Merge nucleic/keen-yarn-wren-n8iw into dev

Sources/NucleicApp/ToolbarGlassKeeper.swift

@@ -14,11 +14,19 @@ import AppKit
 /// frame a pixel and immediately back. The two `setFrame` calls coalesce within one
 /// runloop pass, so there's no visible jump, but the toolbar re-composites its glass.
 ///
-/// The nudge is debounced until the window is geometrically stable, and any resize in
-/// flight (a drag-resize or the animation of a double-click *zoom*) defers it. That
-/// matters because the non-animated `setFrame` would otherwise cancel a running zoom
-/// and snap the window back to its pre-zoom size — and a real resize is itself the
-/// relayout we're faking, so nudging during one is redundant anyway.
+/// The nudge is debounced until the window is geometrically stable. That matters
+/// because the non-animated `setFrame` would otherwise cancel a running zoom (or
+/// drag-resize) and snap the window back to its pre-zoom size — a visible stutter
+/// followed by a revert. A real resize is itself the relayout we're faking, so nudging
+/// during one is redundant anyway.
+///
+/// We can't trust resize *notifications* to tell us when a zoom is in flight — the
+/// animation of a double-click zoom doesn't reliably post `didResizeNotification` for
+/// every intermediate frame, so a notification-only debounce can still fire mid-zoom.
+/// Instead we watch the window's frame *value*: an in-flight zoom is, by definition, a
+/// frame that's still moving. Before nudging we require two consecutive samples (one
+/// debounce interval apart) to be identical; while the frame keeps changing we keep
+/// deferring. This catches any animation regardless of whether it emits notifications.
 struct ToolbarGlassKeeper: NSViewRepresentable {
     func makeNSView(context: Context) -> NSView {
         let view = NSView(frame: .zero)
@@ -45,6 +53,11 @@ struct ToolbarGlassKeeper: NSViewRepresentable {
         private var repairPending = false
         /// The debounced apply, cancelled/rescheduled while frames are still in flight.
         private var settleWorkItem: DispatchWorkItem?
+        /// The window frame seen at the previous settle. The nudge only fires once two
+        /// consecutive samples match — i.e. the frame has stopped moving — so an
+        /// animating zoom (whose frame is still changing) keeps deferring instead of
+        /// being cancelled by our `setFrame`.
+        private var lastSampledFrame: CGRect?
 
         /// Idempotent: registers once for the window's reveal / app-reactivation events.
         func attach(to window: NSWindow?) {
@@ -64,12 +77,14 @@ struct ToolbarGlassKeeper: NSViewRepresentable {
                     forName: NSApplication.didBecomeActiveNotification,
                     object: nil, queue: .main
                 ) { [weak self] _ in MainActor.assumeIsolated { self?.requestRepair() } },
-                // A resize — a drag-resize or, crucially, each step of a double-click
-                // *zoom* animation — is itself the relayout that cures the glass, so the
-                // nudge is redundant during one and, worse, its non-animated `setFrame`
-                // would cancel an in-flight zoom and snap the window back to its pre-zoom
-                // size. So a resize only defers an already-pending nudge until the frame
-                // settles; it never starts one.
+                // A resize — a drag-resize or a step of a double-click *zoom* — is itself
+                // the relayout that cures the glass, so the nudge is redundant during one
+                // and, worse, its non-animated `setFrame` would cancel an in-flight zoom
+                // and snap the window back to its pre-zoom size. When one of these
+                // notifications does fire it pushes an already-pending nudge past the
+                // resize; it never starts one. (The frame-stability check in
+                // `applyRepairIfPending` is the real guard — a zoom animation doesn't
+                // reliably post this for every frame.)
                 center.addObserver(
                     forName: NSWindow.didResizeNotification,
                     object: window, queue: .main
@@ -77,9 +92,12 @@ struct ToolbarGlassKeeper: NSViewRepresentable {
             ]
         }
 
-        /// Reveal / reactivation: mark a nudge wanted and (re)arm the debounce.
+        /// Reveal / reactivation: mark a nudge wanted and (re)arm the debounce. Seed the
+        /// frame baseline with the current frame so a still window nudges on the first
+        /// settle, while one caught mid-animation defers until its frame stops moving.
         private func requestRepair() {
             repairPending = true
+            lastSampledFrame = window?.frame
             scheduleSettle()
         }
 
@@ -96,8 +114,9 @@ struct ToolbarGlassKeeper: NSViewRepresentable {
                 MainActor.assumeIsolated { self?.applyRepairIfPending() }
             }
             settleWorkItem = work
-            // Long enough to bridge the ~16ms gaps between an animated zoom's resize
-            // steps, so a running zoom keeps re-deferring this until it truly ends.
+            // Also the interval between frame-stability samples: long enough that a zoom
+            // animation visibly moves the frame between two settles (so it keeps
+            // deferring), short enough that a still window nudges promptly.
             DispatchQueue.main.asyncAfter(deadline: .now() + 0.2, execute: work)
         }
 
@@ -105,12 +124,22 @@ struct ToolbarGlassKeeper: NSViewRepresentable {
             guard repairPending else { return }
             guard let window, window.occlusionState.contains(.visible) else {
                 repairPending = false
+                lastSampledFrame = nil
                 return
             }
             // Still resizing (a drag hasn't been let go) — wait for stability.
             if window.inLiveResize { scheduleSettle(); return }
-            repairPending = false
             let frame = window.frame
+            // A frame that changed since the last settle is still animating (a zoom in
+            // flight). Touching it now would cancel the zoom and revert the window, so
+            // re-sample and wait for two matching frames before nudging.
+            if lastSampledFrame != frame {
+                lastSampledFrame = frame
+                scheduleSettle()
+                return
+            }
+            repairPending = false
+            lastSampledFrame = nil
             guard frame.height > 2 else { return }
             // Shrink by a pixel (anchored at the top edge — AppKit's origin is
             // bottom-left, so raise the origin as height drops) then restore. Shrinking