py/runtime: Be sure that non-intercepted thrown object is an exception.

The VM expects that, if mp_resume() returns MP_VM_RETURN_EXCEPTION, then
the returned value is an exception instance (eg to add a traceback to it).
It's possible that a value passed to a generator's throw() is not an
exception so must be explicitly checked for if the thrown value is not
intercepted by the generator.

Thanks to @jepler for finding the bug.
crypto-aes
Damien George 5 years ago
parent 3280788195
commit f50b64cab5

@ -1282,7 +1282,7 @@ mp_vm_return_kind_t mp_resume(mp_obj_t self_in, mp_obj_t send_value, mp_obj_t th
// will be propagated up. This behavior is approved by test_pep380.py
// test_delegation_of_close_to_non_generator(),
// test_delegating_throw_to_non_generator()
*ret_val = throw_value;
*ret_val = mp_make_raise_obj(throw_value);
return MP_VM_RETURN_EXCEPTION;
}
}

@ -28,3 +28,30 @@ print(g.throw(123))
g = gen()
print(next(g))
print(g.throw(ZeroDivisionError))
# this user-defined generator doesn't have a throw() method
class Iter2:
def __iter__(self):
return self
def __next__(self):
return 1
def gen2():
yield from Iter2()
# the thrown ValueError is not intercepted by the user class
g = gen2()
print(next(g))
try:
g.throw(ValueError)
except:
print('ValueError')
# the thrown 123 is not an exception so raises a TypeError
g = gen2()
print(next(g))
try:
g.throw(123)
except TypeError:
print('TypeError')

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