this function takes a raw pointer (wrapped in NonNull) and it must be an unsafe function, otherwise we can trivially violate memory safety unfortunately.

The only way to remove this requirement - the requirement of usingunsafe - would be if you have a "magical" function that can take an arbitrary pointer and say whether it's a valid, live, non-mutably aliased pointer to a tensor.

Here's how to create a dangling bad pointer:NonNull::new(1 as *mut u8 as *mut dlpark::ffi::DLManagedTensor) does this code crash if we run with this pointer? I think it would..

I agree with you.from_dlpack should be unsafe, and users should use it at their own risk.

I would say, we normally don't commit to public dependencies that are not stable (yes, not a very fair policy since ndarray itself is not so stable.), and dlpark is a public dependency here because it becomes part of our API. It could mean it takes a long time between version bumps.

Maybe we don't need to includedlpark as a dependency. We can create anArrayView usingArrayView::from_shape_ptr andManagedTensor. I can implementToTensor forArrayD indlpark with a new featurendarray. I'll do some quick experiments.

Later work, check compatibility of dlpack and ndarray strides, how they work, their domains etc.