* (if applicable). This process will essentially remove duplicate repositories by merging them into one equivalent
     * repository. It is worth to point out that merging does not simply choose one of the input repositories and
     * discards the others but actually combines their possibly different policies.
     *

  </description>

  <build>
    <plugins>
      <!-- NOTE: It's essential part of this test variant to redefine the test plugin again, i.e. trigger plugin merging -->
      <plugin>
        <groupId>org.apache.maven.its.plugins</groupId>
        <artifactId>maven-it-plugin-log-file</artifactId>
        <version>2.1-SNAPSHOT</version>
      </plugin>
    </plugins>
  </build>

        // snapshot timestamp, or some other timestamp later encoded into the metadata.
        // TODO this needs to be repeated here so the merging doesn't interfere with the written metadata
        //  - we'd be much better having a pristine input, and an ongoing metadata for merging instead

        Map<ArtifactRepository, Metadata> previousMetadata = new HashMap<>();
        ArtifactRepository selected = null;

    <artifactId>parent</artifactId>
    <version>0.1</version>
  </parent>

  <artifactId>child</artifactId>

  <name>Maven Integration Test :: MNG-3979</name>
  <description>
    Test that during inheritance the merging/joining of subtrees with equal identifier doesn't crash if the parent
    POM has a non-empty element and the child POM has an empty element to join.
  </description>

  <properties/>

  <repositories>

    <artifactId>parent-2</artifactId>
    <version>0.1</version>
  </parent>

  <artifactId>child-2</artifactId>

  <name>Maven Integration Test :: MNG-3937</name>
  <description>
    Test that during inheritance/merging of a plugin execution the goals specified by child and parent are properly
    ordered.
  </description>

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

        return null;
    }

    public void setRepository(ArtifactRepository remoteRepository) {
        /*
         * NOTE: Metadata at the g:a level contains a collection of available versions. After merging, we can't tell
         * which repository provides which version so the metadata manager must not restrict the artifact resolution to
         * the repository with the most recent updates.
         */
    }

                for (Plugin element : src) {
                    if (element.isInherited() || !element.getExecutions().isEmpty()) {
                        // NOTE: Enforce recursive merge to trigger merging/inheritance logic for executions
                        Plugin plugin = Plugin.newInstance(false);
                        plugin = mergePlugin(plugin, element, sourceDominant, context);

  .
  .
  .
</plugins>

We need this form so that the model builder can make the first pass at merging. Full merging cannot be done because we don't know what the version of the plugin is yet that the user has requested. For plugins in the default lifecycle they are typically defined in the plugin management section of the parent POM. When the merging is complete we are going to have something that looks like the following:

<plugins>
  <plugin>

    <artifactId>parent-1</artifactId>
    <version>0.1</version>
  </parent>

  <artifactId>child-1</artifactId>

  <name>Maven Integration Test :: MNG-3937</name>
  <description>
    Test that during inheritance/merging of a plugin execution the goals specified by child and parent are properly
    ordered.
  </description>

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

  <artifactId>parent-2</artifactId>
  <version>0.1</version>
  <packaging>pom</packaging>

  <name>Maven Integration Test :: MNG-3937</name>
  <description>
    Test that during inheritance/merging of a plugin execution the goals specified by child and parent are properly
    ordered.
  </description>

  <build>
    <!-- This project uses plugin management for the test plugin -->
    <pluginManagement>