param:Optional[x] = None type hint behaves differently than Robot Framework

[mkorpela]

Please add the following "hacky" Optional removal to

PythonLibCore/src/robotlibcore.py

Line 232 in 9fcb620

return hints

 def _remove_optional_none_type_hints(self, type_hints, defaults):
    # If argument has None as a default, typing.get_type_hints adds
    # optional None to the information it returns. We don't want that.
    for arg in defaults:
        if defaults[arg] is None and arg in type_hints:
            type_ = type_hints[arg]
            if self._is_union(type_):
                try:
                    types = type_.__args__
                except AttributeError:
                    # Python 3.5.2's typing uses __union_params__ instead
                    # of __args__. This block can likely be safely removed
                    # when Python 3.5 support is dropped
                    types = type_.__union_params__
                if len(types) == 2 and types[1] is type(None):
                    type_hints[arg] = types[0]

https://github.com/robotframework/robotframework/blob/5dc9affd4aee31703a58ad105ed49579b1ca7067/src/robot/running/arguments/argumentparser.py#L101

[aaltat]

So if my keyword looks like this:

    def optional_none(self, arg: Optional[str] = None):
        pass

Then the types returned by PLC should look like this: {'arg': Union[str, None]}, or did I misunderstood something? Like in #66 ?

[mkorpela]

And defaults should return None

[aaltat]

Errr, need more work to understand what you mean?

[mkorpela]

So this is wanted behaviour:

suite.robot:

*** Settings ***
Library  lib.py

*** Test Cases ***
Testing
    kw  ok

Testing 2
    kw  fail

and lib.py:

from enum import Enum
from typing import Optional

penum = Enum("penum", "ok")

def kw(param: Optional[penum] = None):
    print(f"Ok? {param}")

Here robot will say:
"Testing 2 | FAIL |
ValueError: Argument 'param' got value 'fail' that cannot be converted to penum: penum does not have member 'fail'. Available: 'ok'"

But with PythonLibCore.. continuing in a bit.

[mkorpela]

from enum import Enum
from typing import Optional
from robotlibcore import DynamicCore, keyword

penum = Enum("penum", "ok")


class KwLib(object):

  @keyword
  def kw(self, param: Optional[penum] = None):
    print(f"Ok? {param}")

class lib(DynamicCore):

    def __init__(self):
       DynamicCore.__init__(self, [KwLib()])

This just passes -> that is wrong

[aaltat]

Good example, have to write test for it.

[aaltat]

Tested and this is fixed by #66