Keyword arguments should be keyword only arguments in the Ray API

[robertnishihara]

For example, I would suggest changing

def wait(object_ids, num_returns=1, timeout=None):

to

def wait(object_ids, *, num_returns=1, timeout=None):

This prevents users from calling ray.wait(object_ids, 1) and prevents things from breaking if we reorder keyword arguments later or add new keyword arguments.

For ray.init(), I think all arguments should be keyword only. Same with the rest of the API.

Any reason not to do this? Other than breaking existing cases that don't specify the keyword?

[simon-mo]

I'm not against it. However, this break existing user code and we should only do in next major or minor release. That will be 0.9.0 or even 1.0

To see existing usage:
https://github.com/search?l=Python&q=%22ray.wait%22&type=Code

[ericl]

IMO this is a minor issue, not worth breaking users for. There should be a very high bar for any breaking change on a commonly used API.