Improve task type hint

[pingsutw]

TL;DR

Before:

After:

Type

• Bug Fix
• Feature
• Plugin

Are all requirements met?

• Code completed
• Smoke tested
• Unit tests added
• Code documentation added
• Any pending items have an associated Issue

Complete description

^^^

Tracking Issue

NA

Follow-up issue

NA

[kumare3]

Interesting

[eapolinario]

Isn't this essentially voiding any guarantee that tools like mypy or pyright could give users?

[eapolinario]

mypy still complains about tasks invoked in workflows:

❯ cat workflows/example.py
import typing
from flytekit.core.task import task
from flytekit.core.workflow import workflow

@task
def say_hello(name: str) -> str:
    return f"hello {name}!"

@task
def greeting_length(greeting: str) -> int:
    return len(greeting)

@workflow
def wf(name: str) -> typing.Tuple[str, int]:
    greeting = say_hello(name=name)
    greeting_len = greeting_length(greeting=greeting)
    return greeting, greeting_len

❯ mypy workflows/example.py
workflows/example.py:17: error: Incompatible return value type (got "tuple[Promise | VoidPromise | tuple[Any, ...] | None, Promise | VoidPromise | tuple[Any, ...] | None]", expected "tuple[str, int]")  [return-value]
Found 1 error in 1 file (checked 1 source file)

[pingsutw]

[eapolinario]

Nevermind. I tested this by producing a wheel and installing it in a separate venv, but probably messed up on the way. Sorry for the false alarm!

[eapolinario]

This is awesome!

Should we also add a py.typed?

[wild-endeavor]

Related to #1631

[pingsutw]

Should we also add a py.typed?

I'm not sure if we have fixed all the mypy issues. Will do more testing for mypy and add it.

[eapolinario]

Should we also add a py.typed?

I'm not sure if we have fixed all the mypy issues. Will do more testing for mypy and add it.

there's at least one case where this is going to break badly: NamedTuple. But that shouldn't stop us from shipping this (i.e. we can document this limitation for the time being).