Casting into to cpdef enum

Simplified code:

cpdef enum MyEnum:
    MY_VAL=2

def my_fn():
    return <MyEnum>2

I’d expect my_fn() to return MyEnum.MY_VAL, but just returns the int value.

[da-woods]

Do you have a sense of where it would make sense to add conversion code like this?

(Not Stefan but) I have a 50% written change with the conversion code in as a cdef __Pyx_Enum_{{name}}_to_py(int c_val) in CpdefEnum.pyx (and called from the PyrexTypes.CEnumType.create_to_py_utility_code function).

Agree there is likely a better way to handle accessing the right IntEnum value. Do you have thoughts on what would be the best way to approach this?

I’m not sure there’s a better way to approach this - Cython doesn’t look to have much special knowledge of the Python enum

Also guessing we can do some templating to simplify the branch logic (if that is the right way to go).

yes

[jakirkham]

I agree that this behaviour should be changed. Returning the corresponding Enum object is the expected result. In the case of an invalid enum integer value, I’d also expect an exception, probably a ValueError as shown in #2732 (comment). Cython can probably do something more efficient internally than the generic attribute lookup in (<object>MyEnum).ZERO.

Thanks Stefan 🙏

Do you have a sense of where it would make sense to add conversion code like this?

Agree there is likely a better way to handle accessing the right IntEnum value. Do you have thoughts on what would be the best way to approach this?

Also guessing we can do some templating to simplify the branch logic (if that is the right way to go).