name: tailcat

# This workflow tests the tailscale/tailcat repo against the tailscale.com
# module at head, rather than the version tailcat pins in its go.mod. It
# exists as an early warning that a change here breaks tailcat's API or
# behavior expectations. A failure might be fine if it's an intentional,
# coordinated change, but it's here to prevent accidental breakage.

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main
    paths:
      - "**/*.go"
      - "go.mod"
      - "go.sum"
      - ".github/workflows/tailcat.yml"

concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
  cancel-in-progress: true

jobs:
  tailcat:
    name: heads-up-hypothetical-tailcat-build-using-this-commit
    runs-on: ubuntu-latest
    steps:
      - name: Check out tailscale
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          path: tailscale

      - name: Check out tailcat
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          repository: tailscale/tailcat
          path: tailcat

      - name: Set up Go workspace
        working-directory: tailcat
        run: |
          ../tailscale/tool/go work init . ../tailscale
          ../tailscale/tool/go work sync

      - name: Run tailcat tests
        working-directory: tailcat
        run: ../tailscale/tool/go test ./...

      - name: Explain failure
        if: failure()
        run: |
          cat <<'EOF' | tee -a "$GITHUB_STEP_SUMMARY"
          Don't panic!

          This job builds the tailscale/tailcat repo against the tailscale.com
          module at this commit, not the version tailcat actually pins in its
          go.mod. A failure here does NOT break tailcat today; nothing breaks
          until tailcat bumps its tailscale.com dependency to include this
          change.

          This is only an early heads-up. Be concerned only if this API or
          behavior breakage is unexpected. If the breakage is intentional,
          proceed and coordinate a matching tailcat update.
          EOF