action.yml

name: 'Fast Forward Merge'
description: 'Merge a pull request by fast forwarding the target branch.'
author: 'Sequoia PGP'
inputs:
  github_token:
    description: 'GITHUB_TOKEN'
    default: '${{ github.token }}'
  merge:
    description: >
      Whether to actually merge the pull request or only check whether
      fast forwarding is possible.

      If true, the action will fast forward the target branch, if
      possible.  If false, the action will only post a comment
      indicating whether it is possible to fast forward the target
      branch.
    default: false
  comment:
    description: >
      Whether to post a comment.

      If set to true or always, this posts a comment to the pull
      request indicating whether it is possible to fast-forward the
      target branch, and, if merge is true, whether fast forwarding
      succeeded.

      If set to on-error (the default), a comment is only posted if
      an error occurs.

      If false or never, no comment is posted.  The comment is
      still available via the comment output variable, and in the
      step's summary.
    default: on-error
  debug:
    description: >
      Enables debugging output.

      If set to 1 or true, increases the workflow's verbosity.  This
      may also execute some additional RPCs, and so should normally
      be disabled.
    default: 0
outputs:
  comment:
    description: >
      The comment.

      A comment explaining whether fast forwarding is possible, and,
      if `merge` is true, whether it was successful.

      The comment is a JSON document with a single field, `body`.
    value: ${{ steps.fast-forward.outputs.comment }}
runs:
  using: "composite"
  steps:
    - id: fast-forward
      run: |
        export GITHUB_TOKEN=${{ inputs.github_token }}
        export DEBUG=${{ inputs.debug }}
        export COMMENT=${{ inputs.comment }}

        # github.action_path is set to $REPO.
        if test "x${{ inputs.merge }}" = xtrue
        then
            ${{ github.action_path }}/src/fast-forward.sh --merge
        else
            ${{ github.action_path }}/src/fast-forward.sh
        fi
      shell: bash
branding:
  icon: 'arrow-up-right'
  color: 'green'