Each file is a list of API features, one per line.

go1.txt (and similarly named files) are frozen once a version has been
shipped. Each file adds new lines but does not remove any.

except.txt lists features that may disappear without breaking true
compatibility.

Starting with go1.19.txt, each API feature line must end in "#nnnnn"
giving the GitHub issue number of the proposal issue that accepted

        type: choice
        options:
          - translate-page
          - translate-lang
          - update-outdated
          - add-missing
          - update-and-add
          - remove-all-removable
      language:
        description: Language to translate to as a letter code (e.g. "es" for Spanish)
        type: string
        required: false
        default: ""
      en_path:

    Set<Feature<?>> inverseFeatures = new HashSet<>(mapFeatures);

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

    if (nullKeys) {
      inverseFeatures.add(MapFeature.ALLOWS_NULL_VALUES);
    }
    if (nullValues) {

    assertTrue(result.remove(v0()));
    assertFalse(multimap().containsEntry(k0(), v0()));
    assertEquals(2, multimap().size());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testPropagatesRemoveLastElementToMultimap() {
    Collection<V> result = multimap().get(k0());
    assertTrue(result.remove(v0()));
    assertGet(k0());
  }

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testAsMapRemove() {
    assertContentsInOrder(multimap().asMap().remove(k0()), v0());
    assertGet(k0());
    assertEquals(getNumElements() - 1, multimap().size());
  }

  @CollectionSize.Require(SEVERAL)
  @MapFeature.Require(SUPPORTS_PUT)

    } else { // successor
      adjacentNodeValues.remove(node);
      removedValue = previousValue;
    }

    if (removedValue != null) {
      checkNonNegative(--successorCount);

      if (orderedNodeConnections != null) {
        orderedNodeConnections.remove(new NodeConnection.Succ<>((N) node));
      }
    }

    /*

    if (entryIterator.hasNext()) {
      Entry<E> result = entryIterator.next();
      result = Multisets.immutableEntry(result.getElement(), result.getCount());
      entryIterator.remove();
      return result;
    }
    return null;
  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {
    Iterator<Entry<E>> entryIterator = descendingEntryIterator();

import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * CompactHashMap is an implementation of a Map. All optional operations (put and remove) are
 * supported. Null keys and values are supported.
 *
 * <p>{@code containsKey(k)}, {@code put(k, v)} and {@code remove(k)} are all (expected and
 * amortized) constant time operations. Expected in the hashtable sense (depends on the hash

    editor.setString(0, "AB")
    editor.setString(1, "C")
    cache.close()
    val expected = if (windows) arrayOf("DIRTY k1") else arrayOf("DIRTY k1", "REMOVE k1")
    assertJournalEquals(*expected)
    editor.commit()
    assertJournalEquals(*expected) // 'REMOVE k1' not written because journal is closed.
  }

  @ParameterizedTest
  @ArgumentsSource(FileSystemParamProvider::class)

  }

  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) {