[Core] zero-copy doesn't seem to give arrays that share memory space

[Joshuaalbert]

What happened + What you expected to happen

The simplest way to see if zero copy has been performed is to check if the memory space is shared by the original and materialised object. This is false for a simple test case. Is my test incorrect? If so, how can I verify?

Versions / Dependencies

ray 2.39

Reproduction script

import ray
import numpy as np

if __name__ == '__main__':

    ray.init(address='local')

    original_array = np.random.rand(10, 10)

    ray_ref = ray.put(original_array)

    retrieved_array = ray.get(ray_ref)

    # Verify zero-copy
    if np.shares_memory(original_array, retrieved_array):
        print("Zero-copy confirmed!")
    else:
        print("Data was copied!")

Issue Severity

High: It blocks me from completing my task.