spiff-arena/.github/workflows/auto-merge-dependabot-prs.yml

# see also https://stackoverflow.com/a/68365564/6090676
name: Dependabot auto-merge
on:
  workflow_run:
    workflows: ["Tests"]
    # completed does not mean success of Tests workflow. see below checking github.event.workflow_run.conclusion
    types:
      - completed

# workflow_call is used to indicate that a workflow can be called by another workflow. When a workflow is triggered with the workflow_call event, the event payload in the called workflow is the same event payload from the calling workflow. For more information see, "Reusing workflows."

# https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request
# maybe hook into this instead of workflow_run:
# on:
#   pull_request:
#   pull_request_target:
#     types: [labeled]

permissions:
  # for gh pr review
  pull-requests: write
  # for gh pr merge
  contents: write

jobs:
  # uncomment this to print the context for debugging in case a job is getting skipped
  printJob:
    name: Print event
    runs-on: ubuntu-latest
    steps:
      - name: Dump GitHub context
        env:
          GITHUB_CONTEXT: ${{ toJson(github) }}
        run: |
          echo "$GITHUB_CONTEXT"

  dependabot:
    runs-on: ubuntu-latest
    if: ${{ github.actor == 'dependabot[bot]' && github.event.workflow_run.event == 'pull_request' && github.event.workflow_run.conclusion == 'success' }}
    steps:
      - name: Development Code
        uses: actions/checkout@v3

      ###### GET PR NUMBER
      # we saved the pr_number in tests.yml. fetch it so we can merge the correct PR.
      # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#workflow_run
      # https://github.com/actions/github-script
      - name: "Download artifact"
        uses: actions/github-script@v6
        with:
          script: |
            console.log("download artifact: started")
            console.log("download artifact: content.payload: ", context.payload)
            let allArtifacts = await github.rest.actions.listWorkflowRunArtifacts({
              owner: context.repo.owner,
              repo: context.repo.repo,
              run_id: context.payload.workflow_run.id,
            });
            console.log("download artifact: got allArtifacts")
            console.log("download artifact: allArtifacts: ", allArtifacts)
            let matchArtifact = allArtifacts.data.artifacts.filter((artifact) => {
              return artifact.name == "pr_number"
            })[0];
            console.log("download artifact: got matchArtifact: ", matchArtifact)
            let download = await github.rest.actions.downloadArtifact({
              owner: context.repo.owner,
              repo: context.repo.repo,
              artifact_id: matchArtifact.id,
              archive_format: 'zip',
            });
            let fs = require('fs');
            fs.writeFileSync(`${process.env.GITHUB_WORKSPACE}/pr_number.zip`, Buffer.from(download.data));
      - name: "Unzip artifact"
        run: unzip pr_number.zip
      ###########

      - name: print pr number
        run: cat pr_number
      # the repo requires one approval. if a dependabot change passes tests, that is good enough.
      - name: approve pr
        run: gh pr review --approve "$(cat pr_number)"
        env:
          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
      # if the merge --auto flag were added, and if the repo allowed it at https://github.com/sartography/spiff-arena/settings,
      # it would set up the pr to auto merge when all requirements were met. but we just want to merge now.
      - name: set up pr to auto merge when all requirements are met
        run: gh pr merge --squash "$(cat pr_number)"
        env:
          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}