}
        assertThat(
                graph.predecessors(node).contains(adjacentNode)
                    || graph.successors(node).contains(adjacentNode))
            .isTrue();
      }

      for (N predecessor : sanityCheckSet(graph.predecessors(node))) {
        assertThat(graph.successors(predecessor)).contains(node);
        assertThat(graph.hasEdgeConnecting(predecessor, node)).isTrue();

        return org;
    }

    private BuildStep merge(BuildStep node1, BuildStep node2) {
        node1.predecessors.addAll(node2.predecessors);
        node1.successors.addAll(node2.successors);
        node2.mojos.forEach((k, v) -> node1.mojos.merge(k, v, this::mergeMojos));
        return node1;
    }

        }
        assertThat(
                graph.predecessors(node).contains(adjacentNode)
                    || graph.successors(node).contains(adjacentNode))
            .isTrue();
      }

      for (N predecessor : sanityCheckSet(graph.predecessors(node))) {
        assertThat(graph.successors(predecessor)).contains(node);
        assertThat(graph.hasEdgeConnecting(predecessor, node)).isTrue();

                        writer.accept("\tPhase:         " + step.name);
                        if (!step.predecessors.isEmpty()) {
                            writer.accept("\tPredecessors:  "
                                    + nonEmptyPredecessors(step)
                                            .map(n -> phase(project, n, plan.duplicateIds()))

                        })
                        .orElse(false);

                // Check if any predecessor failed - if so, we'll run the step but mark it as SKIPPED
                boolean anyPredecessorFailed = step.predecessors.stream().anyMatch(s -> s.status.get() == FAILED);

                // If any predecessor failed, we'll use a special status transition: CREATED -> SKIPPED

 * which has a method {@code getParents()} that retrieves its predecessors in a graph:
 *
 * {@snippet :
 * someGraphAlgorithm(startNode, MyNode::getParents);
 * }
 *
 * <p>If you have some other mechanism for returning the predecessors of a node, or one that doesn't
 * return a {@code Iterable<? extends N>}, then you can use a lambda to perform a more general

                      Iterators.transform(
                          graph.predecessors(node).iterator(),
                          (N predecessor) -> EndpointPair.ordered(predecessor, node)),
                      Iterators.transform(
                          // filter out 'node' from successors (already covered by predecessors,
                          // above)

                for (Plugin element : tgt) {
                    Object key = getPluginKey(element);
                    master.put(key, element);
                }

                Map<Object, List<Plugin>> predecessors = new LinkedHashMap<>();
                List<Plugin> pending = new ArrayList<>();
                for (Plugin element : src) {
                    Object key = getPluginKey(element);

    @Nonnull
    final String name;

    @Nullable
    final Lifecycle.Phase phase;

    final Map<Integer, Map<String, MojoExecution>> mojos = new TreeMap<>();
    final Collection<BuildStep> predecessors = new HashSet<>();
    final Collection<BuildStep> successors = new HashSet<>();
    final AtomicInteger status = new AtomicInteger();
    final AtomicBoolean skip = new AtomicBoolean();
    volatile Exception exception;

    }

    private void assertIsSuccessor(BuildStep predecessor, BuildStep successor) {
        assertTrue(
                successor.isSuccessorOf(predecessor),
                String.format("Expected '%s' to be a successor of '%s'", successor.toString(), predecessor.toString()));
    }

    @SuppressWarnings("checkstyle:UnusedLocalVariable")