Fix cord handling in DynamicMessage and oneofs.

This fixes a memory corruption vulnerability for anyone using cord with dynamically built descriptor pools.

PiperOrigin-RevId: 676091224

.bazelrc

@@ -26,6 +26,8 @@ build:ubsan --action_env=UBSAN_OPTIONS=halt_on_error=1:print_stacktrace=1
 # Workaround for the fact that Bazel links with $CC, not $CXX
 # https://github.com/bazelbuild/bazel/issues/11122#issuecomment-613746748
 build:ubsan --copt=-fno-sanitize=function --copt=-fno-sanitize=vptr
+# Abseil passes nullptr to memcmp with 0 size
+build:ubsan --copt=-fno-sanitize=nonnull-attribute
 
 # TODO: migrate all dependencies from WORKSPACE to MODULE.bazel
 # https://github.com/protocolbuffers/protobuf/issues/14313

ci/common.bazelrc

@@ -31,6 +31,8 @@ build:ubsan --action_env=UBSAN_OPTIONS=halt_on_error=1:print_stacktrace=1
 # Workaround for the fact that Bazel links with $CC, not $CXX
 # https://github.com/bazelbuild/bazel/issues/11122#issuecomment-613746748
 build:ubsan --copt=-fno-sanitize=function --copt=-fno-sanitize=vptr
+# Abseil passes nullptr to memcmp with 0 size
+build:ubsan --copt=-fno-sanitize=nonnull-attribute
 
 # Workaround Bazel 7 remote cache issues.
 # See https://github.com/bazelbuild/bazel/issues/20161

python/google/protobuf/internal/descriptor_test.py

@@ -727,7 +727,7 @@ class GeneratedDescriptorTest(unittest.TestCase):
     excepted_dict['new_key'] = 'new'
     self.assertNotEqual(mapping, excepted_dict)
     self.assertRaises(KeyError, mapping.__getitem__, 'key_error')
-    self.assertRaises(KeyError, mapping.__getitem__, len(mapping) + 1)
+    self.assertRaises(KeyError, mapping.__getitem__, len(mapping) * 2)
     # TODO: Add __repr__ support for DescriptorMapping.
     if api_implementation.Type() == 'cpp':
       self.assertEqual(str(mapping)[0], '<')

python/google/protobuf/internal/field_mask_test.py

@@ -53,7 +53,7 @@ class FieldMaskTest(unittest.TestCase):
     mask = field_mask_pb2.FieldMask()
     msg_descriptor = unittest_pb2.TestAllTypes.DESCRIPTOR
     mask.AllFieldsFromDescriptor(msg_descriptor)
-    self.assertEqual(79, len(mask.paths))
+    self.assertEqual(80, len(mask.paths))
     self.assertTrue(mask.IsValidForDescriptor(msg_descriptor))
     for field in msg_descriptor.fields:
       self.assertTrue(field.name in mask.paths)

python/google/protobuf/internal/test_util.py

@@ -77,6 +77,7 @@ def SetAllNonLazyFields(message):
 
   message.optional_string_piece = u'124'
   message.optional_cord = u'125'
+  message.optional_bytes_cord = b'optional bytes cord'
 
   #
   # Repeated fields.
@@ -247,6 +248,7 @@ def SetAllExtensions(message):
 
   extensions[pb2.optional_string_piece_extension] = u'124'
   extensions[pb2.optional_cord_extension] = u'125'
+  extensions[pb2.optional_bytes_cord_extension] = b'optional bytes cord'
 
   #
   # Repeated fields.
@@ -423,6 +425,7 @@ def ExpectAllFieldsSet(test_case, message):
 
   test_case.assertTrue(message.HasField('optional_string_piece'))
   test_case.assertTrue(message.HasField('optional_cord'))
+  test_case.assertTrue(message.HasField('optional_bytes_cord'))
 
   test_case.assertEqual(101, message.optional_int32)
   test_case.assertEqual(102, message.optional_int64)

python/google/protobuf/internal/unknown_fields_test.py

@@ -212,7 +212,7 @@ class UnknownFieldsAccessorsTest(unittest.TestCase):
                            unknown_field_set,
                            (17, 0, 117))
 
-    self.assertEqual(98, len(unknown_field_set))
+    self.assertEqual(99, len(unknown_field_set))
 
   def testCopyFrom(self):
     message = unittest_pb2.TestEmptyMessage()
@@ -250,7 +250,7 @@ class UnknownFieldsAccessorsTest(unittest.TestCase):
     self.empty_message.Clear()
     # All cleared, even unknown fields.
     self.assertEqual(self.empty_message.SerializeToString(), b'')
-    self.assertEqual(len(unknown_field_set), 98)
+    self.assertEqual(len(unknown_field_set), 99)
 
   @unittest.skipIf((sys.version_info.major, sys.version_info.minor) < (3, 4),
                    'tracemalloc requires python 3.4+')
@@ -309,7 +309,7 @@ class UnknownFieldsAccessorsTest(unittest.TestCase):
   def testUnknownExtensions(self):
     message = unittest_pb2.TestEmptyMessageWithExtensions()
     message.ParseFromString(self.all_fields_data)
-    self.assertEqual(len(unknown_fields.UnknownFieldSet(message)), 98)
+    self.assertEqual(len(unknown_fields.UnknownFieldSet(message)), 99)
     self.assertEqual(message.SerializeToString(), self.all_fields_data)
 
 

src/google/protobuf/compiler/cpp/field.cc

@@ -130,7 +130,6 @@ FieldGeneratorBase::FieldGeneratorBase(const FieldDescriptor* field,
       break;
     case FieldDescriptor::CPPTYPE_STRING:
       is_string_ = true;
-      string_type_ = field->options().ctype();
       is_inlined_ = IsStringInlined(field, options);
       is_bytes_ = field->type() == FieldDescriptor::TYPE_BYTES;
       has_default_constexpr_constructor_ = is_repeated_or_map;
@@ -229,40 +228,6 @@ void FieldGeneratorBase::GenerateCopyConstructorCode(io::Printer* p) const {
 }
 
 namespace {
-// Use internal types instead of ctype or string_type.
-enum class StringType {
-  kView,
-  kString,
-  kCord,
-  kStringPiece,
-};
-
-StringType GetStringType(const FieldDescriptor& field) {
-  ABSL_CHECK_EQ(field.cpp_type(), FieldDescriptor::CPPTYPE_STRING);
-
-  if (field.options().has_ctype()) {
-    switch (field.options().ctype()) {
-      case FieldOptions::CORD:
-        return StringType::kCord;
-      case FieldOptions::STRING_PIECE:
-        return StringType::kStringPiece;
-      default:
-        return StringType::kString;
-    }
-  }
-
-  const pb::CppFeatures& cpp_features =
-      CppGenerator::GetResolvedSourceFeatures(field).GetExtension(::pb::cpp);
-  switch (cpp_features.string_type()) {
-    case pb::CppFeatures::CORD:
-      return StringType::kCord;
-    case pb::CppFeatures::VIEW:
-      return StringType::kView;
-    default:
-      return StringType::kString;
-  }
-}
-
 std::unique_ptr<FieldGeneratorBase> MakeGenerator(const FieldDescriptor* field,
                                                   const Options& options,
                                                   MessageSCCAnalyzer* scc) {
@@ -279,7 +244,7 @@ std::unique_ptr<FieldGeneratorBase> MakeGenerator(const FieldDescriptor* field,
       case FieldDescriptor::CPPTYPE_MESSAGE:
         return MakeRepeatedMessageGenerator(field, options, scc);
       case FieldDescriptor::CPPTYPE_STRING: {
-        if (GetStringType(*field) == StringType::kView) {
+        if (field->cpp_string_type() == FieldDescriptor::CppStringType::kView) {
           return MakeRepeatedStringViewGenerator(field, options, scc);
         } else {
           return MakeRepeatedStringGenerator(field, options, scc);
@@ -303,10 +268,10 @@ std::unique_ptr<FieldGeneratorBase> MakeGenerator(const FieldDescriptor* field,
     case FieldDescriptor::CPPTYPE_ENUM:
       return MakeSinguarEnumGenerator(field, options, scc);
     case FieldDescriptor::CPPTYPE_STRING: {
-      switch (GetStringType(*field)) {
-        case StringType::kView:
+      switch (field->cpp_string_type()) {
+        case FieldDescriptor::CppStringType::kView:
           return MakeSingularStringViewGenerator(field, options, scc);
-        case StringType::kCord:
+        case FieldDescriptor::CppStringType::kCord:
           if (field->type() == FieldDescriptor::TYPE_BYTES) {
             if (field->real_containing_oneof()) {
               return MakeOneofCordGenerator(field, options, scc);

src/google/protobuf/compiler/cpp/field.h

@@ -95,9 +95,6 @@ class FieldGeneratorBase {
   // Returns true if the field API uses bytes (void) instead of chars.
   bool is_bytes() const { return is_bytes_; }
 
