return acl;
              }
            };
        return () -> attribute;
      } catch (IOException e) {
        // We throw a new exception each time so that the stack trace is right.
        return () -> {
          throw new IOException("Could not find user", e);
        };
      }
    }

    private static String getUsername() {
      /*

     *
     * @param content
     * @param error
     */
    void debug(CharSequence content, Throwable error);

    /**
     * Send an exception to the user in the <b>debug</b> error level.<br>
     * The stack trace for this exception will be output when this error level is enabled.
     *
     * @param error
     */
    void debug(Throwable error);

    void debug(Supplier<String> content);

    /**
     * Helper class to traverse graph. Required to make the containing method thread-safe
     * and yet use class level data to lessen stack usage in recursion
     */
    private class ClasspathGraphVisitor {
        MetadataGraph graph;

        ClasspathContainer cpc;

        List<MetadataGraphVertex> visited;

 *
 * This is because the ModelProcessor interface extends ModelLocator and ModelReader. If we
 * made this component available under all its interfaces then it could end up being injected
 * into itself leading to a stack overflow.
 *
 * A side effect of using @Typed is that it translates to explicit bindings in the container.
 * So instead of binding the component under a 'wildcard' key it is now bound with an explicit

 *
 * <pre>{@code
 * // Helper function keeps victim stack-unreachable.
 * private WeakReference<Foo> fooWeakRef() {
 *   Foo x = ....;
 *   WeakReference<Foo> weakRef = new WeakReference<>(x);
 *   // ... use x ...
 *   x = null;  // Hint to the JIT that x is stack-unreachable
 *   return weakRef;
 * }
 * public void testFooLeak() {
 *   GcFinalization.awaitClear(fooWeakRef());

      fail();
    } catch (CancellationException expected) {
      // There should be two CancellationException chained together.  The outer one should have the
      // stack trace of where the get() call was made, and the inner should have the stack trace of
      // where the immediateCancelledFuture() call was made.
      List<StackTraceElement> stackTrace = ImmutableList.copyOf(expected.getStackTrace());

      setFutureSuccess.set(false);
      cancellationSuccess.set(false);
      finalResults.clear();
    }
    executor.shutdown();
  }

  // In a previous implementation this would cause a stack overflow after ~2000 futures chained
  // together.  Now it should only be limited by available memory (and time)
  public void testSetFuture_stackOverflow() {
    SettableFuture<String> orig = SettableFuture.create();

      setFutureSuccess.set(false);
      cancellationSuccess.set(false);
      finalResults.clear();
    }
    executor.shutdown();
  }

  // In a previous implementation this would cause a stack overflow after ~2000 futures chained
  // together.  Now it should only be limited by available memory (and time)
  public void testSetFuture_stackOverflow() {
    SettableFuture<String> orig = SettableFuture.create();

                    }
                  },
                  service);
        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {

                    }
                  },
                  service);
        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {