fix timebox causing crash

When a modal was created with another window as its parent, the other
window was being returned, when it was the current window that we
actually wanted. This caused nextCard() to be called again when it
presented the timebox modal, leading to a stack overflow.

https://forums.ankiweb.net/t/anki-2-1-45-alpha/10061/71

qt/aqt/browser/browser.py

@@ -40,7 +40,7 @@ from aqt.undo import UndoActionsInfo
 from aqt.utils import (
     HelpPage,
     KeyboardModifiersPressed,
-    current_top_level_widget,
+    current_window,
     ensure_editor_saved,
     getTag,
     no_arg_trigger,
@@ -112,7 +112,7 @@ class Browser(QMainWindow):
     def on_operation_did_execute(
         self, changes: OpChanges, handler: Optional[object]
     ) -> None:
-        focused = current_top_level_widget() == self
+        focused = current_window() == self
         self.table.op_executed(changes, handler, focused)
         self.sidebar.op_executed(changes, handler, focused)
         if changes.editor:
@@ -135,7 +135,7 @@ class Browser(QMainWindow):
             self._update_context_actions()
 
     def on_focus_change(self, new: Optional[QWidget], old: Optional[QWidget]) -> None:
-        if current_top_level_widget() == self:
+        if current_window() == self:
             self.setUpdatesEnabled(True)
             self.table.redraw_cells()
             self.sidebar.refresh_if_needed()

qt/aqt/main.py

@@ -66,7 +66,7 @@ from aqt.utils import (
     KeyboardModifiersPressed,
     askUser,
     checkInvalidFilename,
-    current_top_level_widget,
+    current_window,
     disable_help_button,
     getFile,
     getOnlyText,
@@ -80,7 +80,6 @@ from aqt.utils import (
     showInfo,
     showWarning,
     tooltip,
-    top_level_widget,
     tr,
 )
 
@@ -725,7 +724,7 @@ class AnkiQt(QMainWindow):
         self, changes: OpChanges, handler: Optional[object]
     ) -> None:
         "Notify current screen of changes."
-        focused = current_top_level_widget() == self
+        focused = current_window() == self
         if self.state == "review":
             dirty = self.reviewer.op_executed(changes, handler, focused)
         elif self.state == "overview":
@@ -745,7 +744,7 @@ class AnkiQt(QMainWindow):
         self, new_focus: Optional[QWidget], _old: Optional[QWidget]
     ) -> None:
         "If main window has received focus, ensure current UI state is updated."
-        if new_focus and top_level_widget(new_focus) == self:
+        if new_focus and new_focus.window() == self:
             if self.state == "review":
                 self.reviewer.refresh_if_needed()
             elif self.state == "overview":

qt/aqt/utils.py

@@ -721,16 +721,9 @@ def downArrow() -> str:
     return "▾"
 
 
-def top_level_widget(widget: QWidget) -> QWidget:
-    window = None
-    while widget := widget.parentWidget():
-        window = widget
-    return window
-
-
-def current_top_level_widget() -> Optional[QWidget]:
+def current_window() -> Optional[QWidget]:
     if widget := QApplication.focusWidget():
-        return top_level_widget(widget)
+        return widget.window()
     else:
         return None