fix: avoid showing closed windows (closes #3589)

closes #4924

src/logic/Applications.swift

@@ -14,11 +14,47 @@ class Applications {
     }
 
     static func manuallyRefreshAllWindows() {
+        removeZombieWindows()
+        addMissingWindows()
+    }
+
+    /// we may not receive a window-created event in some cases:
+    /// * we can't subscribe to the app
+    /// * we couldn't subscribe to the app before the window was created
+    /// * weird cases like apps launching at startup with "restaure windows"
+    /// this manually queries the system for windows, and keeps our list in-sync with the actual system
+    static func addMissingWindows() {
         for app in list {
             app.manuallyUpdateWindows()
         }
     }
 
+    /// we may not receive a window-destroyed event in some cases:
+    /// * Sequoia bug: https://github.com/lwouis/alt-tab-macos/issues/3589
+    /// * Logic Pro bug: https://github.com/lwouis/alt-tab-macos/issues/4924
+    /// this acts as a garbage-collector for windows, to keep our list in-sync with the actual system
+    static func removeZombieWindows() {
+        let wIds = Windows.list.compactMap { $0.cgWindowId }
+        guard !wIds.isEmpty else { return }
+        let values = UnsafeMutablePointer<UnsafeRawPointer?>.allocate(capacity: wIds.count)
+        for (i, id) in wIds.enumerated() {
+            values[i] = UnsafeRawPointer(bitPattern: UInt(id))
+        }
+        let rawIds = CFArrayCreate(kCFAllocatorDefault, values, wIds.count, nil)
+        let descriptions = (CGWindowListCreateDescriptionFromArray(rawIds) as? [[CFString: Any]])
+        let existingWids = descriptions?.compactMap { $0[kCGWindowNumber] } as? [CGWindowID]
+        guard let existingWids else { return }
+        let believedAlive = Set(wIds)
+        let confirmedAlive = Set(existingWids)
+        let zombies = believedAlive.subtracting(confirmedAlive)
+        for (index, window) in Windows.list.enumerated().reversed() {
+            if let wid = window.cgWindowId, zombies.contains(wid) {
+                Logger.error("----", window.title, window.application.bundleIdentifier)
+                Windows.removeWindow(index, window.application.pid)
+            }
+        }
+    }
+
     static func addRunningApplications(_ runningApps: [NSRunningApplication]) {
         runningApps.forEach {
             let bundleIdentifier = $0.bundleIdentifier

src/logic/Windows.swift

@@ -131,7 +131,21 @@ class Windows {
         }
     }
 
-    static func removeAndUpdateFocus(_ window: Window) {
+    static func removeWindow(_ index: Int, _ pid: pid_t) {
+        let window = Windows.list[index]
+        removeAndUpdateFocus(window)
+        if window.application.addWindowlessWindowIfNeeded() != nil {
+            Applications.find(pid)?.focusedWindow = nil
+        }
+        if Windows.list.count > 0 {
+            moveFocusedWindowIndexAfterWindowDestroyedInBackground(index)
+            App.app.refreshOpenUi([], .refreshUiAfterExternalEvent)
+        } else {
+            App.app.hideUi()
+        }
+    }
+
+    private static func removeAndUpdateFocus(_ window: Window) {
         let removedWindowOldFocusOrder = window.lastFocusOrder
         list.removeAll {
             if $0.lastFocusOrder == removedWindowOldFocusOrder {
@@ -245,7 +259,7 @@ class Windows {
         return targetIndex
     }
 
-    static func moveFocusedWindowIndexAfterWindowDestroyedInBackground(_ index: Int) {
+    private static func moveFocusedWindowIndexAfterWindowDestroyedInBackground(_ index: Int) {
         if index < focusedWindowIndex {
             cycleFocusedWindowIndex(-1)
         }

src/logic/events/AccessibilityEvents.swift

@@ -150,17 +150,7 @@ class AccessibilityEvents {
         let wid = try element.cgWindowId()
         DispatchQueue.main.async {
             if let index = (Windows.list.firstIndex { $0.isEqualRobust(element, wid) }) {
-                let window = Windows.list[index]
-                Windows.removeAndUpdateFocus(window)
-                if window.application.addWindowlessWindowIfNeeded() != nil {
-                    Applications.find(pid)?.focusedWindow = nil
-                }
-                if Windows.list.count > 0 {
-                    Windows.moveFocusedWindowIndexAfterWindowDestroyedInBackground(index)
-                    App.app.refreshOpenUi([], .refreshUiAfterExternalEvent)
-                } else {
-                    App.app.hideUi()
-                }
+                Windows.removeWindow(index, pid)
             }
         }
     }