cocoa: re-assert applicationIconImage when switching to Regular

go.mod

@@ -3,7 +3,7 @@ module github.com/go-widgets/window
 go 1.26.4
 
 require (
-	github.com/go-macos/objc v0.9.1
+	github.com/go-macos/objc v0.10.1
 	github.com/go-mswin/win32 v0.4.0
 	github.com/go-opentype/opentype v0.12.0
 	github.com/go-widgets/android v0.13.1

go.sum

@@ -30,8 +30,8 @@ github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
 github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
 github.com/go-macos/appkit v0.5.0 h1:4LeIstgHaKcoTk4Eb0qFoHmUVa7arW1NNZAO8VLJtfQ=
 github.com/go-macos/appkit v0.5.0/go.mod h1:KQ+vIsZ2hBFniqFJ5Q4uQ4ylQX+MXPvJcMOzvBpJRdE=
-github.com/go-macos/objc v0.9.1 h1:GGBoj8aMijBCYNPjGAYS4neeA3lWa8/JEIF1K5GswDo=
-github.com/go-macos/objc v0.9.1/go.mod h1:00GJyieLzPcb65rPLVWNPPUCVm79nmmiEXUDsslRpOs=
+github.com/go-macos/objc v0.10.1 h1:uXOc5w3Hp6FLB9RwmxbSY7ZyUKg37j/VOT2DjxPfmDU=
+github.com/go-macos/objc v0.10.1/go.mod h1:68hzSUlhg5bFbg1kO0z4DM6xOk4B/IofuxdlyhHHtt8=
 github.com/go-macos/virtualdisplay v0.3.0 h1:OWo8bGaXWEGutoGHO/RV9qO5Lzfe1hFx2aXNocZ4bHI=
 github.com/go-macos/virtualdisplay v0.3.0/go.mod h1:68/38e3PlQ3cwK7du2wflPaNan+DQqKz7Hhi89uo6gg=
 github.com/go-mswin/win32 v0.4.0 h1:0JAvm3XNMxOyfYX1anbtAqxNvxvUA0DZ1SyAUinhMa0=

internal/cocoa/cocoa_darwin.go

@@ -92,6 +92,8 @@ var (
 	selRelease               = objc.RegisterName("release")
 	selSetActivationPolicy   = objc.RegisterName("setActivationPolicy:")
 	selActivateIgnoring      = objc.RegisterName("activateIgnoringOtherApps:")
+	selApplicationIconImage  = objc.RegisterName("applicationIconImage")
+	selSetApplicationIcon    = objc.RegisterName("setApplicationIconImage:")
 	selNextEvent             = objc.RegisterName("nextEventMatchingMask:untilDate:inMode:dequeue:")
 	selSendEvent             = objc.RegisterName("sendEvent:")
 	selRun                   = objc.RegisterName("run")
@@ -722,6 +724,20 @@ func NewWithOptions(o Options) (*Window, error) {
 		policy = activationPolicyAccessory
 	}
 	app.Send(selSetActivationPolicy, policy)
+	// A caller that set applicationIconImage before ever becoming Regular
+	// (an accessory app's own startup, before its first window) has
+	// nothing live to land on: there is no Dock tile yet to update. Apple's
+	// own DTS guidance on exactly this Accessory<->Regular pattern is that
+	// the Dock's reaction to a runtime icon change is not instant and can
+	// revert unexpectedly across a policy transition — re-asserting the
+	// SAME image here, right as a real Dock tile is about to exist, is
+	// what actually lands it. A caller that never set one gets nil back
+	// and this is a harmless no-op re-assignment of nil to nil.
+	if policy == activationPolicyReg {
+		if icon := app.Send(selApplicationIconImage); icon != 0 {
+			app.Send(selSetApplicationIcon, icon)
+		}
+	}
 	syncAppKitScreens(appKitScreenSyncTimeout)
 
 	screen, err := o.resolveScreen()

internal/cocoa/live_darwin_test.go

@@ -574,3 +574,67 @@ func TestLiveWindowNumberIsTheCGWindowID(t *testing.T) {
 	}
 	callOnMain(func() { win.Close() })
 }
+
+// TestApplicationIconSurvivesAccessoryToRegular covers the regression this
+// package's Regular-policy re-assert exists for: an accessory-policy
+// process (a menu-bar app) that already set applicationIconImage at its
+// own startup — before ever having a Dock tile to update — must still
+// show that icon once a real window (this package's own NewWithOptions)
+// switches it to Regular. Apple's own DTS guidance on this exact
+// Accessory<->Regular pattern is that the Dock's reaction to a runtime
+// icon change is not instant and can revert unexpectedly across a policy
+// transition; live-verified on-device (a real Dock tile, screenshotted)
+// that WITHOUT the re-assert this package now does, the tile showed a
+// generic icon despite applicationIconImage correctly reporting the
+// custom one throughout.
+func TestApplicationIconSurvivesAccessoryToRegular(t *testing.T) {
+	if os.Getenv("WINDOW_COCOA_INTEGRATION") == "" {
+		t.Skip("set WINDOW_COCOA_INTEGRATION=1 to run the live macOS window proof")
+	}
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, image.NewNRGBA(image.Rect(0, 0, 8, 8))); err != nil {
+		t.Fatalf("encoding a test PNG: %v", err)
+	}
+
+	// applicationIconImage lives on the one shared NSApplication every test
+	// in this binary runs against — left set, it would silently change
+	// window-creation timing for every test declared after this one
+	// (alphabetically, that includes liverepaint_darwin_test.go), not just
+	// this test's own assertions.
+	t.Cleanup(func() {
+		callOnMain(func() { objc.App().Send(objc.RegisterName("setApplicationIconImage:"), objc.ID(0)) })
+	})
+
+	var win *Window
+	var err error
+	var sizeBeforeOpen, sizeAfterOpen toolkit.Rect
+	callOnMain(func() {
+		app := objc.App()
+		app.Send(objc.RegisterName("setActivationPolicy:"), 1) // Accessory
+		app.Send(objc.RegisterName("finishLaunching"))
+		objc.SetApplicationIconImage(buf.Bytes())
+
+		icon := app.Send(objc.RegisterName("applicationIconImage"))
+		sz := objc.Send[nsSize](icon, objc.RegisterName("size"))
+		sizeBeforeOpen = toolkit.Rect{W: int(sz.W), H: int(sz.H)}
+
+		win, err = New("dock icon proof", 200, 120, toolkit.DefaultDark())
+		if err != nil {
+			return
+		}
+		icon = app.Send(objc.RegisterName("applicationIconImage"))
+		sz = objc.Send[nsSize](icon, objc.RegisterName("size"))
+		sizeAfterOpen = toolkit.Rect{W: int(sz.W), H: int(sz.H)}
+	})
+	if err != nil {
+		t.Fatalf("New: %v", err)
+	}
+	defer callOnMain(func() { win.Close() })
+
+	if sizeBeforeOpen.W == 0 || sizeBeforeOpen.H == 0 {
+		t.Fatal("setup: applicationIconImage was not set before opening the window")
+	}
+	if sizeAfterOpen != sizeBeforeOpen {
+		t.Errorf("applicationIconImage changed across the Accessory->Regular transition: before=%+v after=%+v", sizeBeforeOpen, sizeAfterOpen)
+	}
+}