* #copyOf(Multimap)}) instead preserves key-grouped order by inserting entries for an existing key
 * immediately after the last entry having that key.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible

import org.jspecify.annotations.Nullable;

/**
 * Static utility methods pertaining to {@code double} primitives, that are not already found in
 * either {@link Double} or {@link Arrays}.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
@GwtCompatible

---
title: "Go, Backwards Compatibility, and GODEBUG"
layout: article
---

<!--
This document is kept in the Go repo, not x/website,
because it documents the full list of known GODEBUG settings,
which are tied to a specific release.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.

 * are <i>lazy</i>, which means that their iterators only advance the backing iteration when
 * absolutely necessary.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#iterables">{@code
 * Iterables}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible

makes it unnecessary.

  3. Protecting Users' Legal Rights From Anti-Circumvention Law.

  No covered work shall be deemed part of an effective technological
measure under any applicable law fulfilling obligations under article
11 of the WIPO copyright treaty adopted on 20 December 1996, or
similar laws prohibiting or restricting circumvention of such
measures.

  When you convey a covered work, you waive any legal power to forbid

 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting
 * collection will not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Louis Wasserman
 * @since 12.0
 */
@GwtIncompatible // hasn't been tested yet

import org.jspecify.annotations.Nullable;

/**
 * Static utility methods pertaining to {@code long} primitives, that are not already found in
 * either {@link Long} or {@link Arrays}.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
@GwtCompatible
public final class Longs {
  private Longs() {}

 * {@link Comparable} class specification. Otherwise, the resulting multiset will violate the {@link
 * java.util.Collection} contract, which is specified in terms of {@link Object#equals}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multiset">{@code Multiset}</a>.
 *
 * @author Louis Wasserman
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible

 * retain all the configuration properties of the original cache. Note that the serialized form does
 * <i>not</i> include cache contents, but only configuration.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/CachesExplained">caching</a> for a higher-level
 * explanation.
 *
 * @param <K> the most general key type this builder will be able to create caches for. This is

 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting
 * collection will not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 * @since 2.0 (implements {@code NavigableSet} since 12.0)