name: Detect invalid publish PRs

# Stage 1 of 2 (see close-invalid-publish-prs.yml for stage 2).
#
# Some contributors try to "publish" a server by opening a PR that adds files
# under servers/ or edits data/seed.json. That is not how publishing works -
# servers are published with the mcp-publisher CLI against the live registry
# API. This job only DETECTS such PRs. It runs from the (untrusted) PR context
# with a read-only token, so it cannot comment on or close anything. When it
# finds a match it records just the PR number as an artifact; the privileged
# stage-2 workflow picks that up via workflow_run and acts on it.
#
# We never check out or run the PR's code - we only read changed file paths.

on:
  pull_request:
    types: [opened, reopened]

permissions:
  contents: read
  pull-requests: read

jobs:
  detect:
    runs-on: ubuntu-latest
    env:
      GH_TOKEN: ${{ github.token }}
      GH_REPO: ${{ github.repository }}
      PR_NUMBER: ${{ github.event.pull_request.number }}
      AUTHOR_ASSOCIATION: ${{ github.event.pull_request.author_association }}
    steps:
      - name: Classify PR
        id: classify
        run: |
          set -euo pipefail
          match=false

          # Maintainers may legitimately touch these files (e.g. dev seed data),
          # so never flag their PRs.
          case "$AUTHOR_ASSOCIATION" in
            MEMBER|OWNER|COLLABORATOR)
              echo "Author association '$AUTHOR_ASSOCIATION' is trusted; not flagging."
              ;;
            *)
              # Use the paginated REST endpoint: `gh pr view --json files` caps
              # at 100 files with no pagination, which could truncate a large PR
              # and cause a false match.
              mapfile -t FILES < <(gh api --paginate "repos/$GH_REPO/pulls/$PR_NUMBER/files" --jq '.[].filename')
              if [ "${#FILES[@]}" -gt 0 ]; then
                # Flag only if the PR touches *exclusively* publish-attempt files
                # and nothing else, so that legit PRs touching seed data
                # alongside real code are left alone.
                #
                # Keep this list in sync with the copy in stage 2. It stays an
                # explicit list rather than a broad `**/server.json` glob:
                # because we require *every* file to match, an over-broad
                # pattern would auto-close a legitimate single-file PR.
                # data/servers/** is here because #1524 put its server.json
                # there - a natural guess next to data/seed.json - and slipped
                # through the original servers/**-only list.
                publish_attempt=0
                other=0
                for f in "${FILES[@]}"; do
                  if [[ "$f" == servers/* \
                     || "$f" == data/servers/* \
                     || "$f" == data/data/servers/* \
                     || "$f" =~ ^data/[^/]*server\.json$ \
                     || "$f" == "data/seed.json" \
                     || "$f" == "server.json" \
                     || "$f" == "servers.json" ]]; then
                    publish_attempt=1
                  else
                    echo "Non-publish file changed: $f"
                    other=1
                  fi
                done
                if [ "$publish_attempt" -eq 1 ] && [ "$other" -eq 0 ]; then
                  match=true
                fi
              fi
              ;;
          esac

          echo "PR #$PR_NUMBER match=$match"
          echo "match=$match" >> "$GITHUB_OUTPUT"
          if [ "$match" = "true" ]; then
            echo "$PR_NUMBER" > pr-number.txt
          fi

      - name: Record flagged PR number
        if: steps.classify.outputs.match == 'true'
        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v4
        with:
          name: flagged-pr
          path: pr-number.txt
          retention-days: 1