Messages with multiple instances not loaded/parsed/visualized correctly

[maxpolzin]

Description

The "actuator_outputs" messages do not get read/visualized properly. In Foxglove Studio, when opening and reading a .ulog file, the topics panel shows one message: actuator_outputs. When visualizing one of the elements of the array actuator_outputs, e.g. actuator_outputs[4], an oscillation between two values can be observed.

Visualization of actuator_outputs[4] in Foxglove Studio:

To verify this is not a problem of the .ulog file, we can load and visualize the same ulog-file in PlotJuggler. Here we can see two messages: actuator_outputs.00 and actuator_outputs.01. When visualizing for example the 4th value of these two messages, we observe them displayed correctly.

Visualization of actuator_outputs.00[4] (red) and actuator_outputs.01[4] (blue) in PlotJuggler:

I assume this is a problem with the ulog-parser? Do you have any hints, how I can try to fix the parsing/visualization?

• Version: Foxglove Studio 2.8.0
• Platform: Ubuntu 22.04

Steps To Reproduce

Take a ulog-file, e.g. this one log_2_2024-7-3-17-44-26_nothing.zip, and plot actuator_outputs.output[4].

Expected Behavior

The proper visualization would be two lines showing actuator_outputs.00[4] and actuator_outputs.01[4] as two lines. One line around 1500 and the other one around 0.

[achim-k]

Thanks for reporting this bug and apologies for the delayed response, this fell off the radar.

The reason for this bug is that the multi_id field from the Subscription Message is currently not taken into account. #4 makes changes to the API to expose this field. We will fix this also on Foxglove side to take the multiId field into account when generating the topic names.

[achim-k]

Internal tracking issue: FG-9293