From 47a2a3332bab8c50315143b9f37d5163d8929823 Mon Sep 17 00:00:00 2001
From: ToruNiina <niina.toru.68u@gmail.com>
Date: Sun, 27 Jun 2021 18:56:33 +0900
Subject: [PATCH] fix: use empty quoted string for empty key

---
 toml/serializer.hpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/toml/serializer.hpp b/toml/serializer.hpp
index 3012e44..4881c3d 100644
--- a/toml/serializer.hpp
+++ b/toml/serializer.hpp
@@ -29,6 +29,11 @@ template<typename charT, typename traits, typename Alloc>
 std::basic_string<charT, traits, Alloc>
 format_key(const std::basic_string<charT, traits, Alloc>& k)
 {
+    if(k.empty())
+    {
+        return std::string("\"\"");
+    }
+
     // check the key can be a bare (unquoted) key
     detail::location loc(k, std::vector<char>(k.begin(), k.end()));
     detail::lex_unquoted_key::invoke(loc);
@@ -61,9 +66,12 @@ template<typename charT, typename traits, typename Alloc>
 std::basic_string<charT, traits, Alloc>
 format_keys(const std::vector<std::basic_string<charT, traits, Alloc>>& keys)
 {
-    std::basic_string<charT, traits, Alloc> serialized;
-    if(keys.empty()) {return serialized;}
+    if(keys.empty())
+    {
+        return std::string("\"\"");
+    }
 
+    std::basic_string<charT, traits, Alloc> serialized;
     for(const auto& ky : keys)
     {
         serialized += format_key(ky);