As a reminder, in case you didn't consider it, some code in your exec string might be run after the exec has finished, due to garbage collection.
d = {"__builtins__": {"print": print}}
exec("""
def delay_until_gc():
try:
try:
yield 1
finally:
print((1).__class__.__bases__[0].__subclasses__()[:3])
except:
raise
it = delay_until_gc()
it.__next__()
""", d, d)
del d
print("Finished exec.")
The output for this on my system is Finished exec.
[<class 'type'>, <class 'async_generator'>, <class 'bytearray_iterator'>]
which means you'll need to ensure those dictionaries are cleared and garbage collected before you can clear your toybox state, something like: import gc
toybox(1)
exec(..., d, d)
del d
gc.collect()
toybox(0)
The "del" is not good enough due to the cyclical reference as the iterator function's globals contain the active iterator.If you allow any mutable object into the globals or locals dictionary, such that the exec'ed code can attach something to it, then you can't even use gc.collect() to ensure the exec'ed code can no longer be executed.
