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Fix broken listener code in WindowScope #189208

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Merged
mattkae merged 2 commits into from
Jul 10, 2026
+194 −131
Merged

Fix broken listener code in WindowScope #189208

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3ffcf0b
Fix broken listener code in WindowScope
mattkae Jul 9, 2026
7db40dd
PR feedback from Gemini
mattkae Jul 9, 2026
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234 changes: 103 additions & 131 deletions packages/flutter/lib/src/widgets/_window.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -1889,12 +1889,35 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
///
/// {@macro flutter.widgets.windowing.experimental}
@internal
WindowScope({super.key, required this.controller, required super.child}) {
WindowScope({super.key, required this.controller, required super.child})
: _contentSize = controller.contentSize,
_title = _titleValue(controller),
_isActivated = _isActivatedValue(controller),
_isMaximized = _isMaximizedValue(controller),
_isMinimized = _isMinimizedValue(controller),
_isFullscreen = _isFullscreenValue(controller) {

@loic-sharma loic-sharma Jul 9, 2026

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Copying my message from the original PR: #189061 (comment)

This isn't a blocker for this PR though, please feel free to land this without addressing this comment.

I see that all our window widgets wrap the controller in a ListenableBuilder to ensure WindowScope rebuilds when the controller changes:

flutter/packages/flutter/lib/src/widgets/_window.dart

Lines 1584 to 1590 in 7152f2b

return ListenableBuilder(
listenable: controller,
builder: (BuildContext context, Widget? widget) => WindowScope(
controller: controller,
child: View(view: controller.rootView, child: child),
),
);

A drawback of this approach is that if an app developer - for some reason - decides to create a WindowScope manually but forgets the ListenableBuilder, that WindowScope will have stale values.

Would it make sense to instead have WindowScope create the ListenableBuilder itself? That would ensure that you cannot use WindowScope incorrectly.

@mattkae mattkae Jul 9, 2026

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Yes, although I also dislike that WindowScope has a public API to begin with, since it really has no reason to be created by someone else most of the time :)

if (!isWindowingEnabled) {
throw UnsupportedError(_kWindowingDisabledErrorMessage);
}
}

// A snapshot of the aspect values captured from [controller] at construction
// time.
//
// The window widgets rebuild this [WindowScope] with the same [controller]
// instance whenever the controller notifies its listeners. Because the
// controller is the same object across rebuilds, comparing the live
// controller against itself in [updateShouldNotify] and
// [updateShouldNotifyDependent] would never detect a change. Capturing the
// values here means the old and new widgets hold independent snapshots that
// can be compared to detect which aspects changed.
Comment thread
mattkae marked this conversation as resolved.
final Size _contentSize;
final String _title;
final bool _isActivated;
final bool _isMaximized;
final bool _isMinimized;
final bool _isFullscreen;

/// The controller associated with this window.
///
/// {@macro flutter.widgets.windowing.experimental}
Expand Down Expand Up @@ -1987,14 +2010,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
/// * [of], which returns the [BaseWindowController] associated with the window.
@internal
static String titleOf(BuildContext context) {
final BaseWindowController controller = _of(context, _WindowControllerAspect.title);
return switch (controller) {
RegularWindowController() => controller.title,
DialogWindowController() => controller.title,
TooltipWindowController() => '',
PopupWindowController() => '',
SatelliteWindowController() => controller.title,
};
return _titleValue(_of(context, _WindowControllerAspect.title));
}

/// Returns title of the nearest [WindowScope], or null if not found.
Expand All @@ -2012,13 +2028,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
return null;
}

return switch (controller) {
RegularWindowController() => controller.title,
DialogWindowController() => controller.title,
TooltipWindowController() => '',
PopupWindowController() => '',
SatelliteWindowController() => controller.title,
};
return _titleValue(controller);
}

/// Returns the activation status of the nearest [WindowScope].
Expand All @@ -2036,14 +2046,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
/// * [of], which returns the [BaseWindowController] associated with the window.
@internal
static bool isActivatedOf(BuildContext context) {
final BaseWindowController controller = _of(context, _WindowControllerAspect.activated);
return switch (controller) {
RegularWindowController() => controller.isActivated,
DialogWindowController() => controller.isActivated,
TooltipWindowController() => false,
PopupWindowController() => controller.isActivated,
SatelliteWindowController() => controller.isActivated,
};
return _isActivatedValue(_of(context, _WindowControllerAspect.activated));
}

