automerge.yml

name: Automerge

on:
  workflow_run:
    workflows:
    - Check
    types:
    - completed

jobs:

  test:
    name: Renovate
    if: github.event.workflow_run.conclusion == 'success'
    permissions:
      issues: write
      pull-requests: write
      contents: write
      actions: write
    runs-on: ubuntu-22.04
    steps:

    - name: Install uniget
      uses: uniget-org/uniget-action@v1
      with:
        prefix: helper
        tools: gojq

    - name: Test
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        REF: ${{ github.event.workflow_run.head_branch }}
      run: |
        set -o errexit -o pipefail
        
        echo "Running on branch: ${REF}"
        PR_JSON="$(
            curl --silent --show-error --fail --header "Authorization: token ${GITHUB_TOKEN}" \
                --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/pulls?state=open&head=uniget-org:${REF}" \
            | jq '.[]'
        )"
        PR="$( jq --raw-output '.number' <<<"${PR_JSON}" )"
        if test -z "${PR}"; then
            echo "ERROR: Failed to retrieve PR number from event payload"
            exit 1
        fi
        echo "PR ${PR} uses branch ${REF}"
        
        if ! jq --raw-output '.labels[].name' <<<"${PR_JSON}" | grep -q "^type/renovate$"; then
            echo "PR ${PR} does not have label type/renovate. Canceling"
            curl --silent --show-error --fail --header "Authorization: token ${GITHUB_TOKEN}" \
                --request POST \
                --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID}/cancel"
        fi

        RUN_URL="$(
            curl --silent --show-error --location --fail \
                --url "${GITHUB_API_URL}/repos/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID}" \
            | jq --raw-output '.html_url'
        )"
        echo "Extracted HTML URL for this run: ${RUN_URL}."

        curl --silent --show-error --fail \
                    --request POST \
                    --header "Authorization: Bearer ${GITHUB_TOKEN}" \
                    --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/${PR}/comments" \
                    --data '{"body": "Attempting automerge. See '"${RUN_URL}"'."}'

        MERGEABLE_STATE="$( jq --raw-output '.mergeable_state' <<<"${PR_JSON}" )"
        while test "${MERGEABLE_STATE}" == "unknown" || test "${MERGEABLE_STATE}" == "null"; do
            echo "Got mergeable state: ${MERGEABLE_STATE}"
            PR_JSON="$(
                curl --silent --show-error --fail \
                    --header "Authorization: token ${GITHUB_TOKEN}" \
                    --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/pulls/${PR}" \
                | jq --compact-output '.'
            )"
            MERGEABLE_STATE="$( jq --raw-output '.mergeable_state' <<<"${PR_JSON}" )"
        done
        case "${MERGEABLE_STATE}" in
            blocked)
                echo "PR ${PR} is blocked and can not be merged"
                curl --silent --show-error --fail \
                    --request POST \
                    --header "Authorization: Bearer ${GITHUB_TOKEN}" \
                    --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/${PR}/comments" \
                    --data '{"body": "PR is blocked and can not be merged. See '"${RUN_URL}"'."}'
                echo "Aborting workflow"
                exit 1
                ;;
            clean)
                echo "PR ${PR} is clean and can be merged"
                curl --silent --show-error --fail \
                    --request POST \
                    --header "Authorization: Bearer ${GITHUB_TOKEN}" \
                    --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/${PR}/comments" \
                    --data '{"body": "PR is clean and can be merged. See '"${RUN_URL}"'."}'
                ;;
            *)
                echo "ERROR: Unknown mergeable_state ${MERGEABLE_STATE} for PR ${PR}"
                curl --silent --show-error --fail \
                    --request POST \
                    --header "Authorization: Bearer ${GITHUB_TOKEN}" \
                    --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/${PR}/comments" \
                    --data '{"body": "PR has unknown mergeable_state ('"${MERGEABLE_STATE}"') and can not be merged. See '"${RUN_URL}"'."}'
                echo "Aborting workflow"
                exit 1
                ;;
        esac
        echo "PR ${PR} is ready for auto-merge"

        echo "Merging PR ${PR}..."
        http_code="405"
        merged=false
        max_attempts=3
        attempt=1
        while true; do
            echo "  Attempt ${attempt}"
            http_code="$(
                curl --silent --request PUT --header "Authorization: token ${GITHUB_TOKEN}" \
                    --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/pulls/${PR}/merge" \
                    --data '{"merge_method": "rebase"}' \
                    --output merge.json \
                    --write-out "${http_code}"
            )"
            if jq --exit-status 'select(.merged != null) | select(.merged == true)' merge.json >/dev/null; then
                echo "    Merged"
                merged=true
                break
            fi
            echo "    Got HTTP code ${http_code}"
            if test "${attempt}" -eq "${max_attempts}"; then
                echo "    Max attempt reached"
                break

            elif test "${http_code}" -eq 405; then
                echo "    Sleeping"
                cat merge.json
                sleep 5

            else
                echo "    Non-405 code"
                break
            fi
            attempt=$(( attempt + 1 ))
        done
        if ! ${merged}; then
            echo "ERROR: Unable to merge PR ${PR}"
            exit 1
        fi
        echo "PR ${PR} has been merged"

        echo "Deleting branch ${REF}..."
        if ! curl --silent --show-error --fail --request DELETE --header "Authorization: token ${GITHUB_TOKEN}" \
                --url "https://api.github.com/repos/${GITHUB_REPOSITORY}/git/refs/heads/${REF}"; then
            echo "ERROR: Unable to delete branch ${REF} from PR ${PR}"
            exit 1
        fi
        echo "Branch ${REF} has been deleted"