def _verify_app_source_dir(src_dir, mode, enforce=True):
    """Performs syntax and lint checks on the app source.

    Precondition: the dxapp.json file exists and can be parsed.
    """
    temp_dir = tempfile.mkdtemp(prefix='dx-build_tmp')
    try:
        _verify_app_source_dir_impl(src_dir, temp_dir, mode, enforce=enforce)
    finally:
        shutil.rmtree(temp_dir)