Crashes ipykernel

[arslnb]

I'm trying to use vegafusion in a Rust project. I'm using tokio to spawn a ipykernel (basically just using python -m ipykernel_launcher with the right flags), from within a virtualenv.

Now in that ipykernel, I have installed altair using vegafusion as a data-transformer. It all works well, except when it comes to a particular dataset. Vegafusion simply crashes when trying to do one of: chart.to_json(format="vega") or vf.save_vega(chart, file="spec.json") with this dataset.

1. It works with vegafusion with the exact same code when not using ipykernel
2. It works without vegafusion using ipykernel

fwiw, since #506 logs internal rust logs in my setup, I can see that the last thing it logs is:

[2024-09-19T18:39:46Z DEBUG deno_runtime::worker] received module evaluate Ok(
        (),
    )
[2024-09-19T18:39:46Z DEBUG datafusion_functions_array] Overwrite existing UDF: array_to_string

Normally it goes on to show logs from the sql_optimizer, etc

You can check out the dataset here: trimmed-dataset.csv

[jonmmease]

Hi @arslnb, I don't fully follow your setup. Are you able to reproduce the crash using an ipython session from the command line, without launching from tokio? Do you see a stack trace or panic message anywhere?

[arslnb]

Seems like launching the ipykernel_launcher session with elevated permissions seems to work. It does not panic, just is non-responsive. It seems to work perfectly without vegafusion with the same setup.

[arslnb]

The only time you can see this state is when you launch an ipython session using Command and spawning a child process. There are many unknowns, like why this dataset, etc. Even with RUST_LOGS set to debug, there is no real error message, panic, etc to take a deeper look..