Untyped decorator makes function untyped for strategies.composite decorator

[TomNicholas]

I expected this to pass mypy - am I typing this incorrectly or is hypothesis not typing the strategies.composite decorator correctly?

from __future__ import annotations

import hypothesis.strategies as st


@st.composite
def my_integers(
    draw: st.DrawFn,
) -> st.SearchStrategy[int]:
    return draw(st.integers())

error: Untyped decorator makes function "my_integers" untyped  [misc]

hypothesis==6.88.3, mypy==1.7.0

Came up in dask/dask#9374

[TomNicholas]

Actually maybe I was just supposed to type it like this instead

@st.composite
def my_integers(
    draw: st.DrawFn,
) -> int:
    return draw(st.integers())

[Zac-HD]

Yep, I think the latter is correct - although you could go a step further and

def my_integers() -> SearchStrategy[int]:
    return st.integers()

This does look a little silly, but I often see uses of @st.composite which could be an undecorated function which defines some strategies for arguments and then returns st.builds(...).

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I can't find an overload which makes typecheckers provide a more useful message, but I can add a runtime warning easily enough 🙂