}

        return pluginManager.getMojoDescriptor(
                plugin, goal, project.getRemotePluginRepositories(), session.getRepositorySession());
    }

    // TODO take repo mans into account as one may be aggregating prefixes of many
    // TODO collect at the root of the repository, read the one at the root, and fetch remote if something is missing
    // or the user forces the issue

   *       terminate whichever thread happens to trigger the execution.
   * </ul>
   *
   * A specific warning about locking: Code that executes user-supplied tasks, such as {@code
   * ListenableFuture} listeners, should take care not to do so while holding a lock. Additionally,
   * as a further line of defense, prefer not to perform any locking inside a task that will be run

    throw new NoSuchMethodError(methodName);
  }

  @Override
  public void run() {
    assertSame(this, Thread.currentThread());
    try {
      while (true) {
        Request request = requestQueue.take();
        Object result;
        try {
          result = invokeMethod(request.methodName, request.arguments);
        } catch (ThreadDeath death) {
          return;

    int elements = Queues.drain(q, buf, -1, MAX_VALUE, NANOSECONDS);
    assertEquals(0, elements);
    assertThat(buf).isEmpty();

    // Free the producer thread, and give subsequent tests a clean slate.
    q.take();
  }

  public void testDrain_throws() throws Exception {
    for (BlockingQueue<Object> q : blockingQueues()) {
      testDrain_throws(q);
    }
  }

     * all other executions until finished.
     * We also lock on a given project to forbid a forked lifecycle to be executed concurrently with the project.
     * TODO: ideally, the builder should take care of the ordering in a smarter way
     * TODO: and concurrency issues fixed with MNG-7157
     */
    private class ProjectLock implements AutoCloseable {
        final Lock acquiredAggregatorLock;

    ImmutableSet.Builder<ImmutableList<Class<?>>> allOverloads = ImmutableSet.builder();
    // The first two are for the overloads that don't take formatting args, e.g.
    // checkArgument(boolean) and checkArgument(boolean, Object)
    allOverloads.add(ImmutableList.<Class<?>>of(predicateType));
    allOverloads.add(ImmutableList.<Class<?>>of(predicateType, Object.class));

    List<?> exp = copyToList(expected);
    List<?> act = copyToList(actual);
    String actString = act.toString();

    // Of course we could take pains to give the complete description of the
    // problem on any failure.

    // Yeah it's n^2.
    for (Object object : exp) {
      if (!act.remove(object)) {
        Assert.fail(

      successorFunction.successors(node); // Will throw if node doesn't exist
    }
    return copy;
  }

  /**
   * Abstracts away the difference between traversing a graph vs. a tree. For a tree, we just take
   * the next element from the next non-empty iterator; for graph, we need to loop through the next
   * non-empty iterator to find first unvisited node.
   */
  private abstract static class Traversal<N> {

   * throw an exception in response to any of {@code elements} being null or of the wrong type.
   *
   * <p><b>Note:</b> this method does not take into account the occurrence count of an element in
   * the two collections; it may still return {@code true} even if {@code elements} contains several

            boolean isBlankVersion = descriptor.getRequiredMavenVersion() == null
                    || descriptor.getRequiredMavenVersion().trim().isEmpty();

            if (isBlankVersion) {
                // only take value from underlying POM if plugin descriptor has no explicit Maven requirement
                descriptor.setRequiredMavenVersion(artifact.getProperty("requiredMavenVersion", null));
            }