Path rootDirectory = findRoot(basedir);
        if (rootDirectory == null) {
            throw new IllegalStateException(getNoRootMessage());
        }
        return rootDirectory;
    }

    @Nullable
    default Path findRoot(Path basedir) {
        Path rootDirectory = basedir;
        while (rootDirectory != null && !isRootDirectory(rootDirectory)) {

            return this;
        }

        public Builder withRootDirectory(@Nullable Path rootDirectory) {
            this.rootDirectory = rootDirectory;
            return this;
        }

        public ProtoSession build() {
            return new Impl(userProperties, systemProperties, startTime, topDirectory, rootDirectory);
        }

        private static class Impl implements ProtoSession {

        configuration.addChild("uri", "${session.rootDirectory.uri}");
        configuration.addChild("path", "${session.rootDirectory}");
        configuration.addChild("uriString", "${session.rootDirectory.uri.string}");
        configuration.addChild("uriAsciiString", "${session.rootDirectory.uri.ASCIIString}");
        configuration.addChild("pathString", "${session.rootDirectory.string}");

        Mojo mojo = new Mojo();

        configuration.addChild("uri", "${session.rootDirectory.uri}");
        configuration.addChild("path", "${session.rootDirectory}");
        configuration.addChild("uriString", "${session.rootDirectory.uri.string}");
        configuration.addChild("uriAsciiString", "${session.rootDirectory.uri.ASCIIString}");
        configuration.addChild("pathString", "${session.rootDirectory.string}");

        Mojo mojo = new Mojo();

        this.userProperties = requireNonNull(userProperties);
        this.systemProperties = requireNonNull(systemProperties);
        this.topDirectory = requireNonNull(topDirectory);
        this.rootDirectory = rootDirectory;
        this.coreExtensions = coreExtensions;
        this.ciInfo = ciInfo;
        this.options = options;
    }

    @Override
    public ParserRequest parserRequest() {
        return parserRequest;

        public XmlReaderRequestBuilder path(Path path) {
            this.path = path;
            return this;
        }

        public XmlReaderRequestBuilder rootDirectory(Path rootDirectory) {
            this.rootDirectory = rootDirectory;
            return this;
        }

        public XmlReaderRequestBuilder url(URL url) {
            this.url = url;
            return this;
        }

            // project present, but we could not determine rootDirectory: extra work needed
            if (context.invokerRequest.rootDirectory().isEmpty()) {
                Path rootDirectory = CliUtils.findMandatoryRoot(context.invokerRequest.topDirectory());
                request.setMultiModuleProjectDirectory(rootDirectory.toFile());
                request.setRootDirectory(rootDirectory);
            }
        }

        Files.writeString(mavenUserProps, "${includes} = ?${session.rootDirectory}/.mvn/maven-user.properties\n");
        Path rootDirectory = fs.getPath("C:\\myRootDirectory");
        Path topDirectory = rootDirectory.resolve("myTopDirectory");
        Path mvn = rootDirectory.resolve(".mvn");
        Files.createDirectories(mvn);
        Files.writeString(

        user.put("session.topDirectory", invokerRequest.topDirectory().toString());
        if (invokerRequest.rootDirectory().isPresent()) {
            user.put(
                    "session.rootDirectory",
                    invokerRequest.rootDirectory().get().toString());
        }
        this.protoSession = ProtoSession.newBuilder()
                .withSystemProperties(invokerRequest.systemProperties())

    }

    @Test
    void specials() {
        InvokerRequest invokerRequest = subject.parseInvocation(ParserRequest.mvn(
                        Arrays.asList("-Dfoo=${session.rootDirectory}", "-X"), mock(MessageBuilderFactory.class))
                .cwd(Path.of(System.getProperty("userDir")))
                .userHome(Path.of(System.getProperty("userHome")))
                .build());