Fix for empty objects with tagged variants (#1610)

stephenberry · Feb 11, 2025 · 8f83f3b · 8f83f3b
1 parent a116307
commit 8f83f3b
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Showing 2 changed files with 74 additions and 12 deletions.
diff --git a/include/glaze/json/read.hpp b/include/glaze/json/read.hpp
@@ -1808,6 +1808,35 @@ namespace glz
             const size_t ws_size = size_t(it - ws_start);
 
             if constexpr ((glaze_object_t<T> || reflectable<T>)&&num_members == 0 && Opts.error_on_unknown_keys) {
+               if constexpr (not tag.sv().empty()) {
+                  if (*it == '"') {
+                     ++it;
+                     GLZ_INVALID_END();
+
+                     const auto start = it;
+                     skip_string_view<Opts>(ctx, it, end);
+                     if (bool(ctx.error)) [[unlikely]]
+                        return;
+                     const sv key{start, size_t(it - start)};
+                     ++it;
+                     GLZ_INVALID_END();
+
+                     if (key == tag.sv()) {
+                        GLZ_PARSE_WS_COLON;
+
+                        read<JSON>::handle_unknown<Opts>(key, value, ctx, it, end);
+                        if (bool(ctx.error)) [[unlikely]]
+                           return;
+
+                        GLZ_SKIP_WS();
+                     }
+                     else {
+                        ctx.error = error_code::unknown_key;
+                        return;
+                     }
+                  }
+               }
+
                if (*it == '}') [[likely]] {
                   GLZ_SUB_LEVEL;
                   ++it;

diff --git a/tests/json_test/json_test.cpp b/tests/json_test/json_test.cpp
@@ -10273,44 +10273,69 @@ struct Number
    std::optional<double> maximum;
 };
 
+template <>
+struct glz::meta<Number>
+{
+   static constexpr auto value = glz::object(&Number::minimum, &Number::maximum);
+};
+
+struct Boolean {
+};
+
+template <>
+struct glz::meta<Boolean> {
+   static constexpr auto value = glz::object();
+};
+
 struct Integer
 {
    std::optional<int> minimum;
    std::optional<int> maximum;
 };
 
-struct Array;
+template <>
+struct glz::meta<Integer>
+{
+   static constexpr auto value = glz::object(&Integer::minimum, &Integer::maximum);
+};
 
 using Data = std::variant<Number, Integer>;
 
+template <>
+struct glz::meta<Data>
+{
+   static constexpr std::string_view tag = "type";
+   static constexpr auto ids = std::array{"number", "integer"};
+};
+
 struct Array
 {
    Data items;
 };
 
 template <>
-struct glz::meta<Number>
+struct glz::meta<Array>
 {
-   static constexpr auto value = glz::object(&Number::minimum, &Number::maximum);
+   static constexpr auto value = glz::object(&Array::items);
 };
 
+using Data2 = std::variant<Number, Boolean>;
+
 template <>
-struct glz::meta<Integer>
-{
-   static constexpr auto value = glz::object(&Integer::minimum, &Integer::maximum);
+struct glz::meta<Data2> {
+   static constexpr std::string_view tag = "type";
+   static constexpr auto ids = std::array{"number", "boolean"};
 };
 
-template <>
-struct glz::meta<Array>
+struct Array2
 {
-   static constexpr auto value = glz::object(&Array::items);
+   Data2 items;
 };
 
 template <>
-struct glz::meta<Data>
+struct glz::meta<Array2>
 {
-   static constexpr std::string_view tag = "type";
-   static constexpr auto ids = std::array{"number", "integer"};
+   static constexpr auto value = glz::object(&Array2::items);
 };
 
 suite tagged_variant_null_members = [] {
@@ -10321,6 +10346,14 @@ suite tagged_variant_null_members = [] {
       expect(not glz::write_json(var, s));
       expect(s == R"({"items":{"type":"number"}})") << s;
    };
+
+   "variant deduction"_test = [] {
+      Array2 var;
+      std::string str = R"({"items": { "type" : "boolean"}})";
+
+      auto pe = glz::read_json(var, str);
+      expect(not pe) << glz::format_error(pe, str);
+   };
 };
 
 int main()