Minor refactor to avoid lifetime bound warnings on some callers.

PiperOrigin-RevId: 723052963

src/google/protobuf/generated_message_reflection.cc

@@ -1974,11 +1974,9 @@ absl::Cord Reflection::GetCord(const Message& message,
   }
 }
 
-absl::string_view Reflection::GetStringView(const Message& message,
-                                            const FieldDescriptor* field,
-                                            ScratchSpace& scratch) const {
-  USAGE_CHECK_ALL(GetStringView, SINGULAR, STRING);
-
+absl::string_view Reflection::GetStringViewImpl(const Message& message,
+                                                const FieldDescriptor* field,
+                                                ScratchSpace* scratch) const {
   if (field->is_extension()) {
     return GetExtensionSet(message).GetString(
         field->number(), internal::DefaultValueStringAsString(field));
@@ -1992,7 +1990,8 @@ absl::string_view Reflection::GetStringView(const Message& message,
       const auto& cord = schema_.InRealOneof(field)
                              ? *GetField<absl::Cord*>(message, field)
                              : GetField<absl::Cord>(message, field);
-      return scratch.CopyFromCord(cord);
+      ABSL_DCHECK(scratch);
+      return scratch->CopyFromCord(cord);
     }
     default:
       auto str = GetField<ArenaStringPtr>(message, field);
@@ -2000,6 +1999,13 @@ absl::string_view Reflection::GetStringView(const Message& message,
   }
 }
 
+absl::string_view Reflection::GetStringView(const Message& message,
+                                            const FieldDescriptor* field,
+                                            ScratchSpace& scratch) const {
+  USAGE_CHECK_ALL(GetStringView, SINGULAR, STRING);
+  return GetStringViewImpl(message, field, &scratch);
+}
+
 
 void Reflection::SetString(Message* message, const FieldDescriptor* field,
                            std::string value) const {

src/google/protobuf/message.h

@@ -987,6 +987,11 @@ class PROTOBUF_EXPORT Reflection final {
   RepeatedPtrField<T>* MutableRepeatedPtrFieldInternal(
       Message* message, const FieldDescriptor* field) const;
 
+  // REQUIRES: If the field is Cord, then `scratch != nullptr`.
+  absl::string_view GetStringViewImpl(const Message& message,
+                                      const FieldDescriptor* field,
+                                      ScratchSpace* scratch) const;
+
   // Obtain a pointer to a Repeated Field Structure and do some type checking:
   //   on field->cpp_type(),
   //   on field->field_option().ctype() (if ctype >= 0)