Celery.task types loose type information

[sk-]

The types of Celery.task loose type information because they return a _T_Global in some cases. This is different to how shared_task is typed.

The code below shows how the type information is lost:

from typing import reveal_type

import celery

celery_app = celery.Celery()

@celery_app.task()
def task1(a: int) -> int:
    return a

@celery.shared_task()
def task2(a: int) -> int:
    return a

reveal_type(task1)
reveal_type(task2)

Mypy, pyright show these types:

tasks2.py:15: note: Revealed type is "celery.app.task.Task[Any, Any]"
tasks2.py:16: note: Revealed type is "celery.app.task.Task[[a: int], int]"

[sk-]

This seems to have been broken by #203. @sbdchd WDYT?

[sk-]

This issue is also affecting zuban, making it generate errors like:

test.py:7: error: Argument 1 has incompatible type "Callable[[int], int]"; expected "Callable[_P, _R]"  [arg-type]
Found 1 errors in 1 file (checked 1 source file)

I used the same python code above with two extra delay calls.

from typing import reveal_type

import celery

celery_app = celery.Celery()

@celery_app.task()
def task1(a: int) -> int:
    return a

@celery.shared_task()
def task2(a: int) -> int:
    return a

reveal_type(task1)
reveal_type(task2)

task1.delay(3)
task2.delay(3)

[sbdchd]

Yeah I'm fine if we revert that PR, ideally celery types are easy to drop in with existing code