Return error on invalid YAML fields

dynmsg/include/dynmsg/msg_parser.hpp

@@ -34,6 +34,8 @@ namespace c
  * representation for the given ROS message.
  *
  * It is an error for the YAML representation to contain a field that is not in the ROS message.
+ * A std::runtime_error exception will be thrown in this case.
+ *
  * It is not an error for a field of the ROS message to not be specified in the YAML
  * representation; that field will be left uninitialised.
  */

dynmsg/src/msg_parser_c.cpp

@@ -15,6 +15,7 @@
 #include <yaml-cpp/yaml.h>
 
 #include <string>
+#include <unordered_set>
 
 #include "rosidl_runtime_c/string.h"
 #include "rosidl_runtime_c/string_functions.h"
@@ -413,12 +414,23 @@ void yaml_to_rosmsg_impl(
   const TypeInfo * typeinfo,
   uint8_t * buffer)
 {
+  // Put all the YAML node keys into a set. We'll be removing the keys from the set as they are parsed. If at the end
+  // there are some keys left in the set, it means the YAML has extra fields that don't belong to the message, and an
+  // exception will be thrown.
+  std::unordered_set<std::string> yaml_keys;
+  for (const auto& elem : root)
+  {
+    yaml_keys.insert(elem.first.as<std::string>());
+  }
+
+
   for (uint32_t i = 0; i < typeinfo->member_count_; i++) {
     const auto & member = typeinfo->members_[i];
 
     if (!root[member.name_]) {
       continue;
     }
+    yaml_keys.erase(member.name_);
 
     switch (member.type_id_) {
       case rosidl_typesupport_introspection_c__ROS_TYPE_FLOAT:
@@ -480,6 +492,16 @@ void yaml_to_rosmsg_impl(
         throw std::runtime_error("unknown type");
     }
   }
+  if (!yaml_keys.empty()) {
+    std::stringstream error_message;
+    error_message << "Found unknown fields in the YAML not corresponding to a " << typeinfo->message_namespace_ << "/"
+                  << typeinfo->message_name_ << " message:";
+    for (const std::string& key : yaml_keys)
+    {
+      error_message << " " << key << std::endl;
+    }
+    throw std::runtime_error(error_message.str());
+  }
 }
 
 }  // namespace impl

dynmsg/src/msg_parser_cpp.cpp

@@ -18,6 +18,7 @@
 #include <iostream>
 #include <string>
 #include <vector>
+#include <unordered_set>
 
 #include "rosidl_runtime_c/string.h"
 #include "rosidl_runtime_c/string_functions.h"
@@ -502,6 +503,15 @@ void yaml_to_rosmsg_impl(
   const TypeInfo_Cpp * typeinfo,
   uint8_t * buffer)
 {
+  // Put all the YAML node keys into a set. We'll be removing the keys from the set as they are
+  // parsed. If at the end there are some keys left in the set, it means the YAML has extra fields
+  // that don't belong to the message, and an exception will be thrown.
+  std::unordered_set<std::string> yaml_keys;
+  for (const auto& elem : root)
+  {
+    yaml_keys.insert(elem.first.as<std::string>());
+  }
+
   DYNMSG_DEBUG(std::cout << "DEBUG: yaml_to_rosmsg_impl" << std::endl);
   DYNMSG_DEBUG(
     std::cout << "DEBUG: type_info message_namespace_: " <<
@@ -514,6 +524,7 @@ void yaml_to_rosmsg_impl(
     if (!root[member.name_]) {
       continue;
     }
+    yaml_keys.erase(member.name_);
 
     switch (member.type_id_) {
       case rosidl_typesupport_introspection_cpp::ROS_TYPE_FLOAT:
@@ -575,6 +586,16 @@ void yaml_to_rosmsg_impl(
         throw std::runtime_error("unknown type");
     }
   }
+  if (!yaml_keys.empty()) {
+    std::stringstream error_message;
+    error_message << "Found unknown fields in the YAML not corresponding to a " << typeinfo->message_namespace_ << "/"
+                  << typeinfo->message_name_ << " message:";
+    for (const std::string& key : yaml_keys)
+    {
+      error_message << " " << key << std::endl;
+    }
+    throw std::runtime_error(error_message.str());
+  }
 }
 
 }  // namespace impl

dynmsg_demo/test/msg_parser_test.cpp

@@ -126,6 +126,16 @@ TEST(MsgParser, String) {
   dynmsg::c::ros_message_destroy(&generic_msg);
 }
 
+TEST(MsgParser, StringInvalidFieldCpp) {
+  EXPECT_ANY_THROW(dynmsg::cpp::yaml_to_rosmsg(
+    InterfaceTypeName{"std_msgs", "String"}, "{ invalid_field: hello }"));
+}
+
+TEST(MsgParser, StringInvalidFieldC) {
+  EXPECT_ANY_THROW(dynmsg::c::yaml_to_rosmsg(
+    InterfaceTypeName{"std_msgs", "String"}, "{ invalid_field: hello }"));
+}
+
 TEST(MsgParser, WideString) {
   auto generic_msg = dynmsg::c::yaml_to_rosmsg(
     InterfaceTypeName{"dynmsg_msgs", "WideString"},