Adding enum to JSON schema for variants (#1447)

Author: stephenberry

include/glaze/json/schema.hpp

@@ -462,14 +462,21 @@ namespace glz
                (*s.type).emplace_back("null");
             }
             s.oneOf = std::vector<schematic>(N);
+            if (not tag_v<T>.empty()) {
+               if (not s.properties) {
+                  s.properties = std::map<std::string_view, schema, std::less<>>{}; // allocate
+               }
+               //(*s.properties)[tag_v<T>].type = "string";
+               (*s.properties)[tag_v<T>].enumeration = ids_v<T>;
+            }
 
             for_each<N>([&](auto I) {
                using V = std::decay_t<std::variant_alternative_t<I, T>>;
                auto& schema_val = (*s.oneOf)[I];
                to_json_schema<V>::template op<Opts>(schema_val, defs);
-               if constexpr ((glaze_object_t<V> || reflectable<V>)&&!tag_v<T>.empty()) {
-                  if (!schema_val.required) {
-                     schema_val.required = std::vector<sv>{};
+               if constexpr ((glaze_object_t<V> || reflectable<V>)&& not tag_v<T>.empty()) {
+                  if (not schema_val.required) {
+                     schema_val.required = std::vector<sv>{}; // allocate
                   }
                   schema_val.required->emplace_back(tag_v<T>);
                   auto& tag = (*schema_val.properties)[tag_v<T>];

tests/json_test/json_test.cpp

@@ -3335,7 +3335,7 @@ suite tagged_variant_tests = [] {
       auto s = glz::write_json_schema<tagged_variant>().value_or("error");
       expect(
          s ==
-         R"({"type":["object"],"$defs":{"int32_t":{"type":["integer"],"minimum":-2147483648,"maximum":2147483647},"std::map<std::string,int32_t>":{"type":["object"],"additionalProperties":{"$ref":"#/$defs/int32_t"}},"std::string":{"type":["string"]}},"oneOf":[{"type":["object"],"properties":{"action":{"const":"PUT"},"data":{"$ref":"#/$defs/std::map<std::string,int32_t>"}},"additionalProperties":false,"required":["action"]},{"type":["object"],"properties":{"action":{"const":"DELETE"},"data":{"$ref":"#/$defs/std::string"}},"additionalProperties":false,"required":["action"]}]})")
+         R"({"type":["object"],"properties":{"action":{"enum":["PUT","DELETE"]}},"$defs":{"int32_t":{"type":["integer"],"minimum":-2147483648,"maximum":2147483647},"std::map<std::string,int32_t>":{"type":["object"],"additionalProperties":{"$ref":"#/$defs/int32_t"}},"std::string":{"type":["string"]}},"oneOf":[{"type":["object"],"properties":{"action":{"const":"PUT"},"data":{"$ref":"#/$defs/std::map<std::string,int32_t>"}},"additionalProperties":false,"required":["action"]},{"type":["object"],"properties":{"action":{"const":"DELETE"},"data":{"$ref":"#/$defs/std::string"}},"additionalProperties":false,"required":["action"]}]})")
          << s;
    };
 
@@ -3370,7 +3370,7 @@ suite tagged_variant_tests = [] {
       const auto schema = glz::write_json_schema<std::shared_ptr<tagged_variant2>>().value_or("error");
       expect(
          schema ==
-         R"({"type":["object","null"],"$defs":{"int32_t":{"type":["integer"],"minimum":-2147483648,"maximum":2147483647},"std::map<std::string,int32_t>":{"type":["object"],"additionalProperties":{"$ref":"#/$defs/int32_t"}},"std::string":{"type":["string"]}},"oneOf":[{"type":["object"],"properties":{"data":{"$ref":"#/$defs/std::map<std::string,int32_t>"},"type":{"const":"put_action"}},"additionalProperties":false,"required":["type"]},{"type":["object"],"properties":{"data":{"$ref":"#/$defs/std::string"},"type":{"const":"delete_action"}},"additionalProperties":false,"required":["type"]},{"type":["null"],"const":null}]})")
+         R"({"type":["object","null"],"properties":{"type":{"enum":["put_action","delete_action","std::monostate"]}},"$defs":{"int32_t":{"type":["integer"],"minimum":-2147483648,"maximum":2147483647},"std::map<std::string,int32_t>":{"type":["object"],"additionalProperties":{"$ref":"#/$defs/int32_t"}},"std::string":{"type":["string"]}},"oneOf":[{"type":["object"],"properties":{"data":{"$ref":"#/$defs/std::map<std::string,int32_t>"},"type":{"const":"put_action"}},"additionalProperties":false,"required":["type"]},{"type":["object"],"properties":{"data":{"$ref":"#/$defs/std::string"},"type":{"const":"delete_action"}},"additionalProperties":false,"required":["type"]},{"type":["null"],"const":null}]})")
          << schema;
    };
 };
@@ -6864,7 +6864,7 @@ suite empty_variant_objects = [] {
       const auto s = glz::write_json_schema<var_schema>().value_or("error");
       expect(
          s ==
-         R"({"type":["object"],"properties":{"$schema":{"$ref":"#/$defs/std::string"},"variant":{"$ref":"#/$defs/vari"}},"additionalProperties":false,"$defs":{"std::string":{"type":["string"]},"vari":{"type":["object"],"oneOf":[{"type":["object"],"properties":{"type":{"const":"varx"}},"additionalProperties":false,"required":["type"]},{"type":["object"],"properties":{"type":{"const":"vary"}},"additionalProperties":false,"required":["type"]}]}}})")
+         R"({"type":["object"],"properties":{"$schema":{"$ref":"#/$defs/std::string"},"variant":{"$ref":"#/$defs/vari"}},"additionalProperties":false,"$defs":{"std::string":{"type":["string"]},"vari":{"type":["object"],"properties":{"type":{"enum":["varx","vary"]}},"oneOf":[{"type":["object"],"properties":{"type":{"const":"varx"}},"additionalProperties":false,"required":["type"]},{"type":["object"],"properties":{"type":{"const":"vary"}},"additionalProperties":false,"required":["type"]}]}}})")
          << s;
    };
 };