refactor(wal_history): add [[nodiscard]] attribute to list and parse_record methods

Author: umegane

src/limestone/wal_sync/wal_history.h

@@ -39,22 +39,23 @@ class wal_history {
     explicit wal_history(boost::filesystem::path dir_path);
 
     void append(epoch_id_type epoch);
-    std::vector<record> list() const;
+    [[nodiscard]] std::vector<record> list() const;
     void check_and_recover();
 
 
 
 protected:
-    // for Unit Testing
-    void set_file_operations(std::unique_ptr<file_operations> file_ops) { file_ops_ = std::move(file_ops); }
-    void reset_file_operations() { file_ops_ = std::make_unique<real_file_operations>(); }
+    // Note: These members are protected (not private) to allow access from test subclasses.
     static constexpr std::size_t record_size = sizeof(epoch_id_type) + 16 + sizeof(std::int64_t);
-    void write_record(std::ofstream& ofs, epoch_id_type epoch, const boost::uuids::uuid& uuid, std::int64_t timestamp);
-    static record parse_record(const std::array<std::byte, record_size>& buf); 
-    std::vector<record> read_all_records(const boost::filesystem::path& file_path) const;
     static constexpr const char* file_name_ = "wal_history";
     static constexpr const char* tmp_file_name_ = "wal_history.tmp";
 
+    void set_file_operations(std::unique_ptr<file_operations> file_ops) { file_ops_ = std::move(file_ops); }
+    void reset_file_operations() { file_ops_ = std::make_unique<real_file_operations>(); }
+    void write_record(std::ofstream& ofs, epoch_id_type epoch, const boost::uuids::uuid& uuid, std::int64_t timestamp);
+    [[nodiscard]] static record parse_record(const std::array<std::byte, record_size>& buf); 
+    [[nodiscard]] std::vector<record> read_all_records(const boost::filesystem::path& file_path) const;
+
 private:
     boost::filesystem::path dir_path_;
     std::unique_ptr<file_operations> file_ops_ = std::make_unique<real_file_operations>();

test/limestone/wal_sync/wal_history_test.cpp

@@ -182,7 +182,7 @@ TEST_F(wal_history_test, read_all_records_throws_on_open_failure) {
     ofs << "dummy";
     ofs.close();
     try {
-        wh.list();
+        auto _ = wh.list();
         FAIL() << "Exception was not thrown";
     } catch (const limestone_exception& ex) {
         EXPECT_TRUE(std::string(ex.what()).find("Failed to open wal_history for read:") != std::string::npos);
@@ -201,7 +201,7 @@ TEST_F(wal_history_test, read_all_records_throws_on_exists_error) {
     auto failing_ops = std::make_unique<FailingExistsFileOps>();
     wh.set_file_operations(std::move(failing_ops));
     try {
-        wh.list();
+        auto _ = wh.list();
         FAIL() << "Exception was not thrown";
     } catch (const limestone_exception& ex) {
         EXPECT_TRUE(std::string(ex.what()).find("Failed to check existence of wal_history:") != std::string::npos);
@@ -216,7 +216,7 @@ TEST_F(wal_history_test, read_all_records_throws_on_partial_record_read) {
     ofs.put('x');
     ofs.close();
     try {
-        wh.list();
+        auto _ = wh.list();
         FAIL() << "Exception was not thrown";
     } catch (const limestone_exception& ex) {
         EXPECT_TRUE(std::string(ex.what()).find("Failed to read wal_history file: partial record read:") != std::string::npos);
@@ -234,7 +234,7 @@ TEST_F(wal_history_test, read_all_records_throws_on_stream_error) {
     auto failing_ops = std::make_unique<FailingFileOps>();
     wh.set_file_operations(std::move(failing_ops));
     try {
-        wh.list();
+        auto _ = wh.list();
         FAIL() << "Exception was not thrown";
     } catch (const limestone_exception& ex) {
         EXPECT_TRUE(std::string(ex.what()).find("Failed to read wal_history file: stream error:") != std::string::npos);