Breaking change: Upgrade return type of several string returning functions to `absl::string_view`.

This includes (but not limited to) `MessageLite::GetTypeName`, `UnknownField::length_delimited`, and
all the name functions in descriptors like `FieldDescriptor::full_name`.

Part of the changes announced in
https://protobuf.dev/news/2024-10-02/#descriptor-apis

PiperOrigin-RevId: 715013326

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

@@ -39,7 +39,7 @@ void SetCordVariables(
       "\"", absl::CEscape(descriptor->default_value_string()), "\"");
   (*variables)["default_length"] =
       absl::StrCat(descriptor->default_value_string().length());
-  (*variables)["full_name"] = descriptor->full_name();
+  (*variables)["full_name"] = std::string(descriptor->full_name());
   // For one of Cords
   (*variables)["default_variable_name"] = MakeDefaultName(descriptor);
   (*variables)["default_variable_field"] = MakeDefaultFieldName(descriptor);

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

@@ -32,8 +32,8 @@ class ServiceGenerator {
       const absl::flat_hash_map<absl::string_view, std::string>& vars,
       const Options& options)
       : descriptor_(descriptor), options_(&options), vars_(vars) {
-    vars_["classname"] = descriptor_->name();
+    vars_["classname"] = std::string(descriptor_->name());
-    vars_["full_name"] = descriptor_->full_name();
+    vars_["full_name"] = std::string(descriptor_->full_name());
   }
 
   ServiceGenerator(const ServiceGenerator&) = delete;

src/google/protobuf/compiler/csharp/csharp_field_base.cc

@@ -72,7 +72,7 @@ void FieldGeneratorBase::SetCommonFieldVariables(
   (*variables)["type_name"] = type_name();
   (*variables)["extended_type"] = GetClassName(descriptor_->containing_type());
   (*variables)["name"] = name();
-  (*variables)["descriptor_name"] = descriptor_->name();
+  (*variables)["descriptor_name"] = std::string(descriptor_->name());
   (*variables)["default_value"] = default_value();
   (*variables)["capitalized_type_name"] = capitalized_type_name();
   (*variables)["number"] = number();

src/google/protobuf/compiler/csharp/csharp_message.cc

@@ -212,7 +212,7 @@ void MessageGenerator::Generate(io::Printer* printer) {
     const OneofDescriptor* oneof = descriptor_->oneof_decl(i);
     vars["name"] = UnderscoresToCamelCase(oneof->name(), false);
     vars["property_name"] = UnderscoresToCamelCase(oneof->name(), true);
-    vars["original_name"] = oneof->name();
+    vars["original_name"] = std::string(oneof->name());
     printer->Print(vars,
                    "private object $name$_;\n"
                    "/// <summary>Enum of possible cases for the "

src/google/protobuf/compiler/java/doc_comment.cc

@@ -210,7 +210,7 @@ static void WriteDebugString(io::Printer* printer, const FieldDescriptor* field,
                              const Options options, const bool kdoc) {
   std::string field_comment = FirstLineOf(field->DebugString());
   if (options.strip_nonfunctional_codegen) {
-    field_comment = field->name();
+    field_comment = std::string(field->name());
   }
   if (kdoc) {
     printer->Print(" * `$def$`\n", "def", EscapeKdoc(field_comment));

src/google/protobuf/compiler/java/field_common.cc

@@ -16,9 +16,10 @@ namespace java {
 void SetCommonFieldVariables(
     const FieldDescriptor* descriptor, const FieldGeneratorInfo* info,
     absl::flat_hash_map<absl::string_view, std::string>* variables) {
-  (*variables)["field_name"] = descriptor->name();
+  (*variables)["field_name"] = std::string(descriptor->name());
   (*variables)["name"] = info->name;
-  (*variables)["classname"] = descriptor->containing_type()->name();
+  (*variables)["classname"] =
+      std::string(descriptor->containing_type()->name());
   (*variables)["capitalized_name"] = info->capitalized_name;
   (*variables)["disambiguated_reason"] = info->disambiguated_reason;
   (*variables)["constant_name"] = FieldConstantName(descriptor);

