feat(ffi): Validate the type of user-defined metadata when deserializing the new IR format. (#695)

Co-authored-by: kirkrodrigues <2454684+kirkrodrigues@users.noreply.github.com>

Author: LinZhihao-723

components/core/src/clp/ffi/ir_stream/Deserializer.hpp

@@ -44,8 +44,10 @@ class Deserializer {
      * @return A result containing the deserializer or an error code indicating the failure:
      * - std::errc::result_out_of_range if the IR stream is truncated
      * - std::errc::protocol_error if the IR stream is corrupted
-     * - std::errc::protocol_not_supported if the IR stream contains an unsupported metadata format
-     *   or uses an unsupported version
+     * - std::errc::protocol_not_supported if either:
+     *   - the IR stream contains an unsupported metadata format;
+     *   - the IR stream's version is unsupported;
+     *   - or the IR stream's user-defined metadata is not a JSON object.
      */
     [[nodiscard]] static auto create(ReaderInterface& reader, IrUnitHandler ir_unit_handler)
             -> OUTCOME_V2_NAMESPACE::std_result<Deserializer>;
@@ -168,6 +170,12 @@ auto Deserializer<IrUnitHandler>::create(ReaderInterface& reader, IrUnitHandler
         return std::errc::protocol_not_supported;
     }
 
+    if (metadata_json.contains(cProtocol::Metadata::UserDefinedMetadataKey)
+        && false == metadata_json.at(cProtocol::Metadata::UserDefinedMetadataKey).is_object())
+    {
+        return std::errc::protocol_not_supported;
+    }
+
     return Deserializer{std::move(ir_unit_handler), std::move(metadata_json)};
 }