Export of internal Abseil changes

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066144400e12616f6771e512427bcd98aa203455 by Abseil Team <absl-team@google.com>:

Internal comment cleanup.

PiperOrigin-RevId: 377368470

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3ba56d263bd90a9797d12b5ce29edce3fa65917c by Abseil Team <absl-team@google.com>:

Add tests for hash table capacity being unchanged by insert.

PiperOrigin-RevId: 377303140
GitOrigin-RevId: 066144400e12616f6771e512427bcd98aa203455
Change-Id: I2edf14b412e45a2ad490dcf9f06e009c12a60e3e

4 files changed, 103 insertions, 7 deletions

diff --git a/absl/container/internal/raw_hash_map.h b/absl/container/internal/raw_hash_map.h
index 0a02757d..c7df2efc 100644
--- a/absl/container/internal/raw_hash_map.h
+++ b/absl/container/internal/raw_hash_map.h
@@ -51,8 +51,9 @@ class raw_hash_map : public raw_hash_set<Policy, Hash, Eq, Alloc> {
   using key_arg = typename KeyArgImpl::template type<K, key_type>;
 
   static_assert(!std::is_reference<key_type>::value, "");
-  // TODO(alkis): remove this assertion and verify that reference mapped_type is
-  // supported.
+
+  // TODO(b/187807849): Evaluate whether to support reference mapped_type and
+  // remove this assertion if/when it is supported.
   static_assert(!std::is_reference<mapped_type>::value, "");
 
   using iterator = typename raw_hash_map::raw_hash_set::iterator;
diff --git a/absl/container/internal/raw_hash_set_test.cc b/absl/container/internal/raw_hash_set_test.cc
index 7dac65a0..af882ef4 100644
--- a/absl/container/internal/raw_hash_set_test.cc
+++ b/absl/container/internal/raw_hash_set_test.cc
@@ -541,6 +541,37 @@ TEST(Table, InsertCollisionAndFindAfterDelete) {
   EXPECT_TRUE(t.empty());
 }
 
+TEST(Table, InsertWithinCapacity) {
+  IntTable t;
+  t.reserve(10);
+  const size_t original_capacity = t.capacity();
+  const auto addr = [&](int i) {
+    return reinterpret_cast<uintptr_t>(&*t.find(i));
+  };
+  // Inserting an element does not change capacity.
+  t.insert(0);
+  EXPECT_THAT(t.capacity(), original_capacity);
+  const uintptr_t original_addr_0 = addr(0);
+  // Inserting another element does not rehash.
+  t.insert(1);
+  EXPECT_THAT(t.capacity(), original_capacity);
+  EXPECT_THAT(addr(0), original_addr_0);
+  // Inserting lots of duplicate elements does not rehash.
+  for (int i = 0; i < 100; ++i) {
+    t.insert(i % 10);
+  }
+  EXPECT_THAT(t.capacity(), original_capacity);
+  EXPECT_THAT(addr(0), original_addr_0);
+  // Inserting a range of duplicate elements does not rehash.
+  std::vector<int> dup_range;
+  for (int i = 0; i < 100; ++i) {
+    dup_range.push_back(i % 10);
+  }
+  t.insert(dup_range.begin(), dup_range.end());
+  EXPECT_THAT(t.capacity(), original_capacity);
+  EXPECT_THAT(addr(0), original_addr_0);
+}
+
 TEST(Table, LazyEmplace) {
   StringTable t;
   bool called = false;
diff --git a/absl/container/internal/unordered_map_modifiers_test.h b/absl/container/internal/unordered_map_modifiers_test.h
index 8c9ca779..d3543936 100644
--- a/absl/container/internal/unordered_map_modifiers_test.h
+++ b/absl/container/internal/unordered_map_modifiers_test.h
@@ -81,6 +81,38 @@ TYPED_TEST_P(ModifiersTest, InsertRange) {
   ASSERT_THAT(items(m), ::testing::UnorderedElementsAreArray(values));
 }
 
