Merge pull request #4707 from Textualize/fix-prevent-default

fix prevent default

src/textual/message.py

@@ -146,4 +146,5 @@ def _bubble_to(self, widget: MessagePump) -> None:
         Args:
             widget: Target of bubble.
         """
+        self._no_default_action = False
         widget.post_message(self)

tests/test_message_pump.py

@@ -5,7 +5,7 @@
 from textual.events import Key
 from textual.message import Message
 from textual.widget import Widget
-from textual.widgets import Input
+from textual.widgets import Button, Input, Label
 
 
 class ValidWidget(Widget):
@@ -143,3 +143,28 @@ def on_input_changed(self) -> None:
         app.call_next(app.change_input)
         await pilot.pause()
         assert hits == 2
+
+
+async def test_prevent_default():
+    """Test that prevent_default doesn't apply when a message is bubbled."""
+
+    app_button_pressed = False
+
+    class MyButton(Button):
+        def _on_button_pressed(self, event: Button.Pressed) -> None:
+            event.prevent_default()
+
+    class PreventApp(App[None]):
+        def compose(self) -> ComposeResult:
+            yield MyButton("Press me")
+            yield Label("No pressure")
+
+        def on_button_pressed(self, event: Button.Pressed) -> None:
+            nonlocal app_button_pressed
+            app_button_pressed = True
+            self.query_one(Label).update("Ouch!")
+
+    app = PreventApp()
+    async with app.run_test() as pilot:
+        await pilot.click(MyButton)
+        assert app_button_pressed