[Feature Request] Adding type checking on workflow_execute activity when a variable number of positional args exist in the callable activity

[spacether]

Is your feature request related to a problem? Please describe.

How about adding type checking on workflow_execute activity when a variable number of positional args exist in the callable activity?
Right now the args are not type checked, Sequence[Any] is allowed in

Describe the solution you'd like

Use TypedVarTupe to define *args, delete the arg input.

Additional context

I got this working with this code which would go in the workflow module

Ts = typing.TypeVarTuple("Ts")

async def execute_activity(
    activity: Union[
        typing.Callable[[*Ts], ReturnType],
        typing.Callable[[], ReturnType],
    ],
    *args: *Ts,
    task_queue: Optional[str] = None,
    result_type: Optional[Type] = None,
    schedule_to_close_timeout: Optional[timedelta] = None,
    schedule_to_start_timeout: Optional[timedelta] = None,
    start_to_close_timeout: Optional[timedelta] = None,
    heartbeat_timeout: Optional[timedelta] = None,
    retry_policy: Optional[temporalio.common.RetryPolicy] = None,
    cancellation_type: ActivityCancellationType = ActivityCancellationType.TRY_CANCEL,
    activity_id: Optional[str] = None,
    versioning_intent: Optional[VersioningIntent] = None,
) -> ReturnType:

Pros:

• this works and enforces type checking for one or more positional argument inputs

Cons:

• it only works for Python 3.11 or 3.12 and higher
• it is a breaking change and I think requires remove of the arg argument in workflow.execute_activity

See https://stackoverflow.com/questions/79476595/is-it-possible-to-type-hint-a-callable-that-takes-positional-arguments-only-usin

Other Apllications

• a fix like this would be great for signals, updates, and queries too

[cretz]

it only works for Python 3.11 or 3.12 and higher [...] it is a breaking change and I think requires remove of the arg argument in workflow.execute_activity

These limitations unfortunately mean we cannot do them. But we suggest only using single-argument items anyways as dataclasses that can get default fields added to them in a compatible manner. This is why our type-safe overloads only focus on no-param/single-param items across the codebase.