stream in `__dlpack__` should not be required to be integers

https://data-apis.org/array-api/latest/API_specification/array_object.html#dlpack-self-stream-none

says that stream keyword argument in __dlpack__(self, /, *, stream=None) should be an integer or None.

However, in dmlc/dlpack#57 discussion (see https://github.com/dmlc/dlpack/issues/57#issuecomment-771854478) in the case of working with SYCL, the stream may need to be a class representing an in-order sycl queue.

Can we remove the requirements for stream to be an integer ?

[rgommers]

Thanks for the explanation @oleksandr-pavlyk.

as long as it is allowed to be a Python object such that passing dpctl.SyclQueue or PyCapsule would be permitted.

Then how about a type annotation stream : Optional[Union[int, Any]] and a note like “For other device types which do have a stream, queue or other synchronization mechanism, the most appropriate type is not yet determined. E.g., for SYCL one may want to use an object containing an in-order cl::sycl::queue. This may be standardized in a future version of this API standard”.

[rgommers]

then unfortunately this runtime check is a price I have to pay, since DLPack attempts to cover all these device types.

I agree, not really a way around that. It’s better than have separate methods like:

• CPU: __dlpack__(self)
• CUDA/ROCm: __dlpack__(self, stream : Optional[int] = None)
• SYCL: __dlpack__(self, queue : TBD)

Because then you’re back to “what do I do if my library supports multiple device types”.