PluginDescriptor pluginDescriptor = null;
            if (plugin.isExtensions() && !artifacts.isEmpty()) {
                // ignore plugin descriptor parsing errors at this point
                // these errors will reported during calculation of project build execution plan
                try {
                    pluginDescriptor = extractPluginDescriptor(artifacts.get(0), plugin);

                            + " is missing.",
                    dependency.getLocation(""));
            return null;
        }

        String imported = groupId + ':' + artifactId + ':' + version;

        if (importIds.contains(imported)) {
            StringBuilder message =
                    new StringBuilder("The dependencies of type=pom and with scope=import form a cycle: ");

    builder.put(k1, v1);
    return builder.build();
  }

  /**
   * Returns an immutable multimap containing the given entries, in order. Repeated occurrences of
   * an entry (according to {@link Object#equals}) after the first are ignored.
   */
  public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1, K k2, V v2) {

   * order of the returned multiset matches that of the element set of {@code multiset1} followed by
   * the members of the element set of {@code multiset2} that are not contained in {@code
   * multiset1}, with repeated occurrences of the same element appearing consecutively.
   *
   * <p>Results are undefined if {@code multiset1} and {@code multiset2} are based on different

     *
     * <p>In the current implementation, all values associated with a given key are stored in the
     * {@code Builder} object, even though only one of them will be used in the built map. If there
     * can be many repeated keys, it may be more space-efficient to use a {@link
     * java.util.LinkedHashMap LinkedHashMap} and {@link ImmutableMap#copyOf(Map)} rather than
     * {@code ImmutableMap.Builder}.
     *
     * @since 31.1
     */

    void testMirrorStopOnFirstMatch() {
        // exact matches win first
        Mirror mirrorA2 = newMirror("a2", "a,b", "http://a2");
        Mirror mirrorA = newMirror("a", "a", "http://a");
        // make sure repeated entries are skipped
        Mirror mirrorA3 = newMirror("a", "a", "http://a3");

        Mirror mirrorB = newMirror("b", "b", "http://b");
        Mirror mirrorC = newMirror("c", "d,e", "http://de");

                            errOn30,
                            Version.V20,
                            prefix + prefix2 + "classifier",
                            key,
                            "must be empty, imported POM cannot have a classifier.",
                            dependency);
                }
            } else if ("system".equals(dependency.getScope())) {