Awesome

action-semantic-pull-request

This is a GitHub Action that ensures that your pull request titles match the Conventional Commits spec. Typically, this is used in combination with a tool like semantic-release to automate releases.

Used by: Electron · Vite · Excalidraw · Apache · Vercel · Microsoft · Firebase · AWS – and many more.

Examples

Valid pull request titles:

fix: Correct typo
feat: Add support for Node.js 18
refactor!: Drop support for Node.js 12
feat(ui): Add Button component

Note that since pull request titles only have a single line, you have to use ! to indicate breaking changes.

See Conventional Commits for more examples.

Installation

If your goal is to create squashed commits that will be used for automated releases, you'll want to configure your GitHub repository to use the squash & merge strategy and tick the option "Default to PR title for squash merge commits".
Add the action with the following configuration:

name: "Lint PR"

on:
  pull_request_target:
    types:
      - opened
      - edited
      - synchronize
      - reopened

permissions:
  pull-requests: read

jobs:
  main:
    name: Validate PR title
    runs-on: ubuntu-latest
    steps:
      - uses: amannn/action-semantic-pull-request@v5
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

See the event triggers documentation below to learn more about what pull_request_target means.

Configuration

The action works without configuration, however you can provide options for customization.

The following terminology helps to understand the configuration options:

feat(ui): Add `Button` component
^    ^    ^
|    |    |__ Subject
|    |_______ Scope
|____________ Type

        with:
          # Configure which types are allowed (newline-delimited).
          # Default: https://github.com/commitizen/conventional-commit-types
          types: |
            fix
            feat
          # Configure which scopes are allowed (newline-delimited).
          # These are regex patterns auto-wrapped in `^ $`.
          scopes: |
            core
            ui
            JIRA-\d+
          # Configure that a scope must always be provided.
          requireScope: true
          # Configure which scopes are disallowed in PR titles (newline-delimited).
          # For instance by setting the value below, `chore(release): ...` (lowercase)
          # and `ci(e2e,release): ...` (unknown scope) will be rejected.
          # These are regex patterns auto-wrapped in `^ $`.
          disallowScopes: |
            release
            [A-Z]+
          # Configure additional validation for the subject based on a regex.
          # This example ensures the subject doesn't start with an uppercase character.
          subjectPattern: ^(?![A-Z]).+$
          # If `subjectPattern` is configured, you can use this property to override
          # the default error message that is shown when the pattern doesn't match.
          # The variables `subject` and `title` can be used within the message.
          subjectPatternError: |
            The subject "{subject}" found in the pull request title "{title}"
            didn't match the configured pattern. Please ensure that the subject
            doesn't start with an uppercase character.
          # The GitHub base URL will be automatically set to the correct value from the GitHub context variable.
          # If you want to override this, you can do so here (not recommended).
          githubBaseUrl: https://github.myorg.com/api/v3
          # If the PR contains one of these newline-delimited labels, the
          # validation is skipped. If you want to rerun the validation when
          # labels change, you might want to use the `labeled` and `unlabeled`
          # event triggers in your workflow.
          ignoreLabels: |
            bot
            ignore-semantic-pull-request
          # If you're using a format for the PR title that differs from the traditional Conventional
          # Commits spec, you can use these options to customize the parsing of the type, scope and
          # subject. The `headerPattern` should contain a regex where the capturing groups in parentheses
          # correspond to the parts listed in `headerPatternCorrespondence`.
          # See: https://github.com/conventional-changelog/conventional-changelog/tree/master/packages/conventional-commits-parser#headerpattern
          headerPattern: '^(\w*)(?:\(([\w$.\-*/ ]*)\))?: (.*)$'
          headerPatternCorrespondence: type, scope, subject

Work-in-progress pull requests

For work-in-progress PRs you can typically use draft pull requests from GitHub. However, private repositories on the free plan don't have this option and therefore this action allows you to opt-in to using the special "[WIP]" prefix to indicate this state.

Example:

[WIP] feat: Add support for Node.js 18

This will prevent the PR title from being validated, and pull request checks will remain pending.

Attention: If you want to use the this feature, you need to grant the pull-requests: write permission to the GitHub Action. This is because the action will update the status of the PR to remain in a pending state while [WIP] is present in the PR title.

name: "Lint PR"

permissions:
  pull-requests: write

jobs:
  main:
    name: Validate PR title
    runs-on: ubuntu-latest
    steps:
      - uses: amannn/action-semantic-pull-request@v5
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          wip: true

Legacy configuration for validating single commits

When using "Squash and merge" on a PR with only one commit, GitHub will suggest using that commit message instead of the PR title for the merge commit. As it's easy to commit this by mistake this action supports two configuration options to provide additional validation for this case.

          # If the PR only contains a single commit, the action will validate that
          # it matches the configured pattern.
          validateSingleCommit: true
          # Related to `validateSingleCommit` you can opt-in to validate that the PR
          # title matches a single commit to avoid confusion.
          validateSingleCommitMatchesPrTitle: true

However, GitHub has introduced an option to streamline this behaviour, so using that instead should be preferred.

Event triggers

There are two events that can be used as triggers for this action, each with different characteristics:

pull_request_target: This allows the action to be used in a fork-based workflow, where e.g. you want to accept pull requests in a public repository. In this case, the configuration from the main branch of your repository will be used for the check. This means that you need to have this configuration in the main branch for the action to run at all (e.g. it won't run within a PR that adds the action initially). Also if you change the configuration in a PR, the changes will not be reflected for the current PR – only subsequent ones after the changes are in the main branch.
pull_request: This configuration uses the latest configuration that is available in the current branch. It will only work if the branch is based in the repository itself. If this configuration is used and a pull request from a fork is opened, you'll encounter an error as the GitHub token environment parameter is not available. This option is viable if all contributors have write access to the repository.

Outputs

The outputs type, scope and subject are populated, except for if the wip option is used.
The error_message output will be populated in case the validation fails.

An output can be used in other steps, for example to comment the error message onto the pull request.

<details> <summary>Example</summary>

name: "Lint PR"

on:
  pull_request_target:
    types:
      - opened
      - edited
      - synchronize

permissions:
  pull-requests: write

jobs:
  main:
    name: Validate PR title
    runs-on: ubuntu-latest
    steps:
      - uses: amannn/action-semantic-pull-request@v5
        id: lint_pr_title
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - uses: marocchino/sticky-pull-request-comment@v2
        # When the previous steps fails, the workflow would stop. By adding this
        # condition you can continue the execution with the populated error message.
        if: always() && (steps.lint_pr_title.outputs.error_message != null)
        with:
          header: pr-title-lint-error
          message: |
            Hey there and thank you for opening this pull request! 👋🏼
            
            We require pull request titles to follow the [Conventional Commits specification](https://www.conventionalcommits.org/en/v1.0.0/) and it looks like your proposed title needs to be adjusted.

            Details:
            
            ```
            ${{ steps.lint_pr_title.outputs.error_message }}
            ```

      # Delete a previous comment when the issue has been resolved
      - if: ${{ steps.lint_pr_title.outputs.error_message == null }}
        uses: marocchino/sticky-pull-request-comment@v2
        with:   
          header: pr-title-lint-error
          delete: true

</details>