/// Returns the activation status of the nearest [WindowScope],
Expand All @@ -2062,13 +2065,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
return null;
}

return switch (controller) {
RegularWindowController() => controller.isActivated,
DialogWindowController() => controller.isActivated,
TooltipWindowController() => false,
PopupWindowController() => controller.isActivated,
SatelliteWindowController() => controller.isActivated,
};
return _isActivatedValue(controller);
}

/// Returns the minimization status of the nearest [WindowScope].
Expand All @@ -2086,14 +2083,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
/// * [of], which returns the [BaseWindowController] associated with the window.
@internal
static bool isMinimizedOf(BuildContext context) {
final BaseWindowController controller = _of(context, _WindowControllerAspect.minimized);
return switch (controller) {
RegularWindowController() => controller.isMinimized,
DialogWindowController() => controller.isMinimized,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};
return _isMinimizedValue(_of(context, _WindowControllerAspect.minimized));
}

/// Returns the minimization status of the nearest [WindowScope],
Expand All @@ -2112,13 +2102,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
return null;
}

return switch (controller) {
RegularWindowController() => controller.isMinimized,
DialogWindowController() => controller.isMinimized,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};
return _isMinimizedValue(controller);
}

/// Returns the maximization status of the nearest [WindowScope].
Expand All @@ -2136,14 +2120,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
/// * [of], which returns the [BaseWindowController] associated with the window.
@internal
static bool isMaximizedOf(BuildContext context) {
final BaseWindowController controller = _of(context, _WindowControllerAspect.maximized);
return switch (controller) {
RegularWindowController() => controller.isMaximized,
DialogWindowController() => false,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};
return _isMaximizedValue(_of(context, _WindowControllerAspect.maximized));
}

/// Returns the maximization status of the nearest [WindowScope],
Expand All @@ -2162,13 +2139,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
return null;
}

return switch (controller) {
RegularWindowController() => controller.isMaximized,
DialogWindowController() => false,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};
return _isMaximizedValue(controller);
}

/// Returns the fullscreen status of the nearest [WindowScope].
Expand All @@ -2186,15 +2157,7 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
/// * [of], which returns the [BaseWindowController] associated with the window.
@internal
static bool isFullscreenOf(BuildContext context) {
final BaseWindowController controller = _of(context, _WindowControllerAspect.fullscreen);

return switch (controller) {
RegularWindowController() => controller.isFullscreen,
DialogWindowController() => false,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};
return _isFullscreenValue(_of(context, _WindowControllerAspect.fullscreen));
}

/// Returns the fullscreen status of the nearest [WindowScope],
Expand All @@ -2213,15 +2176,63 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
return null;
}

return switch (controller) {
RegularWindowController() => controller.isFullscreen,
DialogWindowController() => false,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};
return _isFullscreenValue(controller);
}

/// Computes the value of the [_WindowControllerAspect.title] aspect for the
/// given [controller]. Controllers that do not support titles report an empty
/// string.
static String _titleValue(BaseWindowController controller) => switch (controller) {
RegularWindowController() => controller.title,
DialogWindowController() => controller.title,
TooltipWindowController() => '',
PopupWindowController() => '',
SatelliteWindowController() => controller.title,
};

// Computes the value of the [_WindowControllerAspect.activated] aspect for the
// given [controller]. Controllers that do not support activation report false.
Comment thread
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static bool _isActivatedValue(BaseWindowController controller) => switch (controller) {
RegularWindowController() => controller.isActivated,
DialogWindowController() => controller.isActivated,
TooltipWindowController() => false,
PopupWindowController() => controller.isActivated,
SatelliteWindowController() => controller.isActivated,
};

/// Computes the value of the [_WindowControllerAspect.maximized] aspect for the
/// given [controller]. Controllers that do not support maximization report
/// false.
static bool _isMaximizedValue(BaseWindowController controller) => switch (controller) {
RegularWindowController() => controller.isMaximized,
DialogWindowController() => false,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};