-  // Returns the public API string type for string fields.
-  FieldOptions::CType string_type() const { return string_type_; }
-
   // Returns true if this field is part of a oneof field.
   bool is_oneof() const { return is_oneof_; }
 
@@ -217,7 +214,6 @@ class FieldGeneratorBase {
   bool is_lazy_ = false;
   bool is_weak_ = false;
   bool is_oneof_ = false;
-  FieldOptions::CType string_type_ = FieldOptions::STRING;
   bool has_default_constexpr_constructor_ = false;
 };
 
@@ -269,7 +265,6 @@ class FieldGenerator {
   bool is_foreign() const { return impl_->is_foreign(); }
   bool is_string() const { return impl_->is_string(); }
   bool is_bytes() const { return impl_->is_bytes(); }
-  FieldOptions::CType string_type() const { return impl_->string_type(); }
   bool is_oneof() const { return impl_->is_oneof(); }
   bool is_inlined() const { return impl_->is_inlined(); }
   bool has_default_constexpr_constructor() const {

src/google/protobuf/compiler/cpp/field_generators/string_view_field.cc

@@ -216,8 +216,6 @@ void SingularStringView::GenerateStaticMembers(io::Printer* p) const {
 }
 
 void SingularStringView::GenerateAccessorDeclarations(io::Printer* p) const {
-  ABSL_CHECK(!field_->options().has_ctype());
-
   auto v1 = p->WithVars(AnnotatedAccessors(field_, {""}));
   auto v2 = p->WithVars(
       AnnotatedAccessors(field_, {"set_"}, AnnotationCollector::kSet));

src/google/protobuf/compiler/cpp/helpers.cc

@@ -1597,7 +1597,8 @@ MessageAnalysis MessageSCCAnalyzer::GetSCCAnalysis(const SCC* scc) {
       switch (field->type()) {
         case FieldDescriptor::TYPE_STRING:
         case FieldDescriptor::TYPE_BYTES: {
-          if (field->options().ctype() == FieldOptions::CORD) {
+          if (field->cpp_string_type() ==
+              FieldDescriptor::CppStringType::kCord) {
             result.contains_cord = true;
           }
           break;

src/google/protobuf/compiler/cpp/tracker.cc

@@ -221,7 +221,8 @@ Getters RepeatedFieldGetters(const FieldDescriptor* field,
 
 Getters StringFieldGetters(const FieldDescriptor* field, const Options& opts) {
   std::string member = FieldMemberName(field, ShouldSplit(field, opts));
-  bool is_std_string = field->options().ctype() == FieldOptions::STRING;
+  bool is_std_string =
+      field->cpp_string_type() == FieldDescriptor::CppStringType::kString;
 
   Getters getters;
   if (is_std_string && !field->default_value_string().empty()) {
@@ -241,7 +242,8 @@ Getters StringOneofGetters(const FieldDescriptor* field,
   ABSL_CHECK(oneof != nullptr);
 
   std::string member = FieldMemberName(field, ShouldSplit(field, opts));
-  bool is_std_string = field->options().ctype() == FieldOptions::STRING;
+  bool is_std_string =
+      field->cpp_string_type() == FieldDescriptor::CppStringType::kString;
 
   std::string field_ptr = member;
   if (is_std_string) {
@@ -258,8 +260,8 @@ Getters StringOneofGetters(const FieldDescriptor* field,
   }
 
   Getters getters;
-  if (field->default_value_string().empty() ||
-      field->options().ctype() == FieldOptions::STRING_PIECE) {
+  if (field->default_value_string().empty()
+  ) {
     getters.base = absl::Substitute("$0 ? $1 : nullptr", has, field_ptr);
   } else {
     getters.base =

src/google/protobuf/compiler/cpp/unittest.inc

@@ -428,6 +428,7 @@ TEST(GENERATED_MESSAGE_TEST_NAME, SwapWithOther) {
   message1.set_optional_string("abc");
   message1.mutable_optional_nested_message()->set_bb(1);
   message1.set_optional_nested_enum(UNITTEST::TestAllTypes::FOO);
+  message1.set_optional_bytes_cord("bytes cord");
   message1.add_repeated_int32(1);
   message1.add_repeated_int32(2);
   message1.add_repeated_string("a");
@@ -441,6 +442,7 @@ TEST(GENERATED_MESSAGE_TEST_NAME, SwapWithOther) {
   message2.set_optional_string("def");
   message2.mutable_optional_nested_message()->set_bb(2);
   message2.set_optional_nested_enum(UNITTEST::TestAllTypes::BAR);
+  message2.set_optional_bytes_cord("bytes cord");
   message2.add_repeated_int32(3);
   message2.add_repeated_string("c");
   message2.add_repeated_nested_message()->set_bb(9);
@@ -452,6 +454,7 @@ TEST(GENERATED_MESSAGE_TEST_NAME, SwapWithOther) {
   EXPECT_EQ("def", message1.optional_string());
   EXPECT_EQ(2, message1.optional_nested_message().bb());
   EXPECT_EQ(UNITTEST::TestAllTypes::BAR, message1.optional_nested_enum());
+  EXPECT_EQ(absl::Cord("bytes cord"), message1.optional_bytes_cord());
   ASSERT_EQ(1, message1.repeated_int32_size());
   EXPECT_EQ(3, message1.repeated_int32(0));
   ASSERT_EQ(1, message1.repeated_string_size());
@@ -465,6 +468,7 @@ TEST(GENERATED_MESSAGE_TEST_NAME, SwapWithOther) {
   EXPECT_EQ("abc", message2.optional_string());
   EXPECT_EQ(1, message2.optional_nested_message().bb());
   EXPECT_EQ(UNITTEST::TestAllTypes::FOO, message2.optional_nested_enum());
+  EXPECT_EQ(absl::Cord("bytes cord"), message2.optional_bytes_cord());
   ASSERT_EQ(2, message2.repeated_int32_size());
   EXPECT_EQ(1, message2.repeated_int32(0));
   EXPECT_EQ(2, message2.repeated_int32(1));

src/google/protobuf/descriptor.h

@@ -2954,7 +2954,8 @@ PROTOBUF_EXPORT bool HasHasbit(const FieldDescriptor* field);
 template <typename FieldDesc = FieldDescriptor,
           typename FieldOpts = FieldOptions>
 typename FieldOpts::CType EffectiveStringCType(const FieldDesc* field) {
-  // TODO Replace this function with FieldDescriptor::string_type;
+  // TODO Replace this function with
+  // FieldDescriptor::cpp_string_type;
   switch (field->cpp_string_type()) {
     case FieldDescriptor::CppStringType::kCord:
       return FieldOpts::CORD;

src/google/protobuf/descriptor_unittest.cc

@@ -7571,7 +7571,7 @@ TEST_F(FeaturesTest, Proto2Features) {
         name: "cord"
         number: 8
         label: LABEL_OPTIONAL
-        type: TYPE_STRING
+        type: TYPE_BYTES
         options { ctype: CORD }
       }
       field {
@@ -7656,6 +7656,8 @@ TEST_F(FeaturesTest, Proto2Features) {
 
   EXPECT_EQ(message->FindFieldByName("str")->cpp_string_type(),
             FieldDescriptor::CppStringType::kString);
+  EXPECT_EQ(message->FindFieldByName("cord")->cpp_string_type(),
+            FieldDescriptor::CppStringType::kCord);
 
