K-Means widget hangs (intermittent, multiple number of clusters)

[stuart-cls]

What's wrong? The k-means widget sometimes hangs while running the multiple k fitting option.

The widget simply sits in the processing progress status, and will never recover from this state: Orange must be quit.

This happens on medium size datasets (~10k rows, 10-250 features) and larger. Clustering is generally quite fast for these datasets unless this bug happens.

Once the bug has been triggered, it persists for the user session (survives quit / restart of Orange) and most times can only be fixed with system reboot (or perhaps user logout).

I've connected a py-spy profiler to the hung application and dumped the following (slightly redacted) call trace:

hung-k-means_edited.txt

How can we reproduce the problem?

We haven't been able to create an .ows file that reliably reproduces this problem, despite quite some effort.

What's your environment?

• Operating system: Linux, happens on Debian 12, Almalinux 9, CentOS 8
• Orange version: Most recent versions, including at least 3.36.2
• How you installed Orange: both conda environment and pip in a venv