The discussion for this issue started in cupy/cupy#2029, please refer to it for all the details.

Currently, CuPy creates aliases from some NumPy C functions that use the __array_function__ dispatch. This causes an infinite loop since CuPy keeps on calling the NumPy function, and this dispatches the CuPy alias. Note that the same case may apply to any other libraries that implementation the __array_function__ protocol.

Summary of fix suggestions we have at the moment:

• Wrap all NumPy functions of the category described above on libraries that implement the __array_function__ protocol
• Use a sentinel (e.g., None) as a fallback to NumPy function, similar to the NEP proposal

@shoyer @mrocklin