merge-me-action

This Action approves and attempts to merge Pull Requests when triggered.

By using branch protection rules, it can be specified what the requirements are for a PR to be merged (e.g. require branches to be up to date, require status checks to pass).

Usage

The Action supports three run triggers:

check_suite (works only on the default branch).
pull_request_target for all branches.
workflow_run for all branches.

When using the Merge Me! Action, ensure security of your workflows. GitHub Security Lab provides more detailed overview of these risks involved in using pull_request_target and workflow_run triggers, as well as recommendations on how to avoid these risks.

Recommended setup differs between public and private repositories, however the Action can be used in other combinations as well.

Public repositories

Using a workflow_run trigger allows to provide the Merge Me! Action with necessary credentials, while allowing the CI to keep using pull_request trigger, which is safer than pull_request_target.

Create a new .github/workflows/merge-me.yaml file:

name: Merge me!

on:
  workflow_run:
    types:
      - completed
    workflows:
      # List all required workflow names here.
      - 'Continuous Integration'

jobs:
  merge-me:
    name: Merge me!
    runs-on: ubuntu-latest
    steps:
      - # It is often a desired behavior to merge only when a workflow execution
        # succeeds. This can be changed as needed.
        if: ${{ github.event.workflow_run.conclusion == 'success' }}
        name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          # Depending on branch protection rules, a  manually populated
          # `GITHUB_TOKEN_WORKAROUND` secret with permissions to push to
          # a protected branch must be used. This secret can have an arbitrary
          # name, as an example, this repository uses `DOTTBOTT_TOKEN`.
          #
          # When using a custom token, it is recommended to leave the following
          # comment for other developers to be aware of the reasoning behind it:
          #
          # This must be used as GitHub Actions token does not support pushing
          # to protected branches.
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Triggering on check_suite is similar:

name: Merge me!

on:
  check_suite:
    types:
      - completed

jobs:
  merge-me:
    name: Merge me!
    runs-on: ubuntu-latest
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Private repositories

Private repositories are less prone attacks, as only a restricted set of accounts has access to them. At the same time, CIs in private repositories often require access to secrets for other purposes as well, such as installing private dependencies. For these reasons, it is recommended to use pull_request_target trigger, which allows to combine regular CI checks and the Merge Me! Action into one workflow:

name: Continuous Integration

on:
  # Trigger on Pull Requests against the master branch.
  pull_request_target:
    branches:
      - master
    types:
      - opened
      - synchronize
  # Trigger on Pull Requests to the master branch.
  push:
    branches:
      - master

jobs:
  # Add other CI jobs, such as testing and linting. The example test job
  # showcases checkout settings which support `pull_request_target` and `push`
  # triggers at the same time.
  test:
    name: Test
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2
        with:
          # This adds support for both `pull_request_target` and `push` events.
          ref: ${{ github.event.pull_request.head.sha || github.sha }}
      - name: Setup Node.js
        uses: actions/setup-node@v2
        with:
          node-version: 20
          registry-url: https://npm.pkg.github.com
      - # This allows private dependencies from GitHub Packages to be installed.
        # Depending on the setup, it might be required to use a personal access
        # token instead.
        env:
          NODE_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        name: Install dependencies
        run: npm ci --ignore-scripts --no-audit --no-progress
      - name: Test
        run: npm run test
  merge-me:
    name: Merge me!
    needs:
      # List all required job names here.
      - test
    runs-on: ubuntu-latest
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          # Depending on branch protection rules, a  manually populated
          # `GITHUB_TOKEN_WORKAROUND` secret with permissions to push to
          # a protected branch must be used. This secret can have an arbitrary
          # name, as an example, this repository uses `DOTTBOTT_TOKEN`.
          #
          # When using a custom token, it is recommended to leave the following
          # comment for other developers to be aware of the reasoning behind it:
          #
          # This must be used as GitHub Actions token does not support pushing
          # to protected branches.
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    timeout-minutes: 5

Configuration

Enable auto-merge for a different bot

You may have another bot that also creates PRs against your repository and you want to automatically merge those. By default, this GitHub Action assumes the bot is dependabot. You can override the bot name by changing the value of GITHUB_LOGIN parameter:

jobs:
  merge-me:
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          GITHUB_LOGIN: my-awesome-bot-r2d2
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

A common scenario is to use Dependabot Preview (consider updating instead):

jobs:
  merge-me:
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          GITHUB_LOGIN: dependabot-preview
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

GITHUB_LOGIN option supports micromatch.

