Python 3.13+Exceptionsexception

PythonFinalizationError

built-in exceptions

An operation is blocked during interpreter finalization (3.13+).

Syntax

raise PythonFinalizationError

New in 3.13 and a subclass of RuntimeError; it fires when code attempts something forbidden while the interpreter is shutting down — starting a thread, forking, spawning a subprocess. The usual culprit is work scheduled too late: a __del__, an atexit hook, or a daemon thread still trying to finish. The cure is finishing and joining background work before exit rather than catching the error; before 3.13 the same situation surfaces as a plain RuntimeError.

Examples

try:
    raise PythonFinalizationError
except PythonFinalizationError as e:
    print(type(e).__name__)   # → PythonFinalizationError

See also

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