This bug has to do with the get_id() function, which generates unique IDs for objects such as figures and elements. These IDs are used, for example, in custom plugins, via the get_element() function.

The problem is that I have encountered ID collisions, where two different objects have the same ID.

This breaks python visualize_tests.py --local, because the custom plugin JS code frequently (but not always!) retrieves incorrect elements, at which point execution stops because of an exception.

Interestingly, this bug happens only as of 2d757b1.

I have only reproduced this bug on Python 3.13.2.

Blocks #530.

Reproduction steps

• Use Python 3.13.2 (not sure if this is required)
• Check out 2d757b1
• Run python visualize_tests.py --local
• Open the console and read the error

Leads

IDs are calculated as follows:

objid = prefix + str(os.getpid()) + str(id(obj)) + suffix

The use of the id() function seems suspicious here. One possible lead:

Two objects with non-overlapping lifetimes may have the same id() value.