name: headless chrome
description: Install Chrome and prove it starts headless before a driver depends on it.

runs:
  using: composite
  steps:
    # stable is setup-chrome v2's own default, spelled out so a new release of
    # the action cannot move the browser these jobs drive. The alternative it
    # offers is Chrome for Testing latest, which tracks ahead of the channel
    # users run.
    - uses: browser-actions/setup-chrome@2e1d749697dd1612b833dba4a722266286fbefcd # v2.1.2
      with:
        chrome-version: stable

    # Ubuntu 24.04 (current ubuntu-latest) restricts unprivileged user
    # namespaces via AppArmor, which stops headless Chrome from starting even
    # with --no-sandbox: the process launches but never opens its DevTools
    # socket. Re-enable them so the driver's Chrome can come up.
    - name: Allow Chrome under unprivileged user namespaces
      shell: bash
      run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0

    # Fail here with Chrome's own stderr if the browser can't launch, instead
    # of letting the driver report an opaque DevTools timeout downstream.
    - name: Verify headless Chrome starts
      shell: bash
      run: |
        chrome --version
        chrome --headless --no-sandbox --disable-gpu --disable-dev-shm-usage \
          --dump-dom 'data:text/html,<title>ok</title>'