<formula-name>.rb otherwise.

• tag-name: the git tag name to bump the formula to. Defaults to the currently pushed tag.

• download-url: the package download URL for the Homebrew formula.

  Defaults to https://github.com/OWNER/REPO/archive/refs/tags/<tag-name>.tar.gz, where OWNER/REPO is the repository that is running the Actions workflow.

• download-sha256: the SHA256 checksum of the archive at download-url. Defaults to calculating the checksum by fetching the archive at run time.

Repository parameters:

• homebrew-tap: the full GitHub repository name (in the NAME/OWNER format) where the Homebrew formula should be updated. Defaults to Homebrew/homebrew-core.

• push-to: a specific fork of homebrew-tap where the edit should be pushed to. Defaults to creating or reusing a personal fork of the owner of COMMITTER_TOKEN. (Note: avoid using an organization-owned fork, as that breaks automation for homebrew-core).

• base-branch: the branch name in the homebrew-tap repository where the formula should be updated. Defaults to the main branch of the repository.

• create-pullrequest: a boolean value to either force or prohibit submitting a pull request to homebrew-tap. Defaults to false if COMMITTER_TOKEN has the privileges to directly push to base-branch in homebrew-tap.

• commit-message: the git commit message template to use when updating the formula. The following placeholders be expanded:

  Placeholder	Description
  {{formulaName}}	the name of the formula supplied in formula-name
  {{version}}	the version number for this release

  It's recommended that commit-message has both subject and body, i.e. that it contains a subject line followed by a blank line followed by body text. Otherwise, pull requests to Homebrew/homebrew-core might get denied by their automation.

  Defaults to:

  {{formulaName}} {{version}}
  
  Created by https://github.com/mislav/bump-homebrew-formula-action
  

Environment variables

• COMMITTER_TOKEN (required): needs write access to the repository specified by the homebrew-tap input, or enough privileges to fork the tap repo (usually homebrew-core) and submit a PR to it.

  Recommended "classic" token scopes: repo & workflow.

• GITHUB_TOKEN (optional): needs read access to the contents of the repository that is executing this action; will be used for verifying the SHA256 checksum of the downloadable archive for this release. Useful only if the repository that runs this Action is private and if COMMITTER_TOKEN has the public_repo scope only.

Examples

Comprehensive usage example:

on:
  push:
    tags: 'v*'
  # Alternatively, trigger this workflow after a stable release has been published:
  #release:
  #  types: [ released ]

jobs:
  homebrew:
    name: Bump Homebrew formula
    # Skip this job in case of git pushes to prerelease tags
    if: ${{ github.event_name != 'push' || !contains(github.ref, '-') }}
    runs-on: ubuntu-latest
    permissions:
      contents: read
    steps:
      - name: Extract version
        id: extract-version
        # Strip a string prefix from the git tag name:
        run: |
          echo "tag-name=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT

      - uses: mislav/bump-homebrew-formula-action@v3
        with:
          formula-name: my_formula
          formula-path: Formula/m/my_formula.rb
          homebrew-tap: Homebrew/homebrew-core
          base-branch: master
          download-url: https://example.com/packages/myformula-${{ steps.extract-version.outputs.tag-name }}.tar.gz
          commit-message: |
            {{formulaName}} {{version}}

            Created by https://github.com/mislav/bump-homebrew-formula-action
        env:
          COMMITTER_TOKEN: ${{ secrets.COMMITTER_TOKEN }}
          # GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Manual trigger

How to set up this action to be manually triggered instead of being triggered by pushing to a git tag:

on:
  workflow_dispatch:
    inputs:
      tag-name:
        description: 'The git tag name to bump the formula to'
        required: true

jobs:
  homebrew:
    name: Bump Homebrew formula
    runs-on: ubuntu-latest
    steps:
      - uses: mislav/bump-homebrew-formula-action@v3
        with:
          formula-name: my_formula
          tag-name: ${{ github.event.inputs.tag-name }}
          download-url: https://example.com/foo/myproject-${{ github.event.inputs.tag-name }}.tar.gz
        env:
          COMMITTER_TOKEN: ${{ secrets.COMMITTER_TOKEN }}

You could then use GitHub CLI to trigger that workflow:

gh workflow -R <OWNER>/<REPO> run release.yml --ref <BRANCH> -f "tag-name=v1.2.3"

Known limitations

This action is designed to be minimal, fast, and to run with very few requirements. For example, this action does not require a working Homebrew installation, nor cloning the Homebrew tap repository (since cloning the massive Homebrew/homebrew-core repository with git can take a long time). The only thing it does is using the GitHub API to make file edits to a Homebrew formula and to submit those edits as a PR.

Because of said design, this action is less featured than the official brew bump-formula-pr command that ships with Homebrew. Known limitations are:

• Limited support for bumping Homebrew casks

• Cannot bump formulae that need their versions to be synced with other formulae

• Cannot bump formulae which use Ruby if...else conditions to determine alternate download locations at runtime

• Cannot bump Python-based formulae which declare their PyPI dependencies as additional resource blocks