src/google/protobuf/compiler/java/file.cc

@@ -205,12 +205,11 @@ bool FileGenerator::Validate(std::string* error) {
   // end up overwriting the outer class with one of the inner ones.
   if (name_resolver_->HasConflictingClassName(file_, classname_,
                                               NameEquality::EXACT_EQUAL)) {
-    error->assign(file_->name());
+    *error = absl::StrCat(
-    error->append(
+        file_->name(),
         ": Cannot generate Java output because the file's outer class name, "
-        "\"");
+        "\"",
-    error->append(classname_);
+        classname_,
-    error->append(
         "\", matches the name of one of the types declared inside it.  "
         "Please either rename the type or use the java_outer_classname "
         "option to specify a different outer class name for the .proto file.");

src/google/protobuf/compiler/java/full/enum.cc

@@ -85,7 +85,7 @@ void EnumNonLiteGenerator::Generate(io::Printer* printer) {
 
   for (const EnumValueDescriptor* value : canonical_values_) {
     absl::flat_hash_map<absl::string_view, std::string> vars;
-    vars["name"] = value->name();
+    vars["name"] = std::string(value->name());
     vars["index"] = absl::StrCat(value->index());
     vars["number"] = absl::StrCat(value->number());
     WriteEnumValueDocComment(printer, value, context_->options());
@@ -124,9 +124,9 @@ void EnumNonLiteGenerator::Generate(io::Printer* printer) {
 
   for (const Alias& alias : aliases_) {
     absl::flat_hash_map<absl::string_view, std::string> vars;
-    vars["classname"] = descriptor_->name();
+    vars["classname"] = std::string(descriptor_->name());
-    vars["name"] = alias.value->name();
+    vars["name"] = std::string(alias.value->name());
-    vars["canonical_name"] = alias.canonical_value->name();
+    vars["canonical_name"] = std::string(alias.canonical_value->name());
     WriteEnumValueDocComment(printer, alias.value, context_->options());
     printer->Print(
         vars, "public static final $classname$ $name$ = $canonical_name$;\n");
@@ -135,7 +135,7 @@ void EnumNonLiteGenerator::Generate(io::Printer* printer) {
 
   for (int i = 0; i < descriptor_->value_count(); i++) {
     absl::flat_hash_map<absl::string_view, std::string> vars;
-    vars["name"] = descriptor_->value(i)->name();
+    vars["name"] = std::string(descriptor_->value(i)->name());
     vars["number"] = absl::StrCat(descriptor_->value(i)->number());
     vars["{"] = "";
     vars["}"] = "";

src/google/protobuf/compiler/java/full/message.cc

@@ -294,7 +294,7 @@ void ImmutableMessageGenerator::Generate(io::Printer* printer) {
 
   absl::flat_hash_map<absl::string_view, std::string> variables;
   variables["static"] = is_own_file ? "" : "static ";
-  variables["classname"] = descriptor_->name();
+  variables["classname"] = std::string(descriptor_->name());
   variables["extra_interfaces"] = ExtraMessageInterfaces(descriptor_);
   variables["deprecation"] =
       descriptor_->options().deprecated() ? "@java.lang.Deprecated " : "";

src/google/protobuf/compiler/java/lite/enum.cc

@@ -71,7 +71,7 @@ void EnumLiteGenerator::Generate(io::Printer* printer) {
 
   for (const EnumValueDescriptor* value : canonical_values_) {
     absl::flat_hash_map<absl::string_view, std::string> vars;
-    vars["name"] = value->name();
+    vars["name"] = std::string(value->name());
     vars["number"] = absl::StrCat(value->number());
     WriteEnumValueDocComment(printer, value, context_->options());
     if (value->options().deprecated()) {
@@ -94,9 +94,9 @@ void EnumLiteGenerator::Generate(io::Printer* printer) {
 