   // Check round-trip consistency.
   FileDescriptorProto proto;

src/google/protobuf/dynamic_message.cc

@@ -117,9 +117,11 @@ int FieldSpaceUsed(const FieldDescriptor* field) {
         }
 
       case FD::CPPTYPE_STRING:
-        switch (field->options().ctype()) {
-          default:  // TODO:  Support other string reps.
-          case FieldOptions::STRING:
+        switch (field->cpp_string_type()) {
+          case FieldDescriptor::CppStringType::kCord:
+            return sizeof(RepeatedField<absl::Cord>);
+          case FieldDescriptor::CppStringType::kView:
+          case FieldDescriptor::CppStringType::kString:
             return sizeof(RepeatedPtrField<std::string>);
         }
         break;
@@ -147,9 +149,11 @@ int FieldSpaceUsed(const FieldDescriptor* field) {
         return sizeof(Message*);
 
       case FD::CPPTYPE_STRING:
-        switch (field->options().ctype()) {
-          default:  // TODO:  Support other string reps.
-          case FieldOptions::STRING:
+        switch (field->cpp_string_type()) {
+          case FieldDescriptor::CppStringType::kCord:
+            return sizeof(absl::Cord);
+          case FieldDescriptor::CppStringType::kView:
+          case FieldDescriptor::CppStringType::kString:
             return sizeof(ArenaStringPtr);
         }
         break;
@@ -399,9 +403,31 @@ void DynamicMessage::SharedCtor(bool lock_factory) {
         break;
 
       case FieldDescriptor::CPPTYPE_STRING:
-        switch (field->options().ctype()) {
-          default:  // TODO:  Support other string reps.
-          case FieldOptions::STRING:
+        switch (field->cpp_string_type()) {
+          case FieldDescriptor::CppStringType::kCord:
+            if (!field->is_repeated()) {
+              if (field->has_default_value()) {
+                new (field_ptr) absl::Cord(field->default_value_string());
+              } else {
+                new (field_ptr) absl::Cord;
+              }
+              if (arena != nullptr) {
+                // Cord does not support arena so here we need to notify arena
+                // to remove the data it allocated on the heap by calling its
+                // destructor.
+                arena->OwnDestructor(static_cast<absl::Cord*>(field_ptr));
+              }
+            } else {
+              new (field_ptr) RepeatedField<absl::Cord>(arena);
+              if (arena != nullptr) {
+                // Needs to destroy Cord elements.
+                arena->OwnDestructor(
+                    static_cast<RepeatedField<absl::Cord>*>(field_ptr));
+              }
+            }
+            break;
+          case FieldDescriptor::CppStringType::kView:
+          case FieldDescriptor::CppStringType::kString:
             if (!field->is_repeated()) {
               ArenaStringPtr* asp = new (field_ptr) ArenaStringPtr();
               asp->InitDefault();
@@ -491,9 +517,12 @@ DynamicMessage::~DynamicMessage() {
       if (*(reinterpret_cast<const int32_t*>(field_ptr)) == field->number()) {
         field_ptr = MutableOneofFieldRaw(field);
         if (field->cpp_type() == FieldDescriptor::CPPTYPE_STRING) {
-          switch (field->options().ctype()) {
-            default:
-            case FieldOptions::STRING: {
+          switch (field->cpp_string_type()) {
+            case FieldDescriptor::CppStringType::kCord:
+              delete *reinterpret_cast<absl::Cord**>(field_ptr);
+              break;
+            case FieldDescriptor::CppStringType::kView:
+            case FieldDescriptor::CppStringType::kString: {
               reinterpret_cast<ArenaStringPtr*>(field_ptr)->Destroy();
               break;
             }
@@ -525,9 +554,13 @@ DynamicMessage::~DynamicMessage() {
 #undef HANDLE_TYPE
 
         case FieldDescriptor::CPPTYPE_STRING:
-          switch (field->options().ctype()) {
-            default:  // TODO:  Support other string reps.
-            case FieldOptions::STRING:
+          switch (field->cpp_string_type()) {
+            case FieldDescriptor::CppStringType::kCord:
+              reinterpret_cast<RepeatedField<absl::Cord>*>(field_ptr)
+                  ->~RepeatedField<absl::Cord>();
+              break;
+            case FieldDescriptor::CppStringType::kView:
+            case FieldDescriptor::CppStringType::kString:
               reinterpret_cast<RepeatedPtrField<std::string>*>(field_ptr)
                   ->~RepeatedPtrField<std::string>();
               break;
@@ -545,9 +578,12 @@ DynamicMessage::~DynamicMessage() {
       }
 
     } else if (field->cpp_type() == FieldDescriptor::CPPTYPE_STRING) {
-      switch (field->options().ctype()) {
-        default:  // TODO:  Support other string reps.
-        case FieldOptions::STRING: {
+      switch (field->cpp_string_type()) {
+        case FieldDescriptor::CppStringType::kCord:
+          reinterpret_cast<absl::Cord*>(field_ptr)->~Cord();
+          break;
+        case FieldDescriptor::CppStringType::kView:
+        case FieldDescriptor::CppStringType::kString: {
           reinterpret_cast<ArenaStringPtr*>(field_ptr)->Destroy();
           break;
         }

src/google/protobuf/edition_unittest.proto

@@ -91,6 +91,7 @@ message TestAllTypes {
 
   string optional_string_piece = 24 [ctype=STRING_PIECE];
   string optional_cord = 25 [ctype=CORD];
+  bytes optional_bytes_cord = 86 [ctype=CORD];
 
   // Defined in unittest_import_public.proto
   protobuf_unittest_import.PublicImportMessage
@@ -266,6 +267,7 @@ extend TestAllExtensions {
   // TODO: ctype=CORD is not supported for extension. Add
   // ctype=CORD option back after it is supported.
   string optional_cord_extension = 25;
+  bytes optional_bytes_cord_extension = 86;
 
   protobuf_unittest_import.PublicImportMessage
     optional_public_import_message_extension = 26;

src/google/protobuf/generated_message_reflection.cc

@@ -403,9 +403,13 @@ size_t Reflection::SpaceUsedLong(const Message& message) const {
 #undef HANDLE_TYPE
 
         case FieldDescriptor::CPPTYPE_STRING:
-          switch (field->options().ctype()) {
-            default:  // TODO:  Support other string reps.
-            case FieldOptions::STRING:
+          switch (field->cpp_string_type()) {
+            case FieldDescriptor::CppStringType::kCord:
+              total_size += GetRaw<RepeatedField<absl::Cord>>(message, field)
+                                .SpaceUsedExcludingSelfLong();
+              break;
+            case FieldDescriptor::CppStringType::kView:
+            case FieldDescriptor::CppStringType::kString:
               total_size +=
                   GetRaw<RepeatedPtrField<std::string> >(message, field)
                       .SpaceUsedExcludingSelfLong();
@@ -444,8 +448,8 @@ size_t Reflection::SpaceUsedLong(const Message& message) const {
           break;
 
