Some typing errors about enforce

[kevinboulain]

Forgot this one.

Example 3

Code:

import datetime
from typing import List, NamedTuple
import enforce

class Example(NamedTuple):
    datetime: datetime.datetime

@enforce.runtime_validation
def example() -> List[Example]:
    return [Example(datetime.datetime.now())]

example()

Traceback:

Traceback (most recent call last):
  File "enforce_examples.py", line 9, in <module>
    def example() -> List[Example]:
  File ".../venv/lib/python3.6/site-packages/enforce/decorators.py", line 58, in runtime_validation
    return generate_decorated()
  File ".../venv/lib/python3.6/site-packages/enforce/decorators.py", line 158, in build_wrapper
    return decorate(wrapped, configuration, None)
  File ".../venv/lib/python3.6/site-packages/enforce/decorators.py", line 70, in decorate
    data = apply_enforcer(data, parent_root=parent_root, settings=configuration)
  File ".../venv/lib/python3.6/site-packages/enforce/enforcers.py", line 159, in apply_enforcer
    func.__enforcer__ = generate_new_enforcer(func, generic, parent_root, instance_of, settings)
  File ".../venv/lib/python3.6/site-packages/enforce/enforcers.py", line 227, in generate_new_enforcer
    validator = init_validator(hints, parent_root)
  File ".../venv/lib/python3.6/site-packages/enforce/validator.py", line 71, in init_validator
    syntax_tree = visit(root_parser)
  File ".../venv/lib/python3.6/site-packages/enforce/utils.py", line 17, in visit
    stack.append(last.send(last_result))
  File ".../venv/lib/python3.6/site-packages/enforce/parsers.py", line 54, in _parse_namedtuple
    new_node = yield nodes.NamedTupleNode(hint)
  File ".../venv/lib/python3.6/site-packages/enforce/nodes.py", line 390, in __init__
    super().__init__(runtime_validation(data_type), is_sequence=True, is_container=True, **kwargs)
  File ".../venv/lib/python3.6/site-packages/enforce/decorators.py", line 46, in runtime_validation
    return get_typed_namedtuple(configuration, data, fields, field_types)
  File "...venv/lib/python3.6/site-packages/enforce/decorators.py", line 180, in get_typed_namedtuple
    exec(new_init_template, context)
  File "<string>", line 1, in <module>
NameError: name 'datetime' is not defined

Can't remember the first time I got this one, sorry (it was with a custom type and not datetime but the error was similar).

EDIT: just remembered where I found a similar issue: when using forward references as indicated in the PEP/documentation.

Code:

import enforce

class Example:
    @classmethod
    @enforce.runtime_validation
    def create(cls, *args, **kwargs) -> 'Example':
        return cls(*args, **kwargs)

Example.create()

[RussBaz]

Right . . . I think they are separate issues but I will address them here.

1. I think I know where the problem lies but it is a bit troublesome to pinpoint exactly. Decorating logic issue due to the wrapt library special handling of callables.
2. Yeah, I have neglected generators, coroutines and other async stuff so far. Generators should be the easiest to add. PR are surely welcome, though!
3. Looks like a corner case of NamedTuple special handling (because you inherited from it). Will give it a look.
4. Forward Reference is not yet supported. I need to add some lazy evaluation to it. Tracked in #45

This is a pretty huge report. It will certainly take time to fix all of them as I am not very free at the moment. Anyway, I will see what I can do given the amount of time I have.

Thanks.

[kevinboulain]

This issue could be split into smaller ones (I can open new ones and close this one), whatever is best for you, I just batched some errors that I encountered while using enforce.

The Callable issue isn't that important: it's just less self-documenting and move the burden of checking the arguments to the callee.

For the generators/iterators/... that's what I thought when I saw the empty tests. :)

For NamedTuple inheritance, it could be nice to handle it as it seems to be the recommended way to do it.

[RussBaz]

You are right. Sigh... More work for me. Hahaha. Alright, I will try fixing some of them on the weekend.

Anyway, I would prefer to have separate issues. If you can, please split them.

Thank you.

[kevinboulain]

Cheer up, I think this is the most advanced library out there for this kind of thing :)
Keep up the good work.

I opened #46 & #47.

By the way, I'm not sure if Python is really suited/designed for strict typing so maybe you shouldn't try to implement everything. But I do really like to have the ability to 'typecheck' some important parts of the program (for me, this is one of the most annoying thing with Python: even if the ease of development is great, there are too much ways to get bitten and I think enforce allow us to have a little more confidence on some critical parts).