Plans to add zeroize::Zeroize traits to in-built PyType?

[jymchng]

For pedagogical purposes, is there a short introduction on how custom wrapper arounds PyType, e.g. Py<PyString> are dropped? My intent is to explore the possibility of having the trait Zeroize from zeroize crate implemented on custom #[pyclass].

[davidhewitt]

These are non-null pointers to Python objects, dropping them just decreases the reference count by one. If you don't have the GIL held when drop occurs, PyO3 will remember the reference to decrease later on next GIL acquisition.

If you want to zero-out the pointer I think you'd want Option<Py<PyString>>.

[jymchng]

Thank you for your reply.

By using Option<Py<PyString>>, do you mean if I want to 'zero' out the value of type PyString at the end of its usage, e.g. as a parameter to a function call etc, I can simply set the value of the Option to its None variant?

If it is used as a parameter of type PyString to a rust function call, just before the function returns, how would I be able to set it to Option<Py<PyString>>::None if it is not of type Option in the function signature?

[davidhewitt]

Yes, you could zero out by setting to the None variant.

You wouldn't be able to do this when the function signature is not optional. It's not clear to me what use case you're trying to solve by asking for that?