         case FieldDescriptor::CPPTYPE_STRING: {
-          switch (internal::cpp::EffectiveStringCType(field)) {
-            case FieldOptions::CORD:
+          switch (field->cpp_string_type()) {
+            case FieldDescriptor::CppStringType::kCord:
               if (schema_.InRealOneof(field)) {
                 total_size += GetField<absl::Cord*>(message, field)
                                   ->EstimatedMemoryUsage();
@@ -457,8 +461,8 @@ size_t Reflection::SpaceUsedLong(const Message& message) const {
                               sizeof(absl::Cord);
               }
               break;
-            default:
-            case FieldOptions::STRING:
+            case FieldDescriptor::CppStringType::kView:
+            case FieldDescriptor::CppStringType::kString:
               if (IsInlined(field)) {
                 const std::string* ptr =
                     &GetField<InlinedStringField>(message, field).GetNoArena();
@@ -554,15 +558,14 @@ struct OneofFieldMover {
           to->SetString(from->GetString());
           break;
         }
-        switch (internal::cpp::EffectiveStringCType(field)) {
-          case FieldOptions::CORD:
+        switch (field->cpp_string_type()) {
+          case FieldDescriptor::CppStringType::kCord:
             to->SetCord(from->GetCord());
             break;
-          default:
-          case FieldOptions::STRING: {
+          case FieldDescriptor::CppStringType::kView:
+          case FieldDescriptor::CppStringType::kString:
             to->SetArenaStringPtr(from->GetArenaStringPtr());
             break;
-          }
         }
         break;
       default:
@@ -625,9 +628,19 @@ template <bool unsafe_shallow_swap>
 void SwapFieldHelper::SwapRepeatedStringField(const Reflection* r, Message* lhs,
                                               Message* rhs,
                                               const FieldDescriptor* field) {
-  switch (field->options().ctype()) {
-    default:
-    case FieldOptions::STRING: {
+  switch (field->cpp_string_type()) {
+    case FieldDescriptor::CppStringType::kCord: {
+      auto* lhs_cord = r->MutableRaw<RepeatedField<absl::Cord>>(lhs, field);
+      auto* rhs_cord = r->MutableRaw<RepeatedField<absl::Cord>>(rhs, field);
+      if (unsafe_shallow_swap) {
+        lhs_cord->InternalSwap(rhs_cord);
+      } else {
+        lhs_cord->Swap(rhs_cord);
+      }
+      break;
+    }
+    case FieldDescriptor::CppStringType::kView:
+    case FieldDescriptor::CppStringType::kString: {
       auto* lhs_string = r->MutableRaw<RepeatedPtrFieldBase>(lhs, field);
       auto* rhs_string = r->MutableRaw<RepeatedPtrFieldBase>(rhs, field);
       if (unsafe_shallow_swap) {
@@ -691,14 +704,14 @@ template <bool unsafe_shallow_swap>
 void SwapFieldHelper::SwapStringField(const Reflection* r, Message* lhs,
                                       Message* rhs,
                                       const FieldDescriptor* field) {
-  switch (internal::cpp::EffectiveStringCType(field)) {
-    case FieldOptions::CORD:
+  switch (field->cpp_string_type()) {
+    case FieldDescriptor::CppStringType::kCord:
       // Always shallow swap for Cord.
       std::swap(*r->MutableRaw<absl::Cord>(lhs, field),
                 *r->MutableRaw<absl::Cord>(rhs, field));
       break;
-    default:
-    case FieldOptions::STRING: {
+    case FieldDescriptor::CppStringType::kView:
+    case FieldDescriptor::CppStringType::kString: {
       if (r->IsInlined(field)) {
         SwapFieldHelper::SwapInlinedStrings<unsafe_shallow_swap>(r, lhs, rhs,
                                                                  field);
@@ -1162,7 +1175,9 @@ void Reflection::SwapFieldsImpl(
         // may depend on the information in has bits.
         if (!field->is_repeated()) {
           SwapHasBit(message1, message2, field);
-          if (field->options().ctype() == FieldOptions::STRING &&
+          if (field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
+              field->cpp_string_type() ==
+                  FieldDescriptor::CppStringType::kString &&
               IsInlined(field)) {
             ABSL_DCHECK(!unsafe_shallow_swap ||
                         message1->GetArena() == message2->GetArena());
@@ -1276,9 +1291,10 @@ void Reflection::InternalSwap(Message* lhs, Message* rhs) const {
     int inlined_string_count = 0;
     for (int i = 0; i < descriptor_->field_count(); i++) {
       const FieldDescriptor* field = descriptor_->field(i);
+      if (field->cpp_type() != FieldDescriptor::CPPTYPE_STRING) continue;
       if (field->is_extension() || field->is_repeated() ||
           schema_.InRealOneof(field) ||
-          field->options().ctype() != FieldOptions::STRING ||
+          field->cpp_string_type() != FieldDescriptor::CppStringType::kString ||
           !IsInlined(field)) {
         continue;
       }
@@ -1330,6 +1346,10 @@ int Reflection::FieldSize(const Message& message,
 #undef HANDLE_TYPE
 
       case FieldDescriptor::CPPTYPE_STRING:
+        if (field->cpp_string_type() == FieldDescriptor::CppStringType::kCord) {
+          return GetRaw<RepeatedField<absl::Cord> >(message, field).size();
+        }
+        ABSL_FALLTHROUGH_INTENDED;
       case FieldDescriptor::CPPTYPE_MESSAGE:
         if (IsMapFieldInApi(field)) {
           const internal::MapFieldBase& map =
@@ -1388,8 +1408,8 @@ void Reflection::ClearField(Message* message,
           break;
 
         case FieldDescriptor::CPPTYPE_STRING: {
-          switch (internal::cpp::EffectiveStringCType(field)) {
-            case FieldOptions::CORD:
+          switch (field->cpp_string_type()) {
+            case FieldDescriptor::CppStringType::kCord:
               if (field->has_default_value()) {
                 *MutableRaw<absl::Cord>(message, field) =
                     field->default_value_string();
@@ -1397,8 +1417,8 @@ void Reflection::ClearField(Message* message,
                 MutableRaw<absl::Cord>(message, field)->Clear();
               }
               break;
-            default:
-            case FieldOptions::STRING:
+            case FieldDescriptor::CppStringType::kView:
+            case FieldDescriptor::CppStringType::kString:
               if (IsInlined(field)) {
                 // Currently, string with default value can't be inlined. So we
                 // don't have to handle default value here.
@@ -1445,9 +1465,12 @@ void Reflection::ClearField(Message* message,
 #undef HANDLE_TYPE
 
       case FieldDescriptor::CPPTYPE_STRING: {
-        switch (field->options().ctype()) {
-          default:  // TODO:  Support other string reps.
-          case FieldOptions::STRING:
+        switch (field->cpp_string_type()) {
+          case FieldDescriptor::CppStringType::kCord:
+            MutableRaw<RepeatedField<absl::Cord>>(message, field)->Clear();
+            break;
+          case FieldDescriptor::CppStringType::kView:
+          case FieldDescriptor::CppStringType::kString:
             MutableRaw<RepeatedPtrField<std::string> >(message, field)->Clear();
             break;
         }
@@ -1495,9 +1518,12 @@ void Reflection::RemoveLast(Message* message,
 #undef HANDLE_TYPE
 
       case FieldDescriptor::CPPTYPE_STRING:
-        switch (field->options().ctype()) {
-          default:  // TODO:  Support other string reps.
-          case FieldOptions::STRING:
+        switch (field->cpp_string_type()) {
+          case FieldDescriptor::CppStringType::kCord:
+            MutableRaw<RepeatedField<absl::Cord>>(message, field)->RemoveLast();
+            break;
+          case FieldDescriptor::CppStringType::kView:
+          case FieldDescriptor::CppStringType::kString:
             MutableRaw<RepeatedPtrField<std::string> >(message, field)
                 ->RemoveLast();
             break;
@@ -1589,6 +1615,12 @@ void Reflection::SwapElements(Message* message, const FieldDescriptor* field,
 #undef HANDLE_TYPE
 
       case FieldDescriptor::CPPTYPE_STRING:
+        if (field->cpp_string_type() == FieldDescriptor::CppStringType::kCord) {
+          MutableRaw<RepeatedField<absl::Cord> >(message, field)
+              ->SwapElements(index1, index2);
+          break;
+        }
+        ABSL_FALLTHROUGH_INTENDED;
       case FieldDescriptor::CPPTYPE_MESSAGE:
         if (IsMapFieldInApi(field)) {
           MutableRaw<MapFieldBase>(message, field)
@@ -1795,15 +1827,15 @@ std::string Reflection::GetString(const Message& message,
     if (schema_.InRealOneof(field) && !HasOneofField(message, field)) {
       return std::string(field->default_value_string());
     }
-    switch (internal::cpp::EffectiveStringCType(field)) {
-      case FieldOptions::CORD:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
         if (schema_.InRealOneof(field)) {
           return std::string(*GetField<absl::Cord*>(message, field));
         } else {
           return std::string(GetField<absl::Cord>(message, field));
         }
-      default:
-      case FieldOptions::STRING:
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString:
         if (IsInlined(field)) {
           return GetField<InlinedStringField>(message, field).GetNoArena();
         } else {
@@ -1812,6 +1844,7 @@ std::string Reflection::GetString(const Message& message,
                                  : str.Get();
         }
     }
+    internal::Unreachable();
   }
 }
 