   for (const Alias& alias : aliases_) {
     absl::flat_hash_map<absl::string_view, std::string> vars;
-    vars["classname"] = descriptor_->name();
+    vars["classname"] = std::string(descriptor_->name());
-    vars["name"] = alias.value->name();
+    vars["name"] = std::string(alias.value->name());
-    vars["canonical_name"] = alias.canonical_value->name();
+    vars["canonical_name"] = std::string(alias.canonical_value->name());
     WriteEnumValueDocComment(printer, alias.value, context_->options());
     printer->Print(
         vars, "public static final $classname$ $name$ = $canonical_name$;\n");
@@ -105,7 +105,7 @@ void EnumLiteGenerator::Generate(io::Printer* printer) {
 
   for (int i = 0; i < descriptor_->value_count(); i++) {
     absl::flat_hash_map<absl::string_view, std::string> vars;
-    vars["name"] = descriptor_->value(i)->name();
+    vars["name"] = std::string(descriptor_->value(i)->name());
     vars["number"] = absl::StrCat(descriptor_->value(i)->number());
     vars["{"] = "";
     vars["}"] = "";

src/google/protobuf/compiler/java/lite/message.cc

@@ -149,7 +149,7 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
   absl::flat_hash_map<absl::string_view, std::string> variables = {{"{", ""},
                                                                    {"}", ""}};
   variables["static"] = is_own_file ? " " : " static ";
-  variables["classname"] = descriptor_->name();
+  variables["classname"] = std::string(descriptor_->name());
   variables["extra_interfaces"] = ExtraMessageInterfaces(descriptor_);
   variables["deprecation"] =
       descriptor_->options().deprecated() ? "@java.lang.Deprecated " : "";

src/google/protobuf/compiler/java/name_resolver.cc

@@ -142,9 +142,9 @@ std::string ClassNameResolver::GetFileDefaultImmutableClassName(
   std::string basename;
   std::string::size_type last_slash = file->name().find_last_of('/');
   if (last_slash == std::string::npos) {
-    basename = file->name();
+    basename = std::string(file->name());
   } else {
-    basename = file->name().substr(last_slash + 1);
+    basename = std::string(file->name().substr(last_slash + 1));
   }
   // foo_bar_baz.proto -> FooBarBaz
   std::string ret = UnderscoresToCamelCase(StripProto(basename), true);

src/google/protobuf/compiler/java/names.cc

@@ -86,9 +86,9 @@ std::string FieldName(const FieldDescriptor* field) {
   // of the group type.  In Java, though, we would like to retain the original
   // capitalization of the type name.
   if (internal::cpp::IsGroupLike(*field)) {
-    field_name = field->message_type()->name();
+    field_name = std::string(field->message_type()->name());
   } else {
-    field_name = field->name();
+    field_name = std::string(field->name());
   }
   if (IsForbidden(field_name)) {
     // Append a trailing "#" to indicate that the name should be decorated to
@@ -130,7 +130,7 @@ std::string FileJavaPackage(const FileDescriptor* file, bool immutable,
     result = DefaultPackage(options);
     if (!file->package().empty()) {
       if (!result.empty()) result += '.';
-      result += file->package();
+      absl::StrAppend(&result, file->package());
     }
   }
 

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

@@ -41,9 +41,9 @@ void SetCommonFieldVariables(
   std::string camel_case_name = FieldName(descriptor);
   std::string raw_field_name;
   if (internal::cpp::IsGroupLike(*descriptor)) {
-    raw_field_name = descriptor->message_type()->name();
+    raw_field_name = std::string(descriptor->message_type()->name());
   } else {
-    raw_field_name = descriptor->name();
+    raw_field_name = std::string(descriptor->name());
   }
   // The logic here has to match -[GGPBFieldDescriptor textFormatName].
   const std::string un_camel_case_name(

