NodeVisitState state = visitedNodes.get(node);
    if (state == NodeVisitState.COMPLETE) {
      return false;
    }
    if (state == NodeVisitState.PENDING) {
      return true;
    }

    visitedNodes.put(node, NodeVisitState.PENDING);
    for (N nextNode : graph.successors(node)) {
      if (canTraverseWithoutReusingEdge(graph, nextNode, previousNode)

@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
abstract class LineBuffer {
  /** Holds partial line contents. */
  private StringBuilder line = new StringBuilder();
  /** Whether a line ending with a CR is pending processing. */
  private boolean sawReturn;

  /**
   * Process additional characters from the stream. When a line separator is found the contents of

https://github.com/google/guava/wiki/HowToContribute#code-contributions
and
https://github.com/google/guava/blob/master/CONTRIBUTING.md
before sending a pull request.

We generally welcome PRs for fixing trivial bugs or typos, but please refrain
from sending a PR with significant changes unless explicitly requested.

    private final CountDownLatch stopLatch = new CountDownLatch(1);

    private volatile boolean running = false;

    @Override
    public @Nullable Void call() throws InterruptedException {
      running = true;
      startLatch.countDown();
      stopLatch.await();
      running = false;
      return null;
    }

    public void waitForStart() throws InterruptedException {

    private final CountDownLatch stopLatch = new CountDownLatch(1);

    private volatile boolean running = false;

    @Override
    public @Nullable Void call() throws InterruptedException {
      running = true;
      startLatch.countDown();
      stopLatch.await();
      running = false;
      return null;
    }

    public void waitForStart() throws InterruptedException {

  <exclude name="**/testing/**"/>
</source>

<!--
    We used to set this only for packages that had manual supersource. That
    worked everywhere that I know of except for one place: when running the GWT
    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see https://goo.gl/pRV3Yn for details.

  <exclude name="**/testing/**"/>
</source>

<!--
    We used to set this only for packages that had manual supersource. That
    worked everywhere that I know of except for one place: when running the GWT
    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see https://goo.gl/pRV3Yn for details.

  <exclude name="**/testing/**"/>
</source>

<!--
    We used to set this only for packages that had manual supersource. That
    worked everywhere that I know of except for one place: when running the GWT
    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see https://goo.gl/pRV3Yn for details.

          }
          // Log it and keep going.
          logger
              .get()
              .log(
                  Level.SEVERE,
                  "Exception while running callbacks for " + listener + " on " + executor,
                  e);
          throw e;
        }
      }
    }

    @Override
    @SuppressWarnings("CatchingUnchecked") // sneaky checked exception

   * com.google.common.testing.junit4.TearDownTestCase} for example.
   *
   * <p>A failing {@link TearDown} may or may not fail a tl4j test, depending on the version of
   * JUnit test case you are running under. To avoid failing in the face of an exception regardless
   * of JUnit version, implement a {@link SloppyTearDown} instead.
   *
   * <p>tl4j details: For backwards compatibility, {@code junit3.TearDownTestCase} currently does