@@ -1827,8 +1860,8 @@ const std::string& Reflection::GetStringReference(const Message& message,
     if (schema_.InRealOneof(field) && !HasOneofField(message, field)) {
       return internal::DefaultValueStringAsString(field);
     }
-    switch (internal::cpp::EffectiveStringCType(field)) {
-      case FieldOptions::CORD:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
         if (schema_.InRealOneof(field)) {
           absl::CopyCordToString(*GetField<absl::Cord*>(message, field),
                                  scratch);
@@ -1836,8 +1869,8 @@ const std::string& Reflection::GetStringReference(const Message& message,
           absl::CopyCordToString(GetField<absl::Cord>(message, field), scratch);
         }
         return *scratch;
-      default:
-      case FieldOptions::STRING:
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString:
         if (IsInlined(field)) {
           return GetField<InlinedStringField>(message, field).GetNoArena();
         } else {
@@ -1846,6 +1879,7 @@ const std::string& Reflection::GetStringReference(const Message& message,
                                  : str.Get();
         }
     }
+    internal::Unreachable();
   }
 }
 
@@ -1859,15 +1893,15 @@ absl::Cord Reflection::GetCord(const Message& message,
     if (schema_.InRealOneof(field) && !HasOneofField(message, field)) {
       return absl::Cord(field->default_value_string());
     }
-    switch (internal::cpp::EffectiveStringCType(field)) {
-      case FieldOptions::CORD:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
         if (schema_.InRealOneof(field)) {
           return *GetField<absl::Cord*>(message, field);
         } else {
           return GetField<absl::Cord>(message, field);
         }
-      default:
-      case FieldOptions::STRING:
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString:
         if (IsInlined(field)) {
           return absl::Cord(
               GetField<InlinedStringField>(message, field).GetNoArena());
@@ -1877,9 +1911,7 @@ absl::Cord Reflection::GetCord(const Message& message,
                                             : str.Get());
         }
     }
-
-    ABSL_LOG(FATAL) << "Can't get here.";
-    return absl::Cord();  // Make compiler happy.
+    internal::Unreachable();
   }
 }
 
@@ -1896,8 +1928,8 @@ absl::string_view Reflection::GetStringView(const Message& message,
     return field->default_value_string();
   }
 
-  switch (internal::cpp::EffectiveStringCType(field)) {
-    case FieldOptions::CORD: {
+  switch (field->cpp_string_type()) {
+    case FieldDescriptor::CppStringType::kCord: {
       const auto& cord = schema_.InRealOneof(field)
                              ? *GetField<absl::Cord*>(message, field)
                              : GetField<absl::Cord>(message, field);
@@ -1917,8 +1949,8 @@ void Reflection::SetString(Message* message, const FieldDescriptor* field,
     return MutableExtensionSet(message)->SetString(
         field->number(), field->type(), std::move(value), field);
   } else {
-    switch (internal::cpp::EffectiveStringCType(field)) {
-      case FieldOptions::CORD:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
         if (schema_.InRealOneof(field)) {
           if (!HasOneofField(*message, field)) {
             ClearOneof(message, field->containing_oneof());
@@ -1930,8 +1962,8 @@ void Reflection::SetString(Message* message, const FieldDescriptor* field,
         }
         *MutableField<absl::Cord>(message, field) = value;
         break;
-      default:
-      case FieldOptions::STRING: {
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString: {
         if (IsInlined(field)) {
           const uint32_t index = schema_.InlinedStringIndex(field);
           ABSL_DCHECK_GT(index, 0u);
@@ -1969,8 +2001,8 @@ void Reflection::SetString(Message* message, const FieldDescriptor* field,
                                   MutableExtensionSet(message)->MutableString(
                                       field->number(), field->type(), field));
   } else {
-    switch (internal::cpp::EffectiveStringCType(field)) {
-      case FieldOptions::CORD:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
         if (schema_.InRealOneof(field)) {
           if (!HasOneofField(*message, field)) {
             ClearOneof(message, field->containing_oneof());
@@ -1982,8 +2014,8 @@ void Reflection::SetString(Message* message, const FieldDescriptor* field,
           *MutableField<absl::Cord>(message, field) = value;
         }
         break;
-      default:
-      case FieldOptions::STRING: {
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString: {
         // Oneof string fields are never set as a default instance.
         // We just need to pass some arbitrary default string to make it work.
         // This allows us to not have the real default accessible from
@@ -2019,11 +2051,14 @@ std::string Reflection::GetRepeatedString(const Message& message,
   if (field->is_extension()) {
     return GetExtensionSet(message).GetRepeatedString(field->number(), index);
   } else {
-    switch (field->options().ctype()) {
-      default:  // TODO:  Support other string reps.
-      case FieldOptions::STRING:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
+        return std::string(GetRepeatedField<absl::Cord>(message, field, index));
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString:
         return GetRepeatedPtrField<std::string>(message, field, index);
     }
+    internal::Unreachable();
   }
 }
 
@@ -2035,11 +2070,16 @@ const std::string& Reflection::GetRepeatedStringReference(
   if (field->is_extension()) {
     return GetExtensionSet(message).GetRepeatedString(field->number(), index);
   } else {
-    switch (field->options().ctype()) {
-      default:  // TODO:  Support other string reps.
-      case FieldOptions::STRING:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
+        absl::CopyCordToString(
+            GetRepeatedField<absl::Cord>(message, field, index), scratch);
+        return *scratch;
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString:
         return GetRepeatedPtrField<std::string>(message, field, index);
     }
+    internal::Unreachable();
   }
 }
 
@@ -2054,11 +2094,16 @@ absl::string_view Reflection::GetRepeatedStringView(
     return GetExtensionSet(message).GetRepeatedString(field->number(), index);
   }
 
-  switch (internal::cpp::EffectiveStringCType(field)) {
-    case FieldOptions::STRING:
-    default:
+  switch (field->cpp_string_type()) {
+    case FieldDescriptor::CppStringType::kCord: {
+      auto& cord = GetRepeatedField<absl::Cord>(message, field, index);
+      return scratch.CopyFromCord(cord);
+    }
+    case FieldDescriptor::CppStringType::kView:
+    case FieldDescriptor::CppStringType::kString:
       return GetRepeatedPtrField<std::string>(message, field, index);
   }
+  internal::Unreachable();
 }
 
