}

    private static List<String> visitAll(
            Collection<Vertex> children, Map<Vertex, DfsState> stateMap, List<String> list) {
        for (Vertex v : children) {
            DfsState state = stateMap.putIfAbsent(v, DfsState.VISITING);
            if (state == null) {
                visitAll(v.children, stateMap, list);
                stateMap.put(v, DfsState.VISITED);
                list.add(v.label);

        this.reference = (reference != null) ? reference : "";
        this.children = (children != null) ? Collections.unmodifiableList(children) : Collections.emptyList();
    }

    public Throwable getException() {
        return exception;
    }

    public String getMessage() {
        return message;
    }

    public String getReference() {
        return reference;
    }

  <artifactId>parent</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>pom</packaging>

  <name>Maven Integration Test :: MNG-3836</name>
  <description>
    Verify that children can *override* inherited plugin configuration.
  </description>

  <build>
    <pluginManagement>
      <plugins>
        <plugin>
          <groupId>org.apache.maven.its.plugins</groupId>

  </parent>

  <groupId>org.apache.maven.its.mng3836</groupId>
  <artifactId>child</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>Maven Integration Test :: MNG-3836</name>
  <description>
    Verify that children can *override* inherited plugin configuration.
  </description>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.its.plugins</groupId>

  <version>1.0</version>
  <packaging>pom</packaging>

  <name>Maven Integration Test :: MNG-2591</name>
  <description>
    Test aggregation of list configuration items for build plugins when using
    'combine.children=append' attribute.
  </description>

  <modules>
    <module>subproject</module>
  </modules>

  <build>
    <pluginManagement>
      <plugins>
        <plugin>

    }

    static boolean hasEdge(Graph graph, String v1, String v2) {
        Vertex vx1 = graph.getVertex(v1);
        Vertex vx2 = graph.getVertex(v2);
        return vx1 != null && vx2 != null && vx1.children.contains(vx2);
    }

                            parameterConfiguration.getInputLocation());

                    children.add(parameterConfiguration);
                }
            }
        }
        XmlNode finalConfiguration = new XmlNodeImpl("configuration", null, null, children, null);

        mojoExecution.setConfiguration(finalConfiguration);
    }

            throws ProjectBuildingException;

    /**
     * Builds the projects for the specified POM files and optionally their children.
     *
     * @param pomFiles The POM files to build, must not be {@code null}.
     * @param recursive {@code true} to recursively build submodules referenced by the POM files, {@code false} to

          <stringParams combine.children="append">
            <!-- NOTE: These values are deliberately not in alpha order! -->
            <stringParam>CHILD-1</stringParam>
            <stringParam>CHILD-3</stringParam>
            <stringParam>CHILD-2</stringParam>
            <stringParam>CHILD-4</stringParam>
          </stringParams>
          <listParam combine.children="append">

          <artifactId>maven-release-plugin</artifactId>
          <version>2.0-beta-4</version>
          <configuration>
            <!-- This element will be overridden by children -->
            <tagBase>https://svn.apache.org/repos/asf/maven/pom/tags</tagBase>
            <useReleaseProfile>false</useReleaseProfile>
            <goals>deploy</goals>
            <arguments>-Prelease</arguments>