Can't use registered strategy for typed dict

[Melevir]

Here is a reproducible example of the problem:

# test.py
from typing import TypedDict, Callable, NamedTuple

from hypothesis import given
from hypothesis.strategies import composite, register_type_strategy, builds, from_type

class SomeData(TypedDict):
    a: str
    b: int

@composite
def some_data_composite(draw: Callable):
    assert 0  # to be sure when it works

register_type_strategy(SomeData, some_data_composite())

@given(from_type(SomeData))
def test_some_data(item):
    print(item)

I'm expecting pytest test.py to fail since there is assert 0 in some_data_composite strategy.

The test passes (hypothesis==6.3.0), but if I will replace class SomeData(TypedDict) with class SomeData(NamedTuple) or class SomeData, it will fail.

This happens because the TypedDict case is the first thing that is handled in hypothesis.strategies._internal.core._from_type, much earlier, than _global_type_lookup check.

This seems a problem for me since I'm using Hypothesis with Deal and I want to set up a default strategy for my typed dictionaries.

If this bug is confirmed, I'll try to fix it.

[Zac-HD]

Yep, that's a bug! We'll be happy to accept a PR to make this less hard-coded 😊

• we'll also want to handle inheritance for TypedDicts - if resolving class SomeMoreData(SomeData):, the fields from SomeData should use whatever was registered for that type. It's OK to leave this for a future PR, of course - we're usually happy to take incremental improvements!
• tip: enabling syntax highlighting on GitHub

(I'm also happy to give hints or spoilers about how I'd fix it, if you want/get stuck. Just let me know)