Account for fields mapped by rules when checking for missed fields

The code after the early return mentioned in the previous commit assumed all fields would match by name,
which was of course true. But not anymore, so the missing check now only fails when the missing fields are also not already accounted for via a mapping

ros1_bridge/__init__.py

@@ -757,16 +757,21 @@ def determine_field_mapping(ros1_msg, ros2_msg, mapping_rules, msg_idx):
  # apply name based mapping of fields
  ros1_field_missing_in_ros2 = False
 
+ ros1_fields_not_mapped = []
  for ros1_field in ros1_spec.parsed_fields():
  for ros2_member in ros2_spec.structure.members:
  if ros1_field.name.lower() == ros2_member.name:
  # get package name and message name from ROS 1 field type
  update_ros1_field_information(ros1_field, ros1_msg.package_name)
  mapping.add_field_pair(ros1_field, ros2_member)
  break
- else:
+
+ ros1_fields_mapped_to_a_ros2_member = [field[0].name for field in mapping.fields_1_to_2.keys()]
+ if not ros1_field.name in ros1_fields_mapped_to_a_ros2_member:
  # this allows fields to exist in ROS 1 but not in ROS 2
- ros1_field_missing_in_ros2 = True
+ ros1_fields_not_mapped += [ros1_field]
+
+ ros1_field_missing_in_ros2 = any(ros1_fields_not_mapped)
 
  if ros1_field_missing_in_ros2:
  # if some fields exist in ROS 1 but not in ROS 2