Add type hints to constructors of field type classes

[KonishchevDmitry]

I've added type hints to constructors of field type classes to suggest IDE the actual type of the object and now PyCharm deduces types of all fields in model objects, even for the nested ones like model.model_list[0].nested_string which make auto-completion and refactoring to work much better.

See the screenshot:

Code I've tested it on:

from typing import List, Dict, Union, Tuple

import datetime
from decimal import Decimal

from schematics.models import Model
from schematics.types import StringType, ListType, ModelType, NumberType, IntType, FloatType, DecimalType, \
    BooleanType, DateType, DateTimeType, DictType

class TestNestedModel(Model):
    nested_string = StringType()

class TestModel(Model):
    string = StringType()
    boolean = BooleanType()
    integer = IntType()
    float = FloatType()
    number = NumberType()
    decimal = DecimalType()
    date = DateType()
    time = DateTimeType()
    dict = DictType(TestNestedModel)
    string_list = ListType(StringType())
    model = ModelType(TestNestedModel)
    model_list = ListType(ModelType(TestNestedModel))

class Bad: pass
invalid_type = Tuple[Bad, Bad, Bad, Bad, Bad, Bad, Bad, Bad, Bad, Bad, Bad, Bad, Bad]
valid_type = Tuple[str, bool, int, float, Union[int, float], Decimal, datetime.date, datetime.datetime,
                   Dict[str, TestNestedModel], List[str], TestNestedModel, List[TestNestedModel], str]

def test(valid: valid_type, invalid: invalid_type):
    pass

model = TestModel()
test_data = (
    model.string, model.boolean, model.integer, model.float, model.number, model.decimal, model.date,
    model.time, model.dict, model.string_list, model.model, model.model_list, model.model_list[0].nested_string
)
test(test_data, test_data)

[lkraider]

That's really cool. I was playing with the typing module myself for the internals, I think it merits to be included.

[lkraider]

Hi, can you rebase and remove these comments:

# ^ Override return type to suggest IDE the actual type of the object

I'll then merge it in!

[lkraider]

Can't this be represented in the doctype?

[KonishchevDmitry]

It seems that it can't. I've tried various forms like # type: (typing.Type[T], ...) -> T: it works for the model_spec argument, but breaks other arguments (**kwargs, and named parameters).

[KonishchevDmitry]

OK, removed. I added these comments just to prevent some contributors who don't know about type hinting from accidental break of my changes.

[lkraider]

Thanks for the cool patch!

[KonishchevDmitry]

Thank you!