[macOS] Assertion failed: _keyUpMonitor was already created #105963
Description
There seems to be a bug in cocoa where [NSViewController viewWillAppear] gets called twice. This can happen in situation where there are multiple windows, one of them minimized.
When calling [NSWindow makeKeyAndOrderFront:] on the minimized window multiple times the viewWilAppear: handler gets called twice, despite window being already visible.
Here are both stacktraces:
makeKeyAndOrderFronton minimized window, quickly after the first one.
-[FlutterViewController viewWillAppear] (/Users/Matej/Projects/flutter/engine/src/flutter/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm:394)
-[NSViewController _sendViewWillAppear] (@-[NSViewController _sendViewWillAppear]:14)
-[NSViewController _windowWillOrderOnScreen] (@-[NSViewController _windowWillOrderOnScreen]:33)
-[NSView _windowWillOrderOnScreen] (@-[NSView _windowWillOrderOnScreen]:21)
-[NSView _windowWillOrderOnScreen] (@-[NSView _windowWillOrderOnScreen]:55)
-[NSView _windowWillOrderOnScreen] (@-[NSView _windowWillOrderOnScreen]:55)
-[NSWindow(NSWindow_Theme) _prepareToUnMinimizeFromDock:forceActivation:wantsToBeKey:] (@-[NSWindow(NSWindow_Theme) _prepareToUnMinimizeFromDock:forceActivation:wantsToBeKey:]:34)
-[NSWindow(NSWindow_Theme) _prepareToRestoreFromDock:forceActivation:wantsToBeKey:] (@-[NSWindow(NSWindow_Theme) _prepareToRestoreFromDock:forceActivation:wantsToBeKey:]:38)
-[NSWindow(NSWindow_Theme) _doRestoreComingFromDock:forceActivation:wantsToBeKey:] (@-[NSWindow(NSWindow_Theme) _doRestoreComingFromDock:forceActivation:wantsToBeKey:]:10)
-[NSWindow _reallyDoOrderWindowAboveOrBelow:relativeTo:findKey:forCounter:force:isModal:] (@-[NSWindow _reallyDoOrderWindowAboveOrBelow:relativeTo:findKey:forCounter:force:isModal:]:107)
-[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:] (@-[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:]:40)
-[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:] (@-[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:]:76)
-[NSWindow orderWindow:relativeTo:] (@-[NSWindow orderWindow:relativeTo:]:47)
-[NSWindow makeKeyAndOrderFront:] (@-[NSWindow makeKeyAndOrderFront:]:19)
- next call to
makeKeyAndOrderFront
-[FlutterViewController viewWillAppear] (/Users/Matej/Projects/flutter/engine/src/flutter/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm:394)
-[NSViewController _sendViewWillAppear] (@-[NSViewController _sendViewWillAppear]:14)
-[NSViewController _windowDidOrderOnScreen] (@-[NSViewController _windowDidOrderOnScreen]:33)
-[NSView _windowDidOrderOnScreen] (@-[NSView _windowDidOrderOnScreen]:21)
-[NSView _windowDidOrderOnScreen] (@-[NSView _windowDidOrderOnScreen]:55)
-[NSView _windowDidOrderOnScreen] (@-[NSView _windowDidOrderOnScreen]:55)
-[NSWindow _reallyDoOrderWindowAboveOrBelow:relativeTo:findKey:forCounter:force:isModal:] (@-[NSWindow _reallyDoOrderWindowAboveOrBelow:relativeTo:findKey:forCounter:force:isModal:]:462)
-[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:] (@-[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:]:40)
-[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:] (@-[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:]:76)
-[NSWindow orderWindow:relativeTo:] (@-[NSWindow orderWindow:relativeTo:]:47)
-[NSWindow makeKeyAndOrderFront:] (@-[NSWindow makeKeyAndOrderFront:]:19)
While this may be a bug in cocoa, it seems like this needs to be handled properly and not crash.