Opting in for using GitHub preview APIs

You may opt-in for using GitHub preview APIs, which enables the action to respect strict branch protection rules configured for the repository (Require status checks to pass before merging and Require branches to be up to date before merging options).

jobs:
  merge-me:
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          ENABLE_GITHUB_API_PREVIEW: true

Use of configurable pull request merge method

By default, this GitHub Action assumes merge method is SQUASH. You can override the merge method by changing the value of MERGE_METHOD parameter (one of MERGE, SQUASH or REBASE):

jobs:
  merge-me:
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          MERGE_METHOD: MERGE

Presets

Presets enable additional functionality which can be used to better personalize default behavior of the Merge me! Action.

Available presets are:

DEPENDABOT_MINOR - Merge only minor and patch dependency updates for pull requests created by Dependabot if the dependency version follows Semantic Versioning v2.
DEPENDABOT_PATCH - Merge only patch dependency updates for pull requests created by Dependabot if the dependency version follows Semantic Versioning v2.

jobs:
  merge-me:
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PRESET: DEPENDABOT_PATCH

Number of retries

In case the merge action fails, by default it will automatically be retried up to three times using an exponential backoff strategy. This means, the first retry will happen 1 second after the first failure, while the second will happen 4 seconds after the previous, the third 9 seconds, and so on.

It's possible to configure the number of retries by providing a value for MAXIMUM_RETRIES (by default, the value is 3).

jobs:
  merge-me:
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          MAXIMUM_RETRIES: 2

Enable for manual changes

There are cases in which manual changes are needed, for instance, in order to make the CI pass or to solve some conflicts that Dependabot (or the bot you are using) cannot handle. By default, this GitHub action will skip this case where the author is not dependabot (or the bot you are using). This is often desirable as the author might prefer to get a code review before merging the changes. For this, it checks whether all commits were made by the original author and that the commit signature is valid.

It is possible to override this default behavior by setting the value of ENABLED_FOR_MANUAL_CHANGES to 'true'.

jobs:
  merge-me:
    steps:
      - name: Merge me!
        uses: ridedott/merge-me-action@v2
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          ENABLED_FOR_MANUAL_CHANGES: 'true'

Important: Please note the single quotes around true.

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See usage notes on how to consume this package in your project.

Prerequisites

Minimal requirements to set up the project:

Node.js v14, installation instructions can be found on the official website, a recommended installation option is to use Node Version Manager. It can be installed in a few commands.
A package manager npm. All instructions in the documentation will follow the npm syntax.
Optionally a Git client.

Installing

Start by cloning the repository:

git clone git@github.com:ridedott/merge-me-action.git

In case you don't have a git client, you can get the latest version directly by using this link and extracting the downloaded archive.

Go the the right directory and install dependencies:

cd merge-me-action
npm install

That's it! You can now go to the next step.

Testing

All tests are being executed using Jest. All tests files live side-to-side with a source code and have a common suffix: .spec.ts. Some helper methods are being stored in the test directory.

There are three helper scripts to run tests in the most common scenarios:

npm run test
npm run test:watch
npm run test:coverage

Formatting

This project uses Prettier to automate formatting. All supported files are being reformatted in a pre-commit hook. You can also use one of the two scripts to validate and optionally fix all of the files:

npm run format
npm run format:fix

Linting

This project uses ESLint to enable static analysis. TypeScript files are linted using a custom configuration. You can use one of the following scripts to validate and optionally fix all of the files:

npm run lint
npm run lint:fix

Publishing

Publishing is handled in an automated way and must not be performed manually.

Each commit to the master branch is automatically tagged using semantic-release.

ridedott / merge-me-action

readme