for (Plugin plugin : plugins) {
                Object key = plugin.getKey();
                Plugin first = normalized.get(key);
                if (first != null) {
                    plugin = merger.mergePlugin(plugin, first);
                }
                normalized.put(key, plugin);
            }

            if (plugins.size() != normalized.size()) {

          <dependencies>
            <dependency>
              <groupId>group</groupId>
              <artifactId>first</artifactId>
              <version>1</version>
            </dependency>
          </dependencies>
          <executions>
            <execution>
              <id>first</id>
              <goals>
                <goal>compile</goal>
              </goals>
            </execution>

+ Make sure you have a [GitHub account](https://github.com/signup/free).
+ If you're planning to implement a new feature, it makes sense to discuss your changes
  on the [dev list](https://maven.apache.org/mailing-lists.html) first.
  This way you can make sure you're not wasting your time on something that isn't
  considered to be in Apache Maven's scope.
+ Submit a ticket for your issue, assuming one does not already exist.

     * between any two nodes, if multiple exists. Uses scope relationships, defined
     * in <code>ArtifactScopeEnum</code>
     *
     * @param graph the "dirty" graph to be simplified via conflict resolution
     * @param scope scope for which the graph should be resolved
     *
     * @return resulting "clean" graph for the specified scope
     *
     * @since 3.0
     */

  <name>Maven Integration Test :: MNG-4008</name>
  <description>
    Verify that filter definitions are properly merged.
  </description>

  <build>
    <filters>
      <!-- NOTE: The first filter is deliberately defined by the child as well, so should not be added twice -->
      <filter>src/main/filters/child-a.properties</filter>
      <filter>src/main/filters/parent-c.properties</filter>

        for (Lifecycle lifecycle : getLifeCycles()) {
            logger.debug("Lifecycle {}", lifecycle);

            for (String phase : lifecycle.getPhases()) {
                // The first definition wins.
                if (!phaseToLifecycleMap.containsKey(phase)) {
                    phaseToLifecycleMap.put(phase, lifecycle);
                } else if (logger.isWarnEnabled()) {

    static {
        // Those two public constants are initialized here, as they need all the private constants
        // above to be initialized first, but the code style imposes the public constants to be
        // defined above the private ones...
        OS_FAMILY = getOsFamily();
        IS_WINDOWS = isFamily(FAMILY_WINDOWS);
    }

    private Os() {}

        /*
         * NOTE: "invoker:install" vs "appassembler:assemble": Both mojos use the artifact installer to put an artifact
         * into a repository. In the first case, the result needs to be a proper local repository that one can use for
         * local artifact resolution. In the second case, the result needs to precisely obey the path information of the

        // POMs are always returned from the file system
        if ("pom".equals(artifact.getExtension())) {
            return project.getFile();
        }

        // First check in the project local repository
        File packagedArtifactFile = findInProjectLocalRepository(artifact);
        if (packagedArtifactFile != null
                && packagedArtifactFile.exists()

                    pluginDescriptor.getPlugin(),
                    "The plugin " + pluginDescriptor.getId() + " has unmet prerequisites: " + messages,
                    prerequisiteExceptions.get(0));
            // the first exception is added as cause, all other ones as suppressed exceptions
            prerequisiteExceptions.stream().skip(1).forEach(pie::addSuppressed);
            throw pie;
        }
    }

    @Override