forward-merge.yml

name: 'forward-merge'
on:
  workflow_dispatch:
  push:
    branches:
      - support
      - master
      - prerelease/minor

jobs:
  get-branch-names:
    # Only run if:
    # - commit contains '[skip release]' (release commits or commits that skipped a release)
    # - branch is prerelease/minor
    #
    # We don't want to run a forward merge on support/master on commits that will trigger a release.
    # This would cause forward merge to run twice (once for normal commit, and one for the release)
    # commit. `prerelease/minor` branch does not create release commits, so those branches are safe
    # to forward-merge. A release commit looks like "chore: Release vx.x.x [skip release]" and all
    # commits that skip the release action also contain "[skip release]". We will run forward merge
    # on any commit that will not trigger another commit
    if:
      startsWith(github.ref_name, 'prerelease/') || contains(github.event.head_commit.message,
      '[skip release]')
    runs-on: ubuntu-latest
    outputs: # Output branch names for the make-pull-request job
      branch: ${{steps.extract-branch.outputs.branch}}
      next-branch: ${{steps.extract-next-branch.outputs.branch}}

    steps:
      ## `github.ref` is in the form of `refs/head/{name}`. This step extracts `{name}` and saves it
      ## as an output for later use
      - name: Extract branch name
        id: extract-branch
        run: |
          echo "branch=$(echo ${GITHUB_REF#refs/heads/})" >> "$GITHUB_OUTPUT"

      - name: Extract next branch name
        id: extract-next-branch
        uses: Workday/canvas-kit-actions/get-next-branch@v1
        with:
          branch: ${{github.ref_name}}

      - name: Current Branch
        run: |
          echo ${{steps.extract-branch.outputs.branch}}

      - name: Next Branch
        run: |
          echo ${{steps.extract-next-branch.outputs.branch}}

  test-ff-only:
    needs: ['get-branch-names']
    runs-on: ubuntu-latest

    steps:
      ## First, we'll checkout the repository. We don't persist credentials because we need a
      ## Personal Access Token to push on a branch that is protected. See
      ## https://github.com/cycjimmy/semantic-release-action#basic-usage
      - uses: actions/checkout@v3
        with:
          persist-credentials: false
          ref: ${{needs.get-branch-names.outputs.next-branch}} # checkout the next branch
          fetch-depth: 0 # Needed to do merges

      ## Attempt to do a fast-forward-only merge. If this succeeds, there is no divergence
      ## between the branches and we do not need to retest. The commit has already been
      ## verified. If this line fails, it will trigger `verify-merge`
      - name: Test ff-only merge
        run: git merge origin/${{ needs.get-branch-names.outputs.branch }} --ff-only

      ## If the previous step passed, push the verified commit directly to the next branch
      - name: Push changes
        uses: ad-m/github-push-action@master
        with:
          github_token: ${{ secrets.GH_RW_TOKEN }}
          branch: refs/heads/${{ needs.get-branch-names.outputs.next-branch }}

  ## If the previous step failed, it means the fast-forward attempt failed. There is a
  ## divergence and we will need to merge the branches and verify everything works.
  verify-merge:
    runs-on: ubuntu-latest
    if: failure()
    needs: ['get-branch-names', 'test-ff-only']

    steps:
      ## First, we'll checkout the repository. We don't persist credentials because we need a
      ## Personal Access Token to push on a branch that is protected. See
      ## https://github.com/cycjimmy/semantic-release-action#basic-usage
      - uses: actions/checkout@v3
        with:
          persist-credentials: false
          fetch-depth: 0 # Needed to do merges

      - uses: Workday/canvas-kit-actions/install@v1
        with:
          node_version: 16.x

      ## A `yarn bump` will create a commit and a tag. We need to set up the git user to do this.
      ## We'll make that user be the github-actions user.
      - name: Config git user
        run: |
          git config --global user.name "${{ github.actor }}"
          git config --global user.email "${{ github.actor }}@users.noreply.github.com"
          git config --global pull.rebase false

      ## Create a merge branch
      - name: Forward merge
        run: node utils/forward-merge.js

      - name: Git Log
        run: git log

      # Keep steps separate for Github Actions annotation matching: https://github.com/actions/setup-node/blob/83c9f7a7df54d6b57455f7c57ac414f2ae5fb8de/src/setup-node.ts#L26-L33
      - name: Lint
        run: yarn lint