src/google/protobuf/compiler/python/generator.cc

@@ -562,8 +562,8 @@ void Generator::PrintResolvedFeatures() const {
 void Generator::PrintFileDescriptor() const {
   absl::flat_hash_map<absl::string_view, std::string> m;
   m["descriptor_name"] = kDescriptorKey;
-  m["name"] = file_->name();
+  m["name"] = std::string(file_->name());
-  m["package"] = file_->package();
+  m["package"] = std::string(file_->package());
   m["syntax"] = GetLegacySyntaxName(GetEdition(*file_));
   m["edition"] = Edition_Name(GetEdition(*file_));
   m["options"] = OptionsValue(proto_.options().SerializeAsString());
@@ -645,8 +645,8 @@ void Generator::PrintEnum(const EnumDescriptor& enum_descriptor,
   std::string module_level_descriptor_name =
       ModuleLevelDescriptorName(enum_descriptor);
   m["descriptor_name"] = module_level_descriptor_name;
-  m["name"] = enum_descriptor.name();
+  m["name"] = std::string(enum_descriptor.name());
-  m["full_name"] = enum_descriptor.full_name();
+  m["full_name"] = std::string(enum_descriptor.full_name());
   m["file"] = kDescriptorKey;
   const char enum_descriptor_template[] =
       "$descriptor_name$ = _descriptor.EnumDescriptor(\n"
@@ -720,7 +720,7 @@ void Generator::PrintServiceDescriptor(
     const ServiceDescriptor& descriptor) const {
   absl::flat_hash_map<absl::string_view, std::string> m;
   m["service_name"] = ModuleLevelServiceDescriptorName(descriptor);
-  m["name"] = descriptor.name();
+  m["name"] = std::string(descriptor.name());
   m["file"] = kDescriptorKey;
   printer_->Print(m, "$service_name$ = $file$.services_by_name['$name$']\n");
 }
@@ -770,8 +770,8 @@ void Generator::PrintServiceStub(const ServiceDescriptor& descriptor) const {
 void Generator::PrintDescriptor(const Descriptor& message_descriptor,
                                 const DescriptorProto& proto) const {
   absl::flat_hash_map<absl::string_view, std::string> m;
-  m["name"] = message_descriptor.name();
+  m["name"] = std::string(message_descriptor.name());
-  m["full_name"] = message_descriptor.full_name();
+  m["full_name"] = std::string(message_descriptor.full_name());
   m["file"] = kDescriptorKey;
 
