gh-112075: Use atomic exchange in Py_SETREF so updating dict pointers doesn't race #116620
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Updating the dict for an object uses
Py_SETREF
. This can race if multiple threads are attempting to do this and dec ref the original value multiple times. This uses_Py_atomic_exchange_ptr
to update the existing value and get the previous value for a dec ref.dict
objects thread-safe in--disable-gil
builds #112075