name: Commit checker

on:

  pull_request:

jobs:

  commit-checker:

    name: Commit checker

    runs-on: ubuntu-latest

    steps:

    - name: Checkout

      uses: actions/checkout@v2

      with:

        fetch-depth: 4

    - name: Get pull-request commits

      run: |

        set -x

        # actions/checkout did a merge checkout of the pull-request. As such, the first

        # commit is the merge commit. This means that on HEAD^ is the base branch, and

        # on HEAD^2 are the commits from the pull-request. We now check if those trees

        # have a common parent. If not, we fetch a few more commits till we do. In result,

        # the log between HEAD^ and HEAD^2 will be the commits in the pull-request.

        DEPTH=4

        while [ -z "$(git merge-base HEAD^ HEAD^2)" ]; do

            git -c protocol.version=2 fetch --no-tags --prune --progress --no-recurse-submodules --deepen=${DEPTH} origin HEAD

            DEPTH=$(( ${DEPTH} * 4 ))

        done

        # Just to show which commits we are going to evaluate.

        git log --oneline HEAD^..HEAD^2

    - name: Checkout commit-checker

      uses: actions/checkout@v2

      with:

        repository: OpenTTD/OpenTTD-git-hooks

        path: git-hooks

        ref: master

    - name: Check commits

      run: |

        set -x

        HOOKS_DIR=./git-hooks/hooks GIT_DIR=.git ./git-hooks/hooks/check-commits.sh HEAD^..HEAD^2

        echo "Commit checks passed"