Executor executor) {
    return (FluentFuture<V>) Futures.catching(this, exceptionType, fallback, executor);
  }

  public final FluentFuture<V> catchingAsync(
      Class<Throwable> exceptionType,
      AsyncFunction<? super Throwable, ? extends V> fallback,
      Executor executor) {
    return (FluentFuture<V>) Futures.catchingAsync(this, exceptionType, fallback, executor);
  }

 * {@code GwtIncompatible}. This is more accurate for {@link Futures#catching}, which is available
 * under GWT but with a slightly different signature.
 *
 * <p>We can't use {@code PartiallyGwtIncompatible} because then the GWT compiler wouldn't recognize
 * it as a {@code GwtIncompatible} annotation. And for {@code Futures.catching}, we need the GWT

   * @return the implied set of features
   */
  public static Set<Feature<?>> impliedFeatures(Set<Feature<?>> features) {
    Set<Feature<?>> impliedSet = new LinkedHashSet<>();
    Queue<Feature<?>> queue = new ArrayDeque<>(features);
    while (!queue.isEmpty()) {
      Feature<?> feature = queue.remove();
      for (Feature<?> implied : feature.getImpliedFeatures()) {
        if (!features.contains(implied) && impliedSet.add(implied)) {

  }

  private static Set<Feature<?>> computeReserializedMapFeatures(Set<Feature<?>> mapFeatures) {
    Set<Feature<?>> derivedFeatures = copyToSet(mapFeatures);
    derivedFeatures.remove(CollectionFeature.SERIALIZABLE);
    derivedFeatures.remove(CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS);
    return derivedFeatures;
  }

  private static Set<Feature<?>> computeEntrySetFeatures(Set<Feature<?>> mapFeatures) {

 *
 * @author George van den Driessche
 */
@GwtCompatible
public final class TesterRequirements {
  private final Set<Feature<?>> presentFeatures;
  private final Set<Feature<?>> absentFeatures;

  public TesterRequirements(Set<Feature<?>> presentFeatures, Set<Feature<?>> absentFeatures) {
    this.presentFeatures = copyToSet(presentFeatures);
    this.absentFeatures = copyToSet(absentFeatures);
  }

              .withTearDown(parentBuilder.getTearDown())
              .createTestSuite());
    }

    return derived;
  }

  private static Set<Feature<?>> computeInverseFeatures(Set<Feature<?>> mapFeatures) {
    Set<Feature<?>> inverseFeatures = new HashSet<>(mapFeatures);

    boolean nullKeys = inverseFeatures.remove(MapFeature.ALLOWS_NULL_KEYS);

          annotationClass.getDeclaringClass(),
          returnType.getComponentType());
    }
  }

  // This is public so that tests for Feature enums we haven't yet imagined
  // can reuse it.
  public static <E extends Enum<?> & Feature<?>> void assertGoodFeatureEnum(
      Class<E> featureEnumClass) {
    Class<?>[] classes = featureEnumClass.getDeclaredClasses();
    for (Class<?> containedClass : classes) {

    }

    @Override
    public Nature getNature() {
        if (metadata instanceof RepositoryMetadata repositoryMetadata) {
            return switch (repositoryMetadata.getNature()) {
                case RepositoryMetadata.RELEASE_OR_SNAPSHOT -> Nature.RELEASE_OR_SNAPSHOT;
                case RepositoryMetadata.SNAPSHOT -> Nature.SNAPSHOT;
                default -> Nature.RELEASE;
            };
        } else {

import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import java.util.logging.Level;
import org.jspecify.annotations.Nullable;

/**
 * A helper which does some thread-safe operations for aggregate futures, which must be implemented
 * differently in GWT. Namely:
 *
 * <ul>
 *   <li>Lazily initializes a set of seen exceptions
 *   <li>Decrements a counter atomically
 * </ul>
 */
@GwtCompatible

 * {@code GwtIncompatible}. This is more accurate for {@link Futures#catching}, which is available
 * under GWT but with a slightly different signature.
 *
 * <p>We can't use {@code PartiallyGwtIncompatible} because then the GWT compiler wouldn't recognize
 * it as a {@code GwtIncompatible} annotation. And for {@code Futures.catching}, we need the GWT