Failure of an actor constructor does not prevent subsequent methods from working.

[robertnishihara]

If an actor constructor throws an exception, subsequent methods can still be called without problems. This deviates from standard Python behavior. For example, the following example runs to completion with no exceptions (an exception will be printed in the background for the __init__ task that failed, but it won't kill the script).

import ray

ray.init()

@ray.actor
class Foo(object):
  def __init__(self):
    raise Exception("The constructor failed!")
  def get_val(self):
    return 1

f = Foo()
ray.get(f.get_val())

[robertnishihara]

Fixed by #2843.