Add errors.reserve to help the compiler

liuzicheng1987 · liuzicheng1987 · commit 72d059aa91c6 · 2026-04-02T12:01:11.000+02:00
diff --git a/docs/supported_formats/cereal.md b/docs/supported_formats/cereal.md
@@ -5,8 +5,6 @@ Furthermore, when compiling reflect-cpp, you need to pass `-DREFLECTCPP_CEREAL=O
 
 Cereal is a C++ serialization library that provides multiple archive formats including binary, portable binary, JSON, and XML formats, even though we use the portable binary format.
 
-Note that on some versions of GCC, it is necessary to compile with `-Wno-stringop-overflow`, because of false positive warnings due to a known compiler bug, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110498.
-
 ## Reading and writing
 
 Suppose you have a struct like this:
diff --git a/include/rfl/parsing/NamedTupleParser.hpp b/include/rfl/parsing/NamedTupleParser.hpp
@@ -262,10 +262,8 @@ struct NamedTupleParser {
       if constexpr (is_required_field) {
         constexpr auto current_name =
             internal::nth_element_t<_i, FieldTypes...>::name();
-        std::stringstream stream;
-        stream << "Field named '" << std::string(current_name)
-               << "' not found.";
-        _errors->emplace_back(stream.str());
+        _errors->emplace_back("Field named '" + std::string(current_name) +
+                               "' not found.");
 
       } else if constexpr (!internal::has_default_val_v<NamedTupleType>) {
         if constexpr (!std::is_const_v<ValueType>) {
@@ -306,6 +304,7 @@ struct NamedTupleParser {
     auto set = std::array<bool, NamedTupleType::size()>();
     set.fill(false);
     std::vector<std::string> errors;
+    errors.reserve(size_);
     const auto reader = ViewReaderType(&_r, _view, &found, &set, &errors);
     if constexpr (_no_field_names) {
       const auto err = _r.read_array(reader, _obj_or_arr);
@@ -330,6 +329,7 @@ struct NamedTupleParser {
       const R& _r, const InputObjectOrArrayType& _obj_or_arr,
       NamedTupleType* _view) noexcept {
     std::vector<std::string> errors;
+    errors.reserve(size_);
     const auto reader = ViewReaderWithDefaultType(&_r, _view, &errors);
     if constexpr (_no_field_names) {
       const auto err = _r.read_array(reader, _obj_or_arr);
diff --git a/include/rfl/parsing/ViewReader.hpp b/include/rfl/parsing/ViewReader.hpp
@@ -74,10 +74,8 @@ class ViewReader {
       auto res = Parser<R, W, T, ProcessorsType>::read(_r, _var);
       if (!res) {
         constexpr auto name = FieldType::name();
-        std::stringstream stream;
-        stream << "Failed to parse field '" << name
-               << "': " << res.error().what();
-        _errors->emplace_back(stream.str());
+        _errors->emplace_back("Failed to parse field '" + std::string(name) +
+                               "': " + res.error().what());
         return;
       }
       if constexpr (std::is_pointer_v<OriginalType>) {
@@ -106,10 +104,9 @@ class ViewReader {
     }
     auto res = Parser<R, W, T, ProcessorsType>::read(_r, _var);
     if (!res) {
-      std::stringstream stream;
-      stream << "Failed to parse field '" << _current_name
-             << "': " << res.error().what();
-      _errors->emplace_back(stream.str());
+      _errors->emplace_back("Failed to parse field '" +
+                             std::string(_current_name) +
+                             "': " + res.error().what());
       return;
     }
     extra_fields->emplace(std::string(_current_name), std::move(*res));
@@ -142,13 +139,22 @@ class ViewReader {
           "Passing rfl::NoExtraFields to a schemaful format does not make "
           "sense, because schemaful formats cannot have extra fields.");
       if (!already_assigned) {
-        std::stringstream stream;
-        stream << "Value named '" << _current_name_or_index << "' not used.";
-        _errors->emplace_back(stream.str());
+        _errors->emplace_back("Value named '" +
+                               to_string(_current_name_or_index) +
+                               "' not used.");
       }
     }
   }
 
