name: "Detect schema changes"

on:
  # IMPORTANT! This workflow is triggered by the `pull_request_target` event
  # which means that forked PRs will run with access secrets from the repo
  # it's forked from (the "target" repo).
  #
  # For this reason we only NEVER checkout the code from the pull request
  # (e.g. "ref: ${{ github.event.pull_request.head.sha }}") to prevent
  # accidentally running potentially untrusted code.
  #
  # By default the checkout will be:
  #   - GITHUB_SHA: Last commit on the PR base branch
  #   - GITHUB_REF: PR base branch
  #
  # ...unlike a typical PR where:
  #   - GITHUB_SHA: Last merge commit on the GITHUB_REF branch
  #   - GITHUB_REF: PR merge branch refs/pull/:prNumber/merge
  pull_request_target:

env:
  # note: this is used within hashFiles() so must be within the GITHUB_WORKSPACE path (or will silently fail)
  CI_COMMENT_FILE: .tmp/labeler-comment.txt
  # needs to be any string to uniquely identify the comment on a PR across multiple runs
  COMMENT_HEADER: "label-commentary"

jobs:
  label:
    name: "Label changes"
    runs-on: ubuntu-22.04
    permissions:
      contents: read
      pull-requests: write
      issues: write
    steps:

      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 #v4.2.2
        with:
          persist-credentials: false

      - run: python .github/scripts/labeler.py
        env:
          # note: this token has write access to the repo
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          GITHUB_PR_NUMBER: ${{ github.event.number }}

      - name: Delete existing comment
        if: ${{ hashFiles( env.CI_COMMENT_FILE ) == '' }}
        uses: marocchino/sticky-pull-request-comment@d2ad0de260ae8b0235ce059e63f2949ba9e05943 #v2.9.3
        with:
          header: ${{ env.COMMENT_HEADER }}
          hide: true
          hide_classify: "OUTDATED"

      - name: Add comment
        if: ${{ hashFiles( env.CI_COMMENT_FILE ) != '' }}
        uses: marocchino/sticky-pull-request-comment@d2ad0de260ae8b0235ce059e63f2949ba9e05943 #v2.9.3
        with:
          header: ${{ env.COMMENT_HEADER }}
          path: ${{ env.CI_COMMENT_FILE }}