   PrintNestedDescriptors(message_descriptor, proto);
@@ -836,8 +836,8 @@ void Generator::PrintDescriptor(const Descriptor& message_descriptor,
   for (int i = 0; i < message_descriptor.oneof_decl_count(); ++i) {
     const OneofDescriptor* desc = message_descriptor.oneof_decl(i);
     m.clear();
-    m["name"] = desc->name();
+    m["name"] = std::string(desc->name());
-    m["full_name"] = desc->full_name();
+    m["full_name"] = std::string(desc->full_name());
     m["index"] = absl::StrCat(desc->index());
     options_string =
         OptionsValue(proto.oneof_decl(i).options().SerializeAsString());
@@ -980,9 +980,9 @@ void Generator::FixForeignFieldsInDescriptor(
     absl::flat_hash_map<absl::string_view, std::string> m;
     const OneofDescriptor* oneof = descriptor.oneof_decl(i);
     m["descriptor_name"] = ModuleLevelDescriptorName(descriptor);
-    m["oneof_name"] = oneof->name();
+    m["oneof_name"] = std::string(oneof->name());
     for (int j = 0; j < oneof->field_count(); ++j) {
-      m["field_name"] = oneof->field(j)->name();
+      m["field_name"] = std::string(oneof->field(j)->name());
       printer_->Print(
           m,
           "$descriptor_name$.oneofs_by_name['$oneof_name$'].fields.append(\n"
@@ -998,7 +998,7 @@ void Generator::FixForeignFieldsInDescriptor(
 void Generator::AddMessageToFileDescriptor(const Descriptor& descriptor) const {
   absl::flat_hash_map<absl::string_view, std::string> m;
   m["descriptor_name"] = kDescriptorKey;
-  m["message_name"] = descriptor.name();
+  m["message_name"] = std::string(descriptor.name());
   m["message_descriptor_name"] = ModuleLevelDescriptorName(descriptor);
   const char file_descriptor_template[] =
       "$descriptor_name$.message_types_by_name['$message_name$'] = "
@@ -1010,7 +1010,7 @@ void Generator::AddServiceToFileDescriptor(
     const ServiceDescriptor& descriptor) const {
   absl::flat_hash_map<absl::string_view, std::string> m;
   m["descriptor_name"] = kDescriptorKey;
-  m["service_name"] = descriptor.name();
+  m["service_name"] = std::string(descriptor.name());
   m["service_descriptor_name"] = ModuleLevelServiceDescriptorName(descriptor);
   const char file_descriptor_template[] =
       "$descriptor_name$.services_by_name['$service_name$'] = "
@@ -1022,7 +1022,7 @@ void Generator::AddEnumToFileDescriptor(
     const EnumDescriptor& descriptor) const {
   absl::flat_hash_map<absl::string_view, std::string> m;
   m["descriptor_name"] = kDescriptorKey;
-  m["enum_name"] = descriptor.name();
+  m["enum_name"] = std::string(descriptor.name());
   m["enum_descriptor_name"] = ModuleLevelDescriptorName(descriptor);
   const char file_descriptor_template[] =
       "$descriptor_name$.enum_types_by_name['$enum_name$'] = "
@@ -1034,7 +1034,7 @@ void Generator::AddExtensionToFileDescriptor(
     const FieldDescriptor& descriptor) const {
   absl::flat_hash_map<absl::string_view, std::string> m;
   m["descriptor_name"] = kDescriptorKey;
-  m["field_name"] = descriptor.name();
+  m["field_name"] = std::string(descriptor.name());
   m["resolved_name"] = ResolveKeyword(descriptor.name());
   const char file_descriptor_template[] =
       "$descriptor_name$.extensions_by_name['$field_name$'] = "
@@ -1143,7 +1143,7 @@ void Generator::PrintEnumValueDescriptor(
   std::string options_string;
   proto.options().SerializeToString(&options_string);
   absl::flat_hash_map<absl::string_view, std::string> m;
-  m["name"] = descriptor.name();
+  m["name"] = std::string(descriptor.name());
   m["index"] = absl::StrCat(descriptor.index());
   m["number"] = absl::StrCat(descriptor.number());
   m["options"] = OptionsValue(options_string);
@@ -1161,8 +1161,8 @@ void Generator::PrintFieldDescriptor(const FieldDescriptor& field,
   std::string options_string;
   proto.options().SerializeToString(&options_string);
   absl::flat_hash_map<absl::string_view, std::string> m;
-  m["name"] = field.name();
+  m["name"] = std::string(field.name());
-  m["full_name"] = field.full_name();
+  m["full_name"] = std::string(field.full_name());
   m["index"] = absl::StrCat(field.index());
   m["number"] = absl::StrCat(field.number());
   m["type"] = absl::StrCat(field.type());
@@ -1456,7 +1456,7 @@ void Generator::FixOptionsForField(const FieldDescriptor& field,
   if (field.is_extension()) {
     if (field.extension_scope() == nullptr) {
       // Top level extensions.
-      field_name = field.name();
+      field_name = std::string(field.name());
     } else {
       field_name = FieldReferencingExpression(field.extension_scope(), field,
                                               "extensions_by_name");

src/google/protobuf/compiler/ruby/ruby_generator.cc

@@ -170,7 +170,7 @@ int GeneratePackageModules(const FileDescriptor* file, io::Printer* printer) {
                         << " 'A::B::C' and not 'A.B.C'";
     }
   } else {
-    package_name = file->package();
+    package_name = std::string(file->package());
   }
 
   // Use the appropriate delimiter

src/google/protobuf/descriptor.cc

@@ -3050,7 +3050,7 @@ void FieldDescriptor::CopyTo(FieldDescriptorProto* proto) const {
     if (!containing_type()->is_unqualified_placeholder_) {
       proto->set_extendee(".");
     }
-    proto->mutable_extendee()->append(containing_type()->full_name());
+    absl::StrAppend(proto->mutable_extendee(), containing_type()->full_name());
   }
 