+  template <class T>
+  static std::string to_string(const T& _v) {
+    if constexpr (std::is_integral_v<std::remove_cvref_t<T>>) {
+      return std::to_string(_v);
+    } else {
+      return std::string(_v);
+    }
+  }
+
   template <class Target, class Source>
   static void move_to(Target* _t, Source* _s) {
     if constexpr (std::is_const_v<Target>) {
diff --git a/include/rfl/parsing/ViewReaderWithDefault.hpp b/include/rfl/parsing/ViewReaderWithDefault.hpp
@@ -60,10 +60,8 @@ class ViewReaderWithDefault {
       *_already_assigned = true;
       auto res = Parser<R, W, T, ProcessorsType>::read(_r, _var);
       if (!res) {
-        std::stringstream stream;
-        stream << "Failed to parse field '" << std::string(name)
-               << "': " << res.error().what();
-        _errors->emplace_back(stream.str());
+        _errors->emplace_back("Failed to parse field '" + std::string(name) +
+                               "': " + res.error().what());
         return;
       }
       if constexpr (std::is_pointer_v<OriginalType>) {
@@ -86,10 +84,9 @@ class ViewReaderWithDefault {
         std::remove_pointer_t<typename ExtraFieldsType::Type>>;
     auto res = Parser<R, W, T, ProcessorsType>::read(_r, _var);
     if (!res) {
-      std::stringstream stream;
-      stream << "Failed to parse field '" << _current_name
-             << "': " << res.error().what();
-      _errors->emplace_back(stream.str());
+      _errors->emplace_back("Failed to parse field '" +
+                             std::string(_current_name) +
+                             "': " + res.error().what());
       return;
     }
     extra_fields->emplace(std::string(_current_name), std::move(*res));
@@ -114,11 +111,10 @@ class ViewReaderWithDefault {
       }
     } else if constexpr (ProcessorsType::no_extra_fields_) {
       if (!already_assigned) {
-        std::stringstream stream;
-        stream << "Value named '" << std::string(_current_name)
-               << "' not used. Remove the rfl::NoExtraFields processor or add "
-                  "rfl::ExtraFields to avoid this error message.";
-        _errors->emplace_back(stream.str());
+        _errors->emplace_back(
+            "Value named '" + std::string(_current_name) +
+            "' not used. Remove the rfl::NoExtraFields processor or add "
+            "rfl::ExtraFields to avoid this error message.");
       }
     }
   }
diff --git a/include/rfl/parsing/ViewReaderWithDefaultAndStrippedFieldNames.hpp b/include/rfl/parsing/ViewReaderWithDefaultAndStrippedFieldNames.hpp
@@ -38,10 +38,8 @@ class ViewReaderWithDefaultAndStrippedFieldNames {
   /// used when the field names are stripped.
   std::optional<Error> read(const InputVarType& _var) const {
     if (i_ == size_) {
-      std::stringstream stream;
-      stream << "Expected a maximum of " << std::to_string(size_)
-             << " fields, but got at least one more.";
-      return Error(stream.str());
+      return Error("Expected a maximum of " + std::to_string(size_) +
+                   " fields, but got at least one more.");
     }
     assign_to_field_i(*r_, _var, view_, errors_, i_,
                       std::make_integer_sequence<int, size_>());
@@ -63,13 +61,10 @@ class ViewReaderWithDefaultAndStrippedFieldNames {
     if (_i == i) {
       auto res = Parser<R, W, T, ProcessorsType>::read(_r, _var);
       if (!res) {
-        std::stringstream stream;
-        stream << "Failed to parse field '" << std::string(name)
-               << "': " << res.error().what();
-        _errors->emplace_back(stream.str());
+        _errors->emplace_back("Failed to parse field '" + std::string(name) +
+                               "': " + res.error().what());
         return;
-      }
-      if constexpr (std::is_pointer_v<OriginalType>) {
+        }      if constexpr (std::is_pointer_v<OriginalType>) {
         move_to(rfl::get<i>(*_view), &(*res));
       } else {
         rfl::get<i>(*_view) = std::move(*res);
diff --git a/include/rfl/parsing/ViewReaderWithStrippedFieldNames.hpp b/include/rfl/parsing/ViewReaderWithStrippedFieldNames.hpp
@@ -39,10 +39,8 @@ class ViewReaderWithStrippedFieldNames {
   /// used when the field names are stripped.
   std::optional<Error> read(const InputVarType& _var) const {
     if (i_ == size_) {
-      std::stringstream stream;
-      stream << "Expected a maximum of " << std::to_string(size_)
-             << " fields, but got at least one more.";
-      return Error(stream.str());
+      return Error("Expected a maximum of " + std::to_string(size_) +
+                   " fields, but got at least one more.");
     }
     assign_to_field_i(*r_, _var, view_, errors_, found_, set_, i_,
                       std::make_integer_sequence<int, size_>());
@@ -66,13 +64,10 @@ class ViewReaderWithStrippedFieldNames {
       std::get<i>(*_found) = true;
       auto res = Parser<R, W, T, ProcessorsType>::read(_r, _var);
       if (!res) {
-        std::stringstream stream;
-        stream << "Failed to parse field '" << std::string(name)
-               << "': " << res.error().what();
-        _errors->emplace_back(stream.str());
+        _errors->emplace_back("Failed to parse field '" + std::string(name) +
+                               "': " + res.error().what());
         return;
-      }
-      if constexpr (std::is_pointer_v<OriginalType>) {
+        }      if constexpr (std::is_pointer_v<OriginalType>) {
         move_to(rfl::get<i>(*_view), &(*res));
       } else {
         rfl::get<i>(*_view) = std::move(*res);
diff --git a/tests/cereal/CMakeLists.txt b/tests/cereal/CMakeLists.txt
@@ -8,10 +8,6 @@ add_executable(
 )
 target_precompile_headers(reflect-cpp-cereal-tests PRIVATE [["rfl.hpp"]] <iostream> <string> <functional> <gtest/gtest.h>)
 
-if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-stringop-overflow")
-endif()
-
 target_link_libraries(reflect-cpp-cereal-tests PRIVATE reflectcpp_tests_crt)
 
 add_custom_command(TARGET reflect-cpp-cereal-tests POST_BUILD

Original file line number	Diff line number	Diff line change
`@@ -8,10 +8,6 @@ add_executable(`
`8`	`8`	`)`
`9`	`9`	`target_precompile_headers(reflect-cpp-cereal-tests PRIVATE [["rfl.hpp"]] <iostream> <string> <functional> <gtest/gtest.h>)`
`10`	`10`
`11`		`-if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")`
`12`		`- set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-stringop-overflow")`
`13`		`-endif()`
`14`		`-`
`15`	`11`	`target_link_libraries(reflect-cpp-cereal-tests PRIVATE reflectcpp_tests_crt)`
`16`	`12`
`17`	`13`	`add_custom_command(TARGET reflect-cpp-cereal-tests POST_BUILD`