App getting stuck on DescendantFocus

[BenniWi]

Hi everyone,

to be honest I'm not sure if I found a bug or if I'm doing something wrong. I checked the FAQs and the manual but could not find anything.

The bug

Using the below minimal example (stripped down from my actual programm), I'm creating multiple screens on top of each other.
Clicking the "click me" button will open a new screen. In then screen I want to push a new screen when entering the second "Input" with the text "blub1; blub2".
As soon as I focus on the Input, the new screen is pushed.
But from that moment on I can not do anything anymore, the app is basically stuck.

I'm using textual 3.5.0 (and 3.2.0) and I know it worked once with an older version (2.1.2)
The minimal example is:

from textual import on
from textual.app import App, ComposeResult
from textual.containers import Container, Grid
from textual.events import DescendantFocus
from textual.screen import ModalScreen
from textual.widgets import (
    Button,
    Input,
)


class OnFocusScreen(ModalScreen):

    def compose(self) -> ComposeResult:
        yield Grid(
            Button("A", variant="error", id="A"),
            id="dialog",
        )

    def on_button_pressed(self, event: Button.Pressed) -> None:
        self.dismiss()


class OnClickScreen(ModalScreen):

    def compose(self) -> ComposeResult:
        yield Grid(
            Input(
                id="test_input",
                value="abcd",
            ),
            Input(
                id="focus_test_input",
                value="focus me",
            ),
            id="new-entry-dialog",
        )

    @on(DescendantFocus, "#focus_test_input")
    def labels_input_focused(self) -> None:
        self.app.push_screen(OnFocusScreen())


class FocusTestApp(App):
    def compose(self) -> ComposeResult:
        with Container(id="focus_test_ui"):
            yield Button("click_me", id="clickme", variant="primary")

    @on(Button.Pressed, "#clickme")
    def pressed_new(self, event: Button.Pressed) -> None:
        self.push_screen(OnClickScreen())
        # self.push_screen(OnFocusScreen())


def main():
    FocusTestApp().run(inline=False)


if __name__ == "__main__":
    main()

Thanks a lot for your help.

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[willmcgugan]

It isn't clear to me what you are trying to achieve. It certainly doesn't seem to get stuck in any way I can see. Could you perhaps reduce that code so it shows the issue and no more?

Something to note, you should be using self.dimiss() rather than app.pop_screen generally.

[BenniWi]

Hi,
thanks for the fast response and converting it to a discussion.

I tried to shorten it a bit. The remaining code is necessary to reproduce the behaviour.
As it is right now: if I click the "click_me" button, and then click into the input with the text "focus me", the OnFocusScreen opens as expected, but I can not click the "A" button. The whole app is not responding any more.

If I open the OnFocusScreen directly from the main app instead of going through the OnClickScreen, everything works as expected. I can click the "A" button to return to the main app.

It seems the problem is only present if I open the OnFocusScreen via the OnClickScreen.

[willmcgugan]

I see the issue. It require focusing with the mouse, not keyboards as I am prone to do. #5899

[BenniWi]

Ah, ok. I didn't try that tbh. Good catch. Thanks for bringing it forward.

[willmcgugan]

If you have a moment, you might want to confirm the fix in #5900

[BenniWi]

Just commented on the PR. Problem is fixed.

Thanks a lot for the awesome fast fix.

And by the way: also thanks a lot for "textual" in total. It is really awesome.