Proposing a minor change which should benefit type hinting.

[matmaer]

In message_pump.py, the TYPE_CHECKING branch defines:

app = getters.app(App)

But the else branch (the actual runtime property) declares:

def app(self) -> "App[object]":

This causes a "partially unknown type" warning on every self.app access in my dev env.

The fix is a one-line change to make both branches consistent:

app = getters.app(App[object])

I believe this should have zero runtime impact.

I have a PR ready if this looks reasonable, please let me know so I can add the link to the discussion in the PR, as the template instructs me to include a link. I didn't want to open an issue as it's purely about type hinting.

[matmaer]

Sorry, forgot to include the link to the commit main...matmaer:textual:fix/message-pump-app-unknown-type

[H0R5E]

I have another problem with typing here because self.app in widgets doesn't see the actual subtype of App being used. So, roughly, if I defined a helper function in the top level app, like so:

class MyApp(App):
    def something_useful(self):
        print("SO useful")

When I try to use this function in a Widget the typing system complains because it thinks self.app is the base App class:

class MyWidget(Static)
    def make_something_useful_happen(self):
        self.app.something_useful() # <- Cannot access attribute "something_useful" for class "App[Unknown]"

[willmcgugan]

https://textual.textualize.io/api/getters/#textual.getters.app

[H0R5E]

Thank you!

[H0R5E]

Just a note to those that follow, this can be a little fiddly to avoid circular imports. I needed to use the TYPE_CHECKING guard to avoid it. For example:

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from .app import MyApp

class MyWidget(Static)
    if TYPE_CHECKING:
        app = getters.app(MyApp)

    def make_something_useful_happen(self):
        self.app.something_useful() # <- Happy pyright