merge-upstream.yml

name: Merge the upstream

on:
  workflow_dispatch:
  schedule:
    - cron: '0 8 * * 5'

jobs:
  create-pr:
    runs-on: ubuntu-latest

    steps:

    - uses: actions/checkout@v3
      with:
        fetch-depth: 0
        sparse-checkout: '.'
        ref: akirak

    - name: Switch to a work branch
      id: start
      run: |
        git switch -C upstream-recipes
        echo "rev=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"

    - name: Fetch the upstream
      id: upstream
      run: |
        git remote add upstream https://github.com/melpa/melpa.git
        git fetch upstream master
        echo "ref=upstream/master" >> "$GITHUB_OUTPUT"

    - uses: DeterminateSystems/nix-installer-action@v4
      with:
        diagnostic-endpoint: ''

    - name: Configure the Git identity
      run: |
        # Set some identity. Actually it will be overridden later by git-filter-repo,
        # so it can be anything
        git config --add user.name 'github-actions[bot]'
        git config --add user.email '6270544+github-actions[bot]@users.noreply.github.com'

    - name: Retrieve the merge base
      run: |
        rev=$(git merge-base ${{ steps.upstream.outputs.ref }} ${{ steps.start.outputs.rev }})
        git switch -C merge-base "$rev"
        git push --force origin HEAD

    - name: Filter commits
      run: |
        git switch -C upstream-recipes ${{ steps.upstream.outputs.ref }}
        nix run nixpkgs#git-filter-repo -- \
          --path recipes/ --refs "merge-base..HEAD" \
          --commit-callback '
            commit.committer_name = commit.author_name
            commit.committer_email = commit.author_email
            commit.committer_date = commit.author_date
          ' --force

    - name: Rebase
      run: |
        git rebase -s ort -X ours ${{ steps.start.outputs.rev }}

    # A workaround to prevent peter-evans/create-pull-request from resetting the
    # head here:
    # <https://github.com/peter-evans/create-pull-request/blob/d806186ee3288c60a352af9852b6b18afbbfd87e/src/create-or-update-branch.ts#L178>
    - name: Detach the head
      run: git switch --detach `git rev-parse HEAD`

    - name: Create a pull request
      uses: peter-evans/create-pull-request@v5
      with:
        base: akirak
        branch: create-pull-request/recipes
        token: ${{ secrets.PAT_FOR_PR }}
        title: 'Merge the upstream recipe commits'
        labels: automation