      - name: Dependency Check
        run: yarn depcheck

      - name: Type Check
        run: yarn typecheck

      - name: Unit tests
        run: yarn test

      - name: Build Storybook
        run: yarn build-storybook --quiet

      - name: Cache Build
        id: build-cache
        uses: actions/cache/@v2
        with:
          path: docs
          key: ${{ runner.os }}-build-${{ github.sha }}

      # Not working for now...
      # - name: Visual Tests
      #   uses: chromaui/action@main
      #   with:
      #     token: ${{ secrets.GITHUB_TOKEN }}
      #     appCode: dlpro96xybh
      #     storybookBuildDir: docs
      #     exitOnceUploaded: false
      #     exitZeroOnChanges: false
      #     ignoreLastBuildOnBranch: ${{ needs.get-branch-names.outputs.next-branch }}
      #     debug: true

      - name: Start Server
        run: npx http-server docs -p 9001 & npx wait-on http://localhost:9001

      - name: Integration tests
        run: yarn cypress run --record --parallel --env skip_storybook_test=true # skip the Storybook test during forward merges
        env:
          # Github Actions doesn't support encryption on forks
          # If these keys become compromised, we will rotate and disable these features
          # on forked PRs until a suitable workaround is found
          CYPRESS_RECORD_KEY: 3a9347b6-36ab-4a36-823d-709f4078b148
          CYPRESS_CACHE_FOLDER: .cache/cypress

      ## Push both the commit and tag created by Lerna's version command using a PAT
      - name: Push changes
        uses: ad-m/github-push-action@master
        with:
          github_token: ${{ secrets.GH_RW_TOKEN }}
          branch: refs/heads/${{ needs.get-branch-names.outputs.next-branch }}

  ## If we get here, it means the branches are not fast-forward mergeable, OR the merge commit
  ## failed verification. We will need manual intervention, so we'll create a pull request to
  ## be verified by a person.
  make-pull-request:
    runs-on: ubuntu-latest
    # Run only if the verify-merge job failed. If the test-ff-only fails, but verify-merge passes, we should skip
    if: failure() && needs.verify-merge.result == 'failure'
    needs: ['get-branch-names', 'verify-merge']

    steps:
      ## If we've failed any previous step, we'll need to create a PR instead
      - uses: NicholasBoll/action-forward-merge-pr@main
        with:
          token: ${{secrets.GH_RW_TOKEN}} # use PAT to force GH Actions to run the PR verify. The regular token will not
          branches: support+master,master+prerelease/minor,prerelease/minor+prerelease/major
          prefix: 'chore: '
          body: |
            This pull request was automatically created by an automated [forward-merge job](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}). The automated job failed automated checks and must be resolved manually.
            Reasons for failure may include:
            - Merge conflicts that cannot be automatically resolved
            - A merge resulted in check failures
              - Lint or type errors
              - Test failures
              - Unexpected visual changes
            The pull request should inform you of merge conflicts before you start if any.
            1. Run the following commands in your terminal. If this succeeds, skip step 2. The last command will run a script that tries to merge and resolve conflicts automatically.
                ```
                git branch -D merge/${{needs.get-branch-names.outputs.branch}}-into-${{ needs.get-branch-names.outputs.next-branch }} || true
                git fetch upstream
                git checkout --track upstream/merge/${{needs.get-branch-names.outputs.branch}}-into-${{ needs.get-branch-names.outputs.next-branch }}
                git pull upstream merge/${{needs.get-branch-names.outputs.branch}}-into-${{ needs.get-branch-names.outputs.next-branch }} -f
                git pull upstream ${{needs.get-branch-names.outputs.branch}}
                node utils/forward-merge.js
                ```
            2. If the previous step succeeded, skip to step 4.
            3. Resolve conflicts manually. Then run the following.
                ```
                git add .
                git commit -m "chore: Merge ${{needs.get-branch-names.outputs.branch}} into ${{ needs.get-branch-names.outputs.next-branch }}"
                ```
            4. Push the merge commit back to the pull request
                ```
                git push upstream merge/${{needs.get-branch-names.outputs.branch}}-into-${{ needs.get-branch-names.outputs.next-branch }}
                ```
            If there were no merge conflicts, the forward-merge job failed because of a test failure. You can wait for the pull request to give errors, or you can check the logs for failures. You'll have to update code to fix errors.
            This pull request will be merged using the `merge` strategy instead of the `squash` strategy. This means any commit in the log will show in the branch's history. Any commit you make should amend the merge commit. Use the following command:
            ```
            git commit --amend --no-edit
            ```
            You must then force-push the branch and the CI will rerun verification.
            Use the `automerge` label like normal and the CI will pick the correct merge strategy.