linter complaint about using a worker as a timer callback

[guystreeter]

Have you checked closed issues? https://github.com/Textualize/textual/issues?q=is%3Aissue+is%3Aclosed

yes

Please give a brief but clear explanation of the issue. If you can, include a complete working example that demonstrates the bug. Check it can run without modifications.

from textual import work
from textual.app import App
class testy(App):
    @work
    async def worky(self) -> None:
        pass
    def compose(self):
        self.set_timer(1, self.worky)

$ pyright test.py
/home/guy/gits/ttuna/test.py
  /home/guy/gits/ttuna/test.py:8:27 - error: Argument of type "() -> Worker[None]" cannot be assigned to parameter "callback" of type "TimerCallback | None" in function "set_timer"
    Type "() -> Worker[None]" cannot be assigned to type "TimerCallback | None"
      Type "() -> Worker[None]" cannot be assigned to type "() -> Awaitable[None]"
        Function return type "Worker[None]" is incompatible with type "Awaitable[None]"
          "Worker[None]" is incompatible with protocol "Awaitable[None]"
            "__await__" is not present
      Type "() -> Worker[None]" cannot be assigned to type "() -> None"
        Function return type "Worker[None]" is incompatible with type "None"
          Type cannot be assigned to type "None"
    ... (reportGeneralTypeIssues)
1 error, 0 warnings, 0 informations 

The same error is reported for set_interval as well

[willmcgugan]

The callback in set_timer is typed as returning None, but your worky method returns a Worker instance.

That might be too strict. We could maybe have it typed as returning Any.

In the meantime, set_timer(1, lambda: self.worky()) may quell the typing error.

[guystreeter]

Thanks, the linter is apparently too smart to be fooled by lambda. Passing it through an intermediate function works, though:

    @work
    async def worky(self) -> None:
        pass
    def do_worky(self) -> None:
        self.worky()
    def compose(self):
        self.set_timer(1, self.do_worky())

produces no complaint.

[github-actions]

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