For a detailed report see #110384 (comment) (a comment by @brandtbucher on a merged PR by @markshannon ).

I am keeping notes about what I'm learning about this (though Mark said it's his).

The issue seems intermittent. I can repro it by running this command repeatedly on my Mac:

PYTHONUOPS=1 ./Programs/_testembed test_run_main_loop

Usually it passes (printing 5 lines of output); occasionally I get this error:

Py_RunMain(): sys.argv=['-c', 'arg2']
Assertion failed: (PyUnicode_CheckExact(ep->me_key)), function unicodekeys_lookup_unicode, file dictobject.c, line 938.
Abort trap: 6

I can only repro this with PYTHONUOPS=1, but it never prints any uops debug output. Could it be that the issue is in the code for checking the env var?

Linked PRs

• GH-111339: Change valid property of executors to is_valid() method #111350
• GH-111339: Move optimizer types to object.c #111430