/// Computes the value of the [_WindowControllerAspect.minimized] aspect for the
/// given [controller]. Controllers that do not support minimization report
/// false.
static bool _isMinimizedValue(BaseWindowController controller) => switch (controller) {
RegularWindowController() => controller.isMinimized,
DialogWindowController() => controller.isMinimized,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};

/// Computes the value of the [_WindowControllerAspect.fullscreen] aspect for
/// the given [controller]. Controllers that do not support fullscreen report
/// false.
static bool _isFullscreenValue(BaseWindowController controller) => switch (controller) {
RegularWindowController() => controller.isFullscreen,
DialogWindowController() => false,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
};

static BaseWindowController _of(BuildContext context, [_WindowControllerAspect? aspect]) {
if (!isWindowingEnabled) {
throw UnsupportedError(_kWindowingDisabledErrorMessage);
Expand Down Expand Up @@ -2265,7 +2276,15 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
/// {@macro flutter.widgets.windowing.experimental}
@internal
@override
bool updateShouldNotify(WindowScope oldWidget) => controller != oldWidget.controller;
bool updateShouldNotify(WindowScope oldWidget) {
return controller != oldWidget.controller ||
_contentSize != oldWidget._contentSize ||
_title != oldWidget._title ||
_isActivated != oldWidget._isActivated ||
_isMaximized != oldWidget._isMaximized ||
_isMinimized != oldWidget._isMinimized ||
_isFullscreen != oldWidget._isFullscreen;
}

/// {@macro flutter.widgets.windowing.experimental}
@internal
Expand All @@ -2275,59 +2294,12 @@ class WindowScope extends InheritedModel<_WindowControllerAspect> {
(Object dependency) =>
dependency is _WindowControllerAspect &&
switch (dependency) {
_WindowControllerAspect.contentSize =>
controller.contentSize != oldWidget.controller.contentSize,
_WindowControllerAspect.title => switch (controller) {
final RegularWindowController regular =>
regular.title != (oldWidget.controller as RegularWindowController).title,
final DialogWindowController dialog =>
dialog.title != (oldWidget.controller as DialogWindowController).title,
TooltipWindowController() => false,
PopupWindowController() => false,
final SatelliteWindowController satellite =>
satellite.title != (oldWidget.controller as SatelliteWindowController).title,
},
_WindowControllerAspect.activated => switch (controller) {
final RegularWindowController regular =>
regular.isActivated !=
(oldWidget.controller as RegularWindowController).isActivated,
final DialogWindowController dialog =>
dialog.isActivated != (oldWidget.controller as DialogWindowController).isActivated,
TooltipWindowController() => false,
final PopupWindowController popup =>
popup.isActivated != (oldWidget.controller as PopupWindowController).isActivated,
final SatelliteWindowController satellite =>
satellite.isActivated !=
(oldWidget.controller as SatelliteWindowController).isActivated,
},
_WindowControllerAspect.maximized => switch (controller) {
final RegularWindowController regular =>
regular.isMaximized !=
(oldWidget.controller as RegularWindowController).isMaximized,
DialogWindowController() => false,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
},
_WindowControllerAspect.minimized => switch (controller) {
final RegularWindowController regular =>
regular.isMinimized !=
(oldWidget.controller as RegularWindowController).isMinimized,
final DialogWindowController dialog =>
dialog.isMinimized != (oldWidget.controller as DialogWindowController).isMinimized,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
},
_WindowControllerAspect.fullscreen => switch (controller) {
final RegularWindowController regular =>
regular.isFullscreen !=
(oldWidget.controller as RegularWindowController).isFullscreen,
DialogWindowController() => false,
TooltipWindowController() => false,
PopupWindowController() => false,
SatelliteWindowController() => false,
},
_WindowControllerAspect.contentSize => _contentSize != oldWidget._contentSize,
_WindowControllerAspect.title => _title != oldWidget._title,
_WindowControllerAspect.activated => _isActivated != oldWidget._isActivated,
_WindowControllerAspect.maximized => _isMaximized != oldWidget._isMaximized,
_WindowControllerAspect.minimized => _isMinimized != oldWidget._isMinimized,
_WindowControllerAspect.fullscreen => _isFullscreen != oldWidget._isFullscreen,
},
);
}
Expand Down
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