 
@@ -2070,9 +2115,12 @@ void Reflection::SetRepeatedString(Message* message,
     MutableExtensionSet(message)->SetRepeatedString(field->number(), index,
                                                     std::move(value));
   } else {
-    switch (field->options().ctype()) {
-      default:  // TODO:  Support other string reps.
-      case FieldOptions::STRING:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
+        SetRepeatedField<absl::Cord>(message, field, index, absl::Cord(value));
+        break;
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString:
         MutableRepeatedField<std::string>(message, field, index)
             ->assign(std::move(value));
         break;
@@ -2088,9 +2136,12 @@ void Reflection::AddString(Message* message, const FieldDescriptor* field,
     MutableExtensionSet(message)->AddString(field->number(), field->type(),
                                             std::move(value), field);
   } else {
-    switch (field->options().ctype()) {
-      default:  // TODO:  Support other string reps.
-      case FieldOptions::STRING:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
+        AddField<absl::Cord>(message, field, absl::Cord(value));
+        break;
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString:
         AddField<std::string>(message, field)->assign(std::move(value));
         break;
     }
@@ -2618,7 +2669,8 @@ const void* Reflection::GetRawRepeatedField(const Message& message,
     ReportReflectionUsageTypeError(descriptor_, field, "GetRawRepeatedField",
                                    cpptype);
   if (ctype >= 0)
-    ABSL_CHECK_EQ(field->options().ctype(), ctype) << "subtype mismatch";
+    ABSL_CHECK_EQ(internal::cpp::EffectiveStringCType(field), ctype)
+        << "subtype mismatch";
   if (desc != nullptr)
     ABSL_CHECK_EQ(field->message_type(), desc) << "wrong submessage type";
   if (field->is_extension()) {
@@ -2744,7 +2796,7 @@ static Type* AllocIfDefault(const FieldDescriptor* field, Type*& ptr,
     // be e.g. char).
     if (field->cpp_type() < FieldDescriptor::CPPTYPE_STRING ||
         (field->cpp_type() == FieldDescriptor::CPPTYPE_STRING &&
-         internal::cpp::EffectiveStringCType(field) == FieldOptions::CORD)) {
+         field->cpp_string_type() == FieldDescriptor::CppStringType::kCord)) {
       ptr =
           reinterpret_cast<Type*>(Arena::Create<RepeatedField<int32_t>>(arena));
     } else {
@@ -2923,11 +2975,11 @@ bool Reflection::HasFieldSingular(const Message& message,
     // (which uses HasField()) needs to be consistent with this.
     switch (field->cpp_type()) {
       case FieldDescriptor::CPPTYPE_STRING:
-        switch (internal::cpp::EffectiveStringCType(field)) {
-          case FieldOptions::CORD:
+        switch (field->cpp_string_type()) {
+          case FieldDescriptor::CppStringType::kCord:
             return !GetField<const absl::Cord>(message, field).empty();
-          default:
-          case FieldOptions::STRING: {
+          case FieldDescriptor::CppStringType::kView:
+          case FieldDescriptor::CppStringType::kString: {
             if (IsInlined(field)) {
               return !GetField<InlinedStringField>(message, field)
                           .GetNoArena()
@@ -2937,7 +2989,7 @@ bool Reflection::HasFieldSingular(const Message& message,
             return GetField<ArenaStringPtr>(message, field).Get().size() > 0;
           }
         }
-        return false;
+        internal::Unreachable();
       case FieldDescriptor::CPPTYPE_BOOL:
         return GetRaw<bool>(message, field) != false;
       case FieldDescriptor::CPPTYPE_INT32:
@@ -3039,12 +3091,12 @@ void Reflection::ClearOneof(Message* message,
     if (message->GetArena() == nullptr) {
       switch (field->cpp_type()) {
         case FieldDescriptor::CPPTYPE_STRING: {
-          switch (internal::cpp::EffectiveStringCType(field)) {
-            case FieldOptions::CORD:
+          switch (field->cpp_string_type()) {
+            case FieldDescriptor::CppStringType::kCord:
               delete *MutableRaw<absl::Cord*>(message, field);
               break;
-            default:
-            case FieldOptions::STRING: {
+            case FieldDescriptor::CppStringType::kView:
+            case FieldDescriptor::CppStringType::kString: {
               // Oneof string fields are never set as a default instance.
               // We just need to pass some arbitrary default string to make it
               // work. This allows us to not have the real default accessible

src/google/protobuf/generated_message_tctable_gen.cc

@@ -167,10 +167,10 @@ TailCallTableInfo::FastFieldInfo::Field MakeFastFieldEntry(
    : field->is_repeated() ? PROTOBUF_PICK_FUNCTION(fn##R) \
                           : PROTOBUF_PICK_FUNCTION(fn##S))
 
-#define PROTOBUF_PICK_STRING_FUNCTION(fn)                       \
-  (field->options().ctype() == FieldOptions::CORD               \
-       ? PROTOBUF_PICK_FUNCTION(fn##cS)                         \
-   : options.is_string_inlined ? PROTOBUF_PICK_FUNCTION(fn##iS) \
+#define PROTOBUF_PICK_STRING_FUNCTION(fn)                            \
+  (field->cpp_string_type() == FieldDescriptor::CppStringType::kCord \
+       ? PROTOBUF_PICK_FUNCTION(fn##cS)                              \
+   : options.is_string_inlined ? PROTOBUF_PICK_FUNCTION(fn##iS)      \
                                : PROTOBUF_PICK_REPEATABLE_FUNCTION(fn))
 
   const FieldDescriptor* field = entry.field;
@@ -303,10 +303,12 @@ bool IsFieldEligibleForFastParsing(
   switch (field->type()) {
       // Some bytes fields can be handled on fast path.
     case FieldDescriptor::TYPE_STRING:
-    case FieldDescriptor::TYPE_BYTES:
-      if (field->options().ctype() == FieldOptions::STRING) {
+    case FieldDescriptor::TYPE_BYTES: {
+      auto ctype = field->cpp_string_type();
+      if (ctype == FieldDescriptor::CppStringType::kString ||
+          ctype == FieldDescriptor::CppStringType::kView) {
         // strings are fine...
-      } else if (field->options().ctype() == FieldOptions::CORD) {
+      } else if (ctype == FieldDescriptor::CppStringType::kCord) {
         // Cords are worth putting into the fast table, if they're not repeated
         if (field->is_repeated()) return false;
       } else {
@@ -320,6 +322,7 @@ bool IsFieldEligibleForFastParsing(
         aux_idx = entry.inlined_string_idx;
       }
       break;
+    }
 
     case FieldDescriptor::TYPE_ENUM: {
       uint8_t rmax_value;
@@ -758,12 +761,13 @@ uint16_t MakeTypeCardForField(
   // Fill in extra information about string and bytes field representations.
   if (field->type() == FieldDescriptor::TYPE_BYTES ||
       field->type() == FieldDescriptor::TYPE_STRING) {
-    switch (internal::cpp::EffectiveStringCType(field)) {
-      case FieldOptions::CORD:
+    switch (field->cpp_string_type()) {
+      case FieldDescriptor::CppStringType::kCord:
         // `Cord` is always used, even for repeated fields.
         type_card |= fl::kRepCord;
         break;
-      case FieldOptions::STRING:
+      case FieldDescriptor::CppStringType::kView:
+      case FieldDescriptor::CppStringType::kString:
         if (field->is_repeated()) {
           // A repeated string field uses RepeatedPtrField<std::string>
           // (unless it has a ctype option; see above).
@@ -773,8 +777,6 @@ uint16_t MakeTypeCardForField(
           type_card |= fl::kRepAString;
         }
         break;
-      default:
-        Unreachable();
     }
   }
 

src/google/protobuf/generated_message_tctable_lite.cc

@@ -1647,6 +1647,12 @@ bool TcParser::ChangeOneof(const TcParseTableBase* table,
         field.Destroy();
         break;
       }
+      case field_layout::kRepCord: {
+        if (msg->GetArena() == nullptr) {
+          delete RefAt<absl::Cord*>(msg, current_entry->offset);
+        }
+        break;
+      }
       case field_layout::kRepSString:
       case field_layout::kRepIString:
       default:

src/google/protobuf/lite_unittest.cc

@@ -960,6 +960,18 @@ TYPED_TEST(LiteTest, AllLite43) {
     EXPECT_TRUE(message2.MergeFromCodedStream(&input_stream));
     EXPECT_EQ(17, message2.oneof_int32());
   }
+
+  // Bytes [ctype = CORD]
+  {
+    protobuf_unittest::TestOneofParsingLite message2;
+    message2.set_oneof_bytes_cord("bytes cord");
+    io::CodedInputStream input_stream(
+        reinterpret_cast<const ::uint8_t*>(serialized.data()),
+        serialized.size());
+    EXPECT_TRUE(message2.MergeFromCodedStream(&input_stream));
+    EXPECT_EQ(17, message2.oneof_int32());
+  }
+
 }
 
 // Verify that we can successfully parse fields of various types within oneof
@@ -1046,6 +1058,18 @@ TYPED_TEST(LiteTest, AllLite44) {
     }
   }
 
