portal: prevent feedback loop with the gtk4 hack to make it react to

color scheme changes

core/internal/matugen/matugen.go

@@ -912,6 +912,18 @@ func refreshGTK(mode ColorMode) {
 	}
 }
 
+var colorSchemeEchoHook func(scheme string)
+
+func SetColorSchemeEchoHook(hook func(scheme string)) {
+	colorSchemeEchoHook = hook
+}
+
+func expectColorSchemeEcho(scheme string) {
+	if colorSchemeEchoHook != nil {
+		colorSchemeEchoHook(scheme)
+	}
+}
+
 func refreshGTK4() {
 	output, err := utils.GsettingsGet("org.gnome.desktop.interface", "color-scheme")
 	if err != nil {
@@ -926,11 +938,13 @@ func refreshGTK4() {
 		toggle = "prefer-dark"
 	}
 
+	expectColorSchemeEcho(toggle)
 	if err := utils.GsettingsSet("org.gnome.desktop.interface", "color-scheme", toggle); err != nil {
 		log.Warnf("Failed to toggle color-scheme for GTK4 refresh: %v", err)
 		return
 	}
 	time.Sleep(50 * time.Millisecond)
+	expectColorSchemeEcho(current)
 	if err := utils.GsettingsSet("org.gnome.desktop.interface", "color-scheme", current); err != nil {
 		log.Warnf("Failed to restore color-scheme for GTK4 refresh: %v", err)
 	}

core/internal/server/freedesktop/manager.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"sync"
+	"time"
 
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/log"
 	"github.com/AvengeMedia/DankMaterialShell/core/pkg/dbusutil"
@@ -100,6 +101,41 @@ func (m *Manager) initializeSettings() error {
 	return nil
 }
 
+// ExpectColorSchemeEcho registers a self-write so the watcher swallows its SettingChanged echo instead of forwarding it as an external change.
+func (m *Manager) ExpectColorSchemeEcho(scheme string) {
+	var value uint32
+	switch scheme {
+	case "prefer-dark":
+		value = 1
+	case "prefer-light":
+		value = 2
+	}
+	m.selfEchoMu.Lock()
+	m.selfEchoes = append(m.selfEchoes, colorSchemeEcho{value: value, expires: time.Now().Add(10 * time.Second)})
+	m.selfEchoMu.Unlock()
+}
+
+func (m *Manager) consumeSelfEcho(value uint32) bool {
+	m.selfEchoMu.Lock()
+	defer m.selfEchoMu.Unlock()
+
+	now := time.Now()
+	kept := m.selfEchoes[:0]
+	consumed := false
+	for _, echo := range m.selfEchoes {
+		if now.After(echo.expires) {
+			continue
+		}
+		if !consumed && echo.value == value {
+			consumed = true
+			continue
+		}
+		kept = append(kept, echo)
+	}
+	m.selfEchoes = kept
+	return consumed
+}
+
 func (m *Manager) watchSettingsChanges() {
 	conn, err := dbus.ConnectSessionBus()
 	if err != nil {
@@ -142,13 +178,15 @@ func (m *Manager) watchSettingsChanges() {
 			continue
 		}
 
+		selfInflicted := m.consumeSelfEcho(colorScheme)
+
 		m.stateMutex.Lock()
 		changed := m.state.Settings.ColorScheme != colorScheme || !m.state.Settings.Available
 		m.state.Settings.ColorScheme = colorScheme
 		m.state.Settings.Available = true
 		m.stateMutex.Unlock()
 
-		if changed {
+		if changed && !selfInflicted {
 			m.NotifySubscribers()
 		}
 	}

core/internal/server/freedesktop/manager_test.go

@@ -141,3 +141,45 @@ func TestManager_SettingsState_Modification(t *testing.T) {
 	original := manager.GetState()
 	assert.Equal(t, uint32(0), original.Settings.ColorScheme)
 }
+
+func TestManager_SelfEcho_ConsumesRegisteredWrites(t *testing.T) {
+	manager := &Manager{state: &FreedeskState{}}
+
+	manager.ExpectColorSchemeEcho("prefer-dark")
+	manager.ExpectColorSchemeEcho("default")
+
+	assert.True(t, manager.consumeSelfEcho(1))
+	assert.True(t, manager.consumeSelfEcho(0))
+	assert.False(t, manager.consumeSelfEcho(1))
+	assert.False(t, manager.consumeSelfEcho(0))
+}
+
+func TestManager_SelfEcho_ExternalChangePassesThrough(t *testing.T) {
+	manager := &Manager{state: &FreedeskState{}}
+
+	manager.ExpectColorSchemeEcho("prefer-dark")
+
+	assert.