def do_setup():
    """Do main VCS-independent setup function for installing Versioneer."""
    root = get_root()
    try:
        cfg = get_config_from_root(root)
    except (EnvironmentError, configparser.NoSectionError,
            configparser.NoOptionError) as e:
        if isinstance(e, (EnvironmentError, configparser.NoSectionError)):
            print("Adding sample versioneer config to setup.cfg",
                  file=sys.stderr)
            with open(os.path.join(root, "setup.cfg"), "a") as f:
                f.write(SAMPLE_CONFIG)
        print(CONFIG_ERROR, file=sys.stderr)
        return 1

    print(" creating %s" % cfg.versionfile_source)
    with open(cfg.versionfile_source, "w") as f:
        LONG = LONG_VERSION_PY[cfg.VCS]
        f.write(LONG % {"DOLLAR": "$",
                        "STYLE": cfg.style,
                        "TAG_PREFIX": cfg.tag_prefix,
                        "PARENTDIR_PREFIX": cfg.parentdir_prefix,
                        "VERSIONFILE_SOURCE": cfg.versionfile_source,
                        })

    ipy = os.path.join(os.path.dirname(cfg.versionfile_source),
                       "__init__.py")
    if os.path.exists(ipy):
        try:
            with open(ipy, "r") as f:
                old = f.read()
        except EnvironmentError:
            old = ""
        module = os.path.splitext(os.path.basename(cfg.versionfile_source))[0]
        snippet = INIT_PY_SNIPPET.format(module)
        if OLD_SNIPPET in old:
            print(" replacing boilerplate in %s" % ipy)
            with open(ipy, "w") as f:
                f.write(old.replace(OLD_SNIPPET, snippet))
        elif snippet not in old:
            print(" appending to %s" % ipy)
            with open(ipy, "a") as f:
                f.write(snippet)
        else:
            print(" %s unmodified" % ipy)
    else:
        print(" %s doesn't exist, ok" % ipy)
        ipy = None

    # Make sure both the top-level "versioneer.py" and versionfile_source
    # (PKG/_version.py, used by runtime code) are in MANIFEST.in, so
    # they'll be copied into source distributions. Pip won't be able to
    # install the package without this.
    manifest_in = os.path.join(root, "MANIFEST.in")
    simple_includes = set()
    try:
        with open(manifest_in, "r") as f:
            for line in f:
                if line.startswith("include "):
                    for include in line.split()[1:]:
                        simple_includes.add(include)
    except EnvironmentError:
        pass
    # That doesn't cover everything MANIFEST.in can do
    # (https://docs.python.org/2/distutils/sourcedist.html#commands), so
    # it might give some false negatives. Appending redundant 'include'
    # lines is safe, though.
    if "versioneer.py" not in simple_includes:
        print(" appending 'versioneer.py' to MANIFEST.in")
        with open(manifest_in, "a") as f:
            f.write("include versioneer.py\n")
    else:
        print(" 'versioneer.py' already in MANIFEST.in")
    if cfg.versionfile_source not in simple_includes:
        print(" appending versionfile_source ('%s') to MANIFEST.in" %
              cfg.versionfile_source)
        with open(manifest_in, "a") as f:
            f.write("include %s\n" % cfg.versionfile_source)
    else:
        print(" versionfile_source already in MANIFEST.in")

    # Make VCS-specific changes. For git, this means creating/changing
    # .gitattributes to mark _version.py for export-subst keyword
    # substitution.
    do_vcs_install(manifest_in, cfg.versionfile_source, ipy)
    return 0
Do main VCS-independent setup function for installing Versioneer.
versioneer.py