+  // Bytes [ctype = CORD]
+  {
+    protobuf_unittest::TestOneofParsingLite original;
+    original.set_oneof_bytes_cord("bytes cord");
+    std::string serialized;
+    EXPECT_TRUE(original.SerializeToString(&serialized));
+    protobuf_unittest::TestOneofParsingLite parsed;
+    EXPECT_TRUE(parsed.MergeFromString(serialized));
+    EXPECT_EQ("bytes cord", std::string(parsed.oneof_bytes_cord()));
+    EXPECT_TRUE(parsed.MergeFromString(serialized));
+  }
+
   std::cout << "PASS" << std::endl;
 }
 

src/google/protobuf/message.cc

@@ -477,9 +477,11 @@ const internal::RepeatedFieldAccessor* Reflection::RepeatedFieldAccessor(
     HANDLE_PRIMITIVE_TYPE(ENUM, int32_t)
 #undef HANDLE_PRIMITIVE_TYPE
     case FieldDescriptor::CPPTYPE_STRING:
-      switch (field->options().ctype()) {
-        default:
-        case FieldOptions::STRING:
+      switch (field->cpp_string_type()) {
+        case FieldDescriptor::CppStringType::kCord:
+          ABSL_LOG(FATAL) << "Repeated cords are not supported.";
+        case FieldDescriptor::CppStringType::kView:
+        case FieldDescriptor::CppStringType::kString:
           return GetSingleton<internal::RepeatedPtrFieldStringAccessor>();
       }
       break;

src/google/protobuf/test_util.h

@@ -224,6 +224,8 @@ inline void TestUtil::ReflectionTester::SetAllFieldsViaReflection(
 
   reflection->SetString(message, F("optional_string_piece"), "124");
   reflection->SetString(message, F("optional_cord"), "125");
+  reflection->SetString(message, F("optional_bytes_cord"),
+                        "optional bytes cord");
 
   sub_message =
       reflection->MutableMessage(message, F("optional_public_import_message"));
@@ -492,6 +494,7 @@ inline void TestUtil::ReflectionTester::ExpectAllFieldsSetViaReflection1(
 
   EXPECT_TRUE(reflection->HasField(message, F("optional_string_piece")));
   EXPECT_TRUE(reflection->HasField(message, F("optional_cord")));
+  EXPECT_TRUE(reflection->HasField(message, F("optional_bytes_cord")));
 
   EXPECT_EQ(101, reflection->GetInt32(message, F("optional_int32")));
   EXPECT_EQ(102, reflection->GetInt64(message, F("optional_int64")));
@@ -553,6 +556,14 @@ inline void TestUtil::ReflectionTester::ExpectAllFieldsSetViaReflection1(
   EXPECT_EQ("125", reflection->GetStringReference(message, F("optional_cord"),
                                                   &scratch));
 
+  EXPECT_EQ("optional bytes cord",
+            reflection->GetString(message, F("optional_bytes_cord")));
+  EXPECT_EQ("optional bytes cord",
+            reflection->GetStringReference(message, F("optional_bytes_cord"),
+                                           &scratch));
+  EXPECT_EQ("optional bytes cord",
+            reflection->GetCord(message, F("optional_bytes_cord")));
+
   EXPECT_TRUE(reflection->HasField(message, F("oneof_bytes")));
   EXPECT_EQ("604", reflection->GetString(message, F("oneof_bytes")));
 
@@ -913,6 +924,7 @@ inline void TestUtil::ReflectionTester::ExpectClearViaReflection(
 
   EXPECT_FALSE(reflection->HasField(message, F("optional_string_piece")));
   EXPECT_FALSE(reflection->HasField(message, F("optional_cord")));
+  EXPECT_FALSE(reflection->HasField(message, F("optional_bytes_cord")));
 
   // Optional fields without defaults are set to zero or something like it.
   EXPECT_EQ(0, reflection->GetInt32(message, F("optional_int32")));
@@ -979,6 +991,11 @@ inline void TestUtil::ReflectionTester::ExpectClearViaReflection(
   EXPECT_EQ("", reflection->GetStringReference(message, F("optional_cord"),
                                                &scratch));
 
+  EXPECT_EQ("", reflection->GetString(message, F("optional_bytes_cord")));
+  EXPECT_EQ("", reflection->GetStringReference(
+                    message, F("optional_bytes_cord"), &scratch));
+  EXPECT_EQ("", reflection->GetCord(message, F("optional_bytes_cord")));
+
   // Repeated fields are empty.
   EXPECT_EQ(0, reflection->FieldSize(message, F("repeated_int32")));
   EXPECT_EQ(0, reflection->FieldSize(message, F("repeated_int64")));

src/google/protobuf/test_util.inc

@@ -140,6 +140,7 @@ inline void TestUtil::SetOptionalFields(UNITTEST::TestAllTypes* message) {
       message, message->GetDescriptor()->FindFieldByName("optional_cord"),
       "125");
 #endif  // !PROTOBUF_TEST_NO_DESCRIPTORS
+  message->set_optional_bytes_cord("optional bytes cord");
 }
 
 // -------------------------------------------------------------------
@@ -355,6 +356,7 @@ inline void TestUtil::ExpectAllFieldsSet(
   EXPECT_TRUE(message.has_optional_string_piece());
   EXPECT_TRUE(message.has_optional_cord());
 #endif
+  EXPECT_TRUE(message.has_optional_bytes_cord());
 
   EXPECT_EQ(101, message.optional_int32());
   EXPECT_EQ(102, message.optional_int64());
@@ -384,6 +386,7 @@ inline void TestUtil::ExpectAllFieldsSet(
   EXPECT_EQ(UNITTEST::FOREIGN_BAZ, message.optional_foreign_enum());
   EXPECT_EQ(UNITTEST_IMPORT::IMPORT_BAZ, message.optional_import_enum());
 
+  EXPECT_EQ("optional bytes cord", message.optional_bytes_cord());
 
   // -----------------------------------------------------------------
 
@@ -557,6 +560,7 @@ inline void TestUtil::ExpectClear(const UNITTEST::TestAllTypes& message) {
 
   EXPECT_FALSE(message.has_optional_string_piece());
   EXPECT_FALSE(message.has_optional_cord());
+  EXPECT_FALSE(message.has_optional_bytes_cord());
 
   // Optional fields without defaults are set to zero or something like it.
   EXPECT_EQ(0, message.optional_int32());
@@ -597,6 +601,7 @@ inline void TestUtil::ExpectClear(const UNITTEST::TestAllTypes& message) {
   EXPECT_EQ(UNITTEST::FOREIGN_FOO, message.optional_foreign_enum());
   EXPECT_EQ(UNITTEST_IMPORT::IMPORT_FOO, message.optional_import_enum());
 
+  EXPECT_EQ("", message.optional_bytes_cord());
 
   // Repeated fields are empty.
   EXPECT_EQ(0, message.repeated_int32_size());
@@ -978,6 +983,8 @@ inline void TestUtil::SetAllExtensions(UNITTEST::TestAllExtensions* message) {
 
   message->SetExtension(UNITTEST::optional_string_piece_extension, "124");
   message->SetExtension(UNITTEST::optional_cord_extension, "125");
+  message->SetExtension(UNITTEST::optional_bytes_cord_extension,
+                        "optional bytes cord");
 
   message->MutableExtension(UNITTEST::optional_public_import_message_extension)
       ->set_e(126);
@@ -1207,6 +1214,7 @@ inline void TestUtil::ExpectAllExtensionsSet(
 
   EXPECT_TRUE(message.HasExtension(UNITTEST::optional_string_piece_extension));
   EXPECT_TRUE(message.HasExtension(UNITTEST::optional_cord_extension));
+  EXPECT_TRUE(message.HasExtension(UNITTEST::optional_bytes_cord_extension));
 
   EXPECT_EQ(101, message.GetExtension(UNITTEST::optional_int32_extension));
   EXPECT_EQ(102, message.GetExtension(UNITTEST::optional_int64_extension));
@@ -1245,6 +1253,8 @@ inline void TestUtil::ExpectAllExtensionsSet(
   EXPECT_EQ("124",
             message.GetExtension(UNITTEST::optional_string_piece_extension));
   EXPECT_EQ("125", message.GetExtension(UNITTEST::optional_cord_extension));
+  EXPECT_EQ("optional bytes cord",
+            message.GetExtension(UNITTEST::optional_bytes_cord_extension));
   EXPECT_EQ(
       126,
       message.GetExtension(UNITTEST::optional_public_import_message_extension)
@@ -1493,6 +1503,7 @@ inline void TestUtil::ExpectExtensionsClear(
 
   EXPECT_FALSE(message.HasExtension(UNITTEST::optional_string_piece_extension));
   EXPECT_FALSE(message.HasExtension(UNITTEST::optional_cord_extension));
+  EXPECT_FALSE(message.HasExtension(UNITTEST::optional_bytes_cord_extension));
 