   if (cpp_type() == CPPTYPE_MESSAGE) {
@@ -3063,12 +3063,12 @@ void FieldDescriptor::CopyTo(FieldDescriptorProto* proto) const {
     if (!message_type()->is_unqualified_placeholder_) {
       proto->set_type_name(".");
     }
-    proto->mutable_type_name()->append(message_type()->full_name());
+    absl::StrAppend(proto->mutable_type_name(), message_type()->full_name());
   } else if (cpp_type() == CPPTYPE_ENUM) {
     if (!enum_type()->is_unqualified_placeholder_) {
       proto->set_type_name(".");
     }
-    proto->mutable_type_name()->append(enum_type()->full_name());
+    absl::StrAppend(proto->mutable_type_name(), enum_type()->full_name());
   }
 
   if (has_default_value()) {
@@ -3152,12 +3152,12 @@ void MethodDescriptor::CopyTo(MethodDescriptorProto* proto) const {
   if (!input_type()->is_unqualified_placeholder_) {
     proto->set_input_type(".");
   }
-  proto->mutable_input_type()->append(input_type()->full_name());
+  absl::StrAppend(proto->mutable_input_type(), input_type()->full_name());
 
   if (!output_type()->is_unqualified_placeholder_) {
     proto->set_output_type(".");
   }
-  proto->mutable_output_type()->append(output_type()->full_name());
+  absl::StrAppend(proto->mutable_output_type(), output_type()->full_name());
 
   if (&options() != &MethodOptions::default_instance()) {
     *proto->mutable_options() = options();
@@ -3223,7 +3223,7 @@ bool RetrieveOptionsAssumingRightPool(
       if (field->is_extension()) {
         name = absl::StrCat("(.", field->full_name(), ")");
       } else {
-        name = field->name();
+        name = std::string(field->name());
       }
       option_entries->push_back(absl::StrCat(name, " = ", fieldval));
     }
@@ -7170,9 +7170,9 @@ void DescriptorBuilder::BuildEnumValue(const EnumValueDescriptorProto& proto,
     // scope.  Let's print an additional error to explain this.
     std::string outer_scope;
     if (parent->containing_type() == nullptr) {
-      outer_scope = file_->package();
+      outer_scope = std::string(file_->package());
     } else {
-      outer_scope = parent->containing_type()->full_name();
+      outer_scope = std::string(parent->containing_type()->full_name());
     }
 
     if (outer_scope.empty()) {

src/google/protobuf/port_def.inc

@@ -153,9 +153,7 @@ static_assert(PROTOBUF_ABSL_MIN(20230125, 3),
 #ifdef PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE
 #error PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE was previously defined
 #endif
-#if defined(PROTOBUF_TEMPORARY_ENABLE_STRING_VIEW_RETURN_TYPE)
 #define PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE 1
-#endif
 
 #ifdef PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE_TYPENAME
 #error PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE_TYPENAME was previously defined

src/google/protobuf/port_undef.inc

@@ -69,10 +69,10 @@
 #ifdef PROTOBUF_FUTURE_BREAKING_CHANGES
 #undef PROTOBUF_FUTURE_BREAKING_CHANGES
 #undef PROTOBUF_FUTURE_DESCRIPTOR_EXTENSION_DECL
-#undef PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE
 #undef PROTOBUF_FUTURE_REMOVE_CREATEMESSAGE
 #endif
 
+#undef PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE
 #undef PROTOBUF_FUTURE_STRING_VIEW_RETURN_TYPE_TYPENAME
 
 // Restore macros that may have been #undef'd in port_def.inc.

src/google/protobuf/reflection_ops.cc

@@ -365,16 +365,12 @@ static std::string SubMessagePrefix(const std::string& prefix,
                                     const FieldDescriptor* field, int index) {
   std::string result(prefix);
   if (field->is_extension()) {
-    result.append("(");
+    absl::StrAppend(&result, "(", field->full_name(), ")");
-    result.append(field->full_name());
-    result.append(")");
   } else {
-    result.append(field->name());
+    absl::StrAppend(&result, field->name());
   }
   if (index != -1) {
-    result.append("[");
+    absl::StrAppend(&result, "[", index, "]");
-    result.append(absl::StrCat(index));
-    result.append("]");
   }
   result.append(".");
   return result;