return root.toFile().getAbsolutePath();
                }
                return null;
            }
        });

        interpolator.addValueSource(new MapBasedValueSource(context.getProjectProperties()));
        interpolator.addValueSource(new MapBasedValueSource(context.getUserProperties()));
        interpolator.addValueSource(new MapBasedValueSource(context.getSystemProperties()));

        startParameter.getSystemPropertiesArgs().putAll(properties.getRequestedSystemProperties());

        projectPropertiesCommandLineConverter.convert(parsedCommandLine, startParameter.getProjectProperties());

        if (!parsedCommandLine.getExtraArguments().isEmpty()) {
            startParameter.setTaskNames(parsedCommandLine.getExtraArguments());
        }

        Map<String, String> gradlePropertiesAsSeenByToolchains = new HashMap<>();
        gradlePropertiesAsSeenByToolchains.putAll(properties.getProperties());
        gradlePropertiesAsSeenByToolchains.putAll(startParameter.getProjectProperties());
        toolchainConfigurationBuildOptionBackedConverter.convert(args, gradlePropertiesAsSeenByToolchains, daemonParameters.getToolchainConfiguration());

     */
    Path getProjectDirectory();

    /**
     * Gets current calculated project properties
     *
     * @return The project properties, never {@code null}.
     */
    Map<String, String> getProjectProperties();

        buildSrcStartParameter.setCurrentDir(buildSrcDir);
        buildSrcStartParameter.setProjectProperties(containingBuildParameters.getProjectProperties());
        buildSrcStartParameter.doNotSearchUpwards();
        buildSrcStartParameter.setInitScripts(containingBuildParameters.getInitScripts());
        return buildSrcStartParameter;
    }

        this.projectDirectory = projectDirectory;

        return this;
    }

    @Override
    public Map<String, String> getProjectProperties() {
        return projectProperties;
    }

    public DefaultProfileActivationContext setProjectProperties(Properties projectProperties) {
        return setProjectProperties(toMap(projectProperties));

            this.currentDir = FileUtils.canonicalize(currentDir);
        } else {
            this.currentDir = new BuildLayoutParameters().getCurrentDir();
        }
    }

    public Map<String, String> getProjectProperties() {
        return projectProperties;
    }

    public void setProjectProperties(Map<String, String> projectProperties) {
        this.projectProperties = projectProperties;
    }

 * link:{javadocPath}/org/gradle/StartParameter.html#getProjectProperties--[StartParameter.projectProperties] and link:{javadocPath}/org/gradle/StartParameter.html#getSystemPropertiesArgs--[StartParameter.systemPropertiesArgs] now return immutable maps.

[[changes_4.6]]