The plugin [DataLoad ROS bags] thrown the following exception: Variant::extract -> wrong type

[yvonl]

Hi,

I have a custom ROS message VisualizationData and a bagfile containing built-in ROS messages (like std_msgs/Bool, sensor_msgs/Imu, ...) and others custom ROS messages (including VisualizationData). When I load the bagfile, if I select the topic with Datatype VisualizationData, plotjuggler fails with error:

I don't have this issue with the others custom ROS messages.

OS: Ubuntu 20.04
Plotjuggler: from snap, PlotJuggler-3 3.0.7

VisualizationData is a composition of built-in ROS type/fixed-length and variable-length array and custom ROS messages :

VisualizationData.msg

Header header

int64 image_counter
bool zero_velocity_update

int8[] camera_id_array
FrameInfo[] frames

FrameInfo.msg

Point2D[] candidates
Landmark[] landmarks
LandmarkUncertainty[] landmark_uncertainties
NewLandmark[] new_landmarks
PatchInfo[] patches

float64 roll
float64 pitch

Point2D.msg

float32 x
float32 y

Landmark.msg

uint8 LANDMARK_FINAL = 0
uint8 LANDMARK_SURROUNDING_GOOD = 1
uint8 LANDMARK_SURROUNDING_BAD = 2
uint8 LANDMARK_NOT_CONVERGED = 3
uint8 LANDMARK_INTENSITY_ERROR = 4

uint8 status
Point2D point

LandmarkUncertainty.msg

Point2D point
uint32 number

float64 sigma1
float64 sigma2
float64 sigma_angle

NewLandmark.msg

uint8 NEW_LANDMARK_CANDIDATE = 0
uint8 NEW_LANDMARK_CONVERGED_VALID = 1
uint8 NEW_LANDMARK_CONVERGED_REJECTED = 2
uint8 NEW_LANDMARK_NOT_CONVERGED = 3

uint8 status
Point2D point
uint32 number

PatchInfo.msg

uint8 PATCH_SUCCESS = 0
uint8 PATCH_NOT_IN_FRAME = 1
uint8 PATCH_OUTLIER = 2
uint8 PATCH_NOT_CONVERGED = 3
uint8 PATCH_TOO_LARGE_INTENSITY_ERROR = 4

uint8 status
Point2D point
Point2D[4] corners
float64 data

I tracked down the issue to ros1_parser.cpp: IntrospectionParser::parseMessage and the functions raising the exception to variant.hpp: Variant::extract. But I don't know why it fails to parse the message, given its definition.

Any idea what may be causing this?

[facontidavide]

can you give me a rosbag to replicate the error?

[yvonl]

Yes, of course. With this bagfile visualizationData-wrong_type.zip you should be able to reproduce the error.