+TYPED_TEST_P(ModifiersTest, InsertWithinCapacity) {
+  using T = hash_internal::GeneratedType<TypeParam>;
+  using V = typename TypeParam::mapped_type;
+  T val = hash_internal::Generator<T>()();
+  TypeParam m;
+  m.reserve(10);
+  const size_t original_capacity = m.bucket_count();
+  m.insert(val);
+  EXPECT_EQ(m.bucket_count(), original_capacity);
+  T val2 = {val.first, hash_internal::Generator<V>()()};
+  m.insert(val2);
+  EXPECT_EQ(m.bucket_count(), original_capacity);
+}
+
+TYPED_TEST_P(ModifiersTest, InsertRangeWithinCapacity) {
+#if !defined(__GLIBCXX__)
+  using T = hash_internal::GeneratedType<TypeParam>;
+  std::vector<T> base_values;
+  std::generate_n(std::back_inserter(base_values), 10,
+                  hash_internal::Generator<T>());
+  std::vector<T> values;
+  while (values.size() != 100) {
+    std::copy_n(base_values.begin(), 10, std::back_inserter(values));
+  }
+  TypeParam m;
+  m.reserve(10);
+  const size_t original_capacity = m.bucket_count();
+  m.insert(values.begin(), values.end());
+  EXPECT_EQ(m.bucket_count(), original_capacity);
+#endif
+}
+
 TYPED_TEST_P(ModifiersTest, InsertOrAssign) {
 #ifdef UNORDERED_MAP_CXX17
   using std::get;
@@ -266,9 +298,10 @@ TYPED_TEST_P(ModifiersTest, Swap) {
 // TODO(alkis): Write tests for merge.
 
 REGISTER_TYPED_TEST_CASE_P(ModifiersTest, Clear, Insert, InsertHint,
-                           InsertRange, InsertOrAssign, InsertOrAssignHint,
-                           Emplace, EmplaceHint, TryEmplace, TryEmplaceHint,
-                           Erase, EraseRange, EraseKey, Swap);
+                           InsertRange, InsertWithinCapacity,
+                           InsertRangeWithinCapacity, InsertOrAssign,
+                           InsertOrAssignHint, Emplace, EmplaceHint, TryEmplace,
+                           TryEmplaceHint, Erase, EraseRange, EraseKey, Swap);
 
 template <typename Type>
 struct is_unique_ptr : std::false_type {};
diff --git a/absl/container/internal/unordered_set_modifiers_test.h b/absl/container/internal/unordered_set_modifiers_test.h
index 26be58d9..6e473e45 100644
--- a/absl/container/internal/unordered_set_modifiers_test.h
+++ b/absl/container/internal/unordered_set_modifiers_test.h
@@ -74,6 +74,36 @@ TYPED_TEST_P(ModifiersTest, InsertRange) {
   ASSERT_THAT(keys(m), ::testing::UnorderedElementsAreArray(values));
 }
 
+TYPED_TEST_P(ModifiersTest, InsertWithinCapacity) {
+  using T = hash_internal::GeneratedType<TypeParam>;
+  T val = hash_internal::Generator<T>()();
+  TypeParam m;
+  m.reserve(10);
+  const size_t original_capacity = m.bucket_count();
+  m.insert(val);
+  EXPECT_EQ(m.bucket_count(), original_capacity);
+  m.insert(val);
+  EXPECT_EQ(m.bucket_count(), original_capacity);
+}
+
+TYPED_TEST_P(ModifiersTest, InsertRangeWithinCapacity) {
+#if !defined(__GLIBCXX__)
+  using T = hash_internal::GeneratedType<TypeParam>;
+  std::vector<T> base_values;
+  std::generate_n(std::back_inserter(base_values), 10,
+                  hash_internal::Generator<T>());
+  std::vector<T> values;
+  while (values.size() != 100) {
+    values.insert(values.end(), base_values.begin(), base_values.end());
+  }
+  TypeParam m;
+  m.reserve(10);
+  const size_t original_capacity = m.bucket_count();
+  m.insert(values.begin(), values.end());
+  EXPECT_EQ(m.bucket_count(), original_capacity);
+#endif
+}
+
 TYPED_TEST_P(ModifiersTest, Emplace) {
   using T = hash_internal::GeneratedType<TypeParam>;
   T val = hash_internal::Generator<T>()();
@@ -180,8 +210,9 @@ TYPED_TEST_P(ModifiersTest, Swap) {
 // TODO(alkis): Write tests for merge.
 
 REGISTER_TYPED_TEST_CASE_P(ModifiersTest, Clear, Insert, InsertHint,
-                           InsertRange, Emplace, EmplaceHint, Erase, EraseRange,
-                           EraseKey, Swap);
+                           InsertRange, InsertWithinCapacity,
+                           InsertRangeWithinCapacity, Emplace, EmplaceHint,
+                           Erase, EraseRange, EraseKey, Swap);
 
 }  // namespace container_internal
 ABSL_NAMESPACE_END