   // Optional fields without defaults are set to zero or something like it.
   EXPECT_EQ(0, message.GetExtension(UNITTEST::optional_int32_extension));
@@ -1560,6 +1571,7 @@ inline void TestUtil::ExpectExtensionsClear(
   EXPECT_EQ("",
             message.GetExtension(UNITTEST::optional_string_piece_extension));
   EXPECT_EQ("", message.GetExtension(UNITTEST::optional_cord_extension));
+  EXPECT_EQ("", message.GetExtension(UNITTEST::optional_bytes_cord_extension));
 
   // Repeated fields are empty.
   EXPECT_EQ(0, message.ExtensionSize(UNITTEST::repeated_int32_extension));

src/google/protobuf/testdata/text_format_unittest_data.txt

@@ -126,6 +126,7 @@ default_foreign_enum: FOREIGN_FOO
 default_import_enum: IMPORT_FOO
 default_string_piece: "424"
 default_cord: "425"
+optional_bytes_cord: "optional bytes cord"
 oneof_uint32: 601
 oneof_nested_message {
   bb: 602

src/google/protobuf/testdata/text_format_unittest_data_oneof_implemented.txt

@@ -129,4 +129,5 @@ default_foreign_enum: FOREIGN_FOO
 default_import_enum: IMPORT_FOO
 default_string_piece: "424"
 default_cord: "425"
+optional_bytes_cord: "optional bytes cord"
 oneof_bytes: "604"

src/google/protobuf/testdata/text_format_unittest_data_pointy.txt

@@ -129,6 +129,7 @@ default_foreign_enum: FOREIGN_FOO
 default_import_enum: IMPORT_FOO
 default_string_piece: "424"
 default_cord: "425"
+optional_bytes_cord: "optional bytes cord"
 oneof_uint32: 601
 oneof_nested_message <
   bb: 602

src/google/protobuf/testdata/text_format_unittest_data_pointy_oneof.txt

@@ -129,4 +129,5 @@ default_foreign_enum: FOREIGN_FOO
 default_import_enum: IMPORT_FOO
 default_string_piece: "424"
 default_cord: "425"
+optional_bytes_cord: "optional bytes cord"
 oneof_bytes: "604"

src/google/protobuf/testdata/text_format_unittest_extensions_data.txt

@@ -129,6 +129,7 @@
 [protobuf_unittest.default_import_enum_extension]: IMPORT_FOO
 [protobuf_unittest.default_string_piece_extension]: "424"
 [protobuf_unittest.default_cord_extension]: "425"
+[protobuf_unittest.optional_bytes_cord_extension]: "optional bytes cord"
 [protobuf_unittest.oneof_uint32_extension]: 601
 [protobuf_unittest.oneof_nested_message_extension] {
   bb: 602

src/google/protobuf/testdata/text_format_unittest_extensions_data_pointy.txt

@@ -129,6 +129,7 @@
 [protobuf_unittest.default_import_enum_extension]: IMPORT_FOO
 [protobuf_unittest.default_string_piece_extension]: "424"
 [protobuf_unittest.default_cord_extension]: "425"
+[protobuf_unittest.optional_bytes_cord_extension]: "optional bytes cord"
 [protobuf_unittest.oneof_uint32_extension]: 601
 [protobuf_unittest.oneof_nested_message_extension] <
   bb: 602

src/google/protobuf/unittest.proto

@@ -96,6 +96,7 @@ message TestAllTypes {
   string optional_cord = 25 [
     ctype = CORD
   ];
+  bytes optional_bytes_cord = 86 [ctype=CORD];
 
   // Defined in unittest_import_public.proto
   protobuf_unittest_import.PublicImportMessage optional_public_import_message = 26;
@@ -368,6 +369,8 @@ extend TestAllExtensions {
   // TODO: ctype=CORD is not supported for extension. Add
   // ctype=CORD option back after it is supported.
   string optional_cord_extension = 25;
+  bytes optional_bytes_cord_extension = 86;
+
   protobuf_unittest_import.PublicImportMessage
       optional_public_import_message_extension = 26;
   TestAllTypes.NestedMessage optional_lazy_message_extension = 27 [

src/google/protobuf/unittest_lite.proto

@@ -72,6 +72,7 @@ message TestAllTypesLite {
   string optional_string_piece = 24 [ctype = STRING_PIECE];
 
   string optional_cord = 25 [ctype = CORD];
+  bytes optional_bytes_cord = 86 [ctype = CORD];
 
   // Defined in unittest_import_public.proto
   protobuf_unittest_import.PublicImportMessageLite
@@ -261,6 +262,7 @@ extend TestAllExtensionsLite {
   // TODO: ctype=CORD is not supported for extension. Add
   // ctype=CORD option back after it is supported.
   string optional_cord_extension_lite = 25;
+  bytes optional_bytes_cord_extension_lite = 86;
   protobuf_unittest_import.PublicImportMessageLite
       optional_public_import_message_extension_lite = 26;
   TestAllTypesLite.NestedMessage optional_lazy_message_extension_lite = 27

src/google/protobuf/unittest_proto3_arena.proto

@@ -67,6 +67,7 @@ message TestAllTypes {
 
   string optional_string_piece = 24 [ctype=STRING_PIECE];
   string optional_cord = 25 [ctype=CORD];
+  bytes optional_bytes_cord = 86 [ctype=CORD];
 
   // Defined in unittest_import_public.proto
   protobuf_unittest_import.PublicImportMessage

src/google/protobuf/util/field_mask_util_test.cc

@@ -202,7 +202,7 @@ TEST(FieldMaskUtilTest, TestGetFieldMaskForAllFields) {
   EXPECT_TRUE(FieldMaskUtil::IsPathInFieldMask("bb", mask));
 
   mask = FieldMaskUtil::GetFieldMaskForAllFields<TestAllTypes>();
-  EXPECT_EQ(79, mask.paths_size());
+  EXPECT_EQ(80, mask.paths_size());
   EXPECT_TRUE(FieldMaskUtil::IsPathInFieldMask("optional_int32", mask));
   EXPECT_TRUE(FieldMaskUtil::IsPathInFieldMask("optional_int64", mask));
   EXPECT_TRUE(FieldMaskUtil::IsPathInFieldMask("optional_uint32", mask));

src/google/protobuf/wire_format.cc

@@ -562,7 +562,7 @@ bool WireFormat::ParseAndMergeField(
       }
 
       case FieldDescriptor::TYPE_BYTES: {
-        if (internal::cpp::EffectiveStringCType(field) == FieldOptions::CORD) {
+        if (field->cpp_string_type() == FieldDescriptor::CppStringType::kCord) {
           absl::Cord value;
           if (!WireFormatLite::ReadBytes(input, &value)) return false;
           message_reflection->SetString(message, field, value);
@@ -1005,7 +1005,7 @@ const char* WireFormat::_InternalParseAndMergeField(
     case FieldDescriptor::TYPE_BYTES: {
       int size = ReadSize(&ptr);
       if (ptr == nullptr) return nullptr;
-      if (internal::cpp::EffectiveStringCType(field) == FieldOptions::CORD) {
+      if (field->cpp_string_type() == FieldDescriptor::CppStringType::kCord) {
         absl::Cord value;
         ptr = ctx->ReadCord(ptr, size, &value);
         if (ptr == nullptr) return nullptr;
@@ -1428,7 +1428,7 @@ uint8_t* WireFormat::InternalSerializeField(const FieldDescriptor* field,
       }
 
       case FieldDescriptor::TYPE_BYTES: {
-        if (internal::cpp::EffectiveStringCType(field) == FieldOptions::CORD) {
+        if (field->cpp_string_type() == FieldDescriptor::CppStringType::kCord) {
           absl::Cord value = message_reflection->GetCord(message, field);
           target = stream->WriteString(field->number(), value, target);
           break;
@@ -1748,7 +1748,7 @@ size_t WireFormat::FieldDataOnlyByteSize(const FieldDescriptor* field,
     // instead of copying.
     case FieldDescriptor::TYPE_STRING:
     case FieldDescriptor::TYPE_BYTES: {
-      if (internal::cpp::EffectiveStringCType(field) == FieldOptions::CORD) {
+      if (field->cpp_string_type() == FieldDescriptor::CppStringType::kCord) {
         for (size_t j = 0; j < count; j++) {
           absl::Cord value = message_reflection->GetCord(message, field);
           data_size += WireFormatLite::StringSize(value);