compose-stubs 0.2.0

Versioning

This library’s version numbers follow the SemVer 2.0.0 specification.

Installation

pip install compose-stubs

Usage

Like any other typing stub package, once installed it should “just work”. You might need to restart your type-checker.

Limitations

1. MyPy seems unable to handle type-checking compositions of async functions, returning false errors about types not matching. (Only affects use of acompose and sacompose.) (Pyright and Pyre don’t have this problem.)

2. Due to limitations in Python type hints, these typing stubs only cover at most 16 arguments in a single call to compose, acompose, or sacompose. This limit could be higher, but the higher the limit, the slower the type-checking.

   A simple workaround is to just use multiple compose calls to build up compositions bigger than 16 functions.

3. Due to limitations in Python type hints, there is an edge case in the type hints for sacompose (does not affect use of compose or acompose) if the return type of one function in a composition is awaitable and the next function accepts that awaitable (the most likely way for this to happen is if it accepts Any), then sacompose actually returns an async callable, but the type inference will think that it returns a sync callable.

4. Requires Python 3.10 and above (compose itself remains supported on much older versions, but the type hints need typing.ParamSpec).