<img src="/img/deployment/https/https.svg">

The **TLS certificates** are **associated with a domain name**, not with an IP address.

So, to renew the certificates, the renewal program needs to **prove** to the authority (Let's Encrypt) that it indeed **"owns" and controls that domain**.

To do that, and to accommodate different application needs, there are several ways it can do it. Some popular ways are:

  }

  private static <K, V> ImmutableSortedMap<K, V> copyOfInternal(
      Map<? extends K, ? extends V> map, Comparator<? super K> comparator) {

    if (map instanceof ImmutableSortedMap) {
      // TODO: Prove that this cast is safe, even though
      // Collections.unmodifiableSortedMap requires the same key type.
      @SuppressWarnings("unchecked")
      ImmutableSortedMap<K, V> kvMap = (ImmutableSortedMap<K, V>) map;

<p>
If <code>list</code> pointed to a cyclic list,
then the original program would never access <code>*p</code> or <code>*q</code>,
but the rewritten program would.
(Moving `*p` ahead would be safe if the compiler can prove `*p` will not panic;
moving `*q` ahead would also require the compiler proving that no other
goroutine can access `*q`.)
</p>

<p>
Not introducing data races also means not assuming that called functions

        (a, b) -> {
          count.incrementAndGet();
          assertThat(a.equals(String.valueOf(b))).isTrue();
        });
    assertThat(count.get()).isEqualTo(100000);
    // of course, this test doesn't prove that anything actually happened in parallel...
  }

  // TODO(kevinb): switch to importing Truth's assertThat(DoubleStream) if we get that added
  private static IterableSubject assertThatDoubleStream(DoubleStream stream) {

TensorFlow coding style.

#### General guidelines and philosophy for contribution

*   Include unit tests when you contribute new features, as they help to a)
    prove that your code works correctly, and b) guard against future breaking
    changes to lower the maintenance cost.
*   Bug fixes also generally require unit tests, because the presence of bugs

      // even though K doesn't explicitly implement Comparable.
      comparator = (Comparator<? super K>) NATURAL_ORDER;
    }
    if (map instanceof ImmutableSortedMap) {
      // TODO(kevinb): Prove that this cast is safe, even though
      // Collections.unmodifiableSortedMap requires the same key type.
      @SuppressWarnings("unchecked")
      ImmutableSortedMap<K, V> kvMap = (ImmutableSortedMap<K, V>) map;

      // even though K doesn't explicitly implement Comparable.
      comparator = (Comparator<? super K>) NATURAL_ORDER;
    }
    if (map instanceof ImmutableSortedMap) {
      // TODO(kevinb): Prove that this cast is safe, even though
      // Collections.unmodifiableSortedMap requires the same key type.
      @SuppressWarnings("unchecked")
      ImmutableSortedMap<K, V> kvMap = (ImmutableSortedMap<K, V>) map;

        verifyScenario(alteration.mutate(scenario), level + 1);
      }
    }
  }

  /**
   * An aggregation of an ordering with a list (of size > 1) that should prove to be in strictly
   * increasing order according to that ordering.
   */
  private static class Scenario<T extends @Nullable Object> {
    final Ordering<T> ordering;
    final List<T> strictlyOrderedList;

        verifyScenario(alteration.mutate(scenario), level + 1);
      }
    }
  }

  /**
   * An aggregation of an ordering with a list (of size > 1) that should prove to be in strictly
   * increasing order according to that ordering.
   */
  private static class Scenario<T extends @Nullable Object> {
    final Ordering<T> ordering;
    final List<T> strictlyOrderedList;

    assertEquals("bar", Iterables.getLast(iterable, "qux"));
  }

  /**
   * {@link ArrayList} extension that forbids the use of {@link Collection#iterator} for tests that
   * need to prove that it isn't called.
   */
  private static class DiesOnIteratorArrayList extends ArrayList<String> {
    /** @throws UnsupportedOperationException all the time */
    @Override
    public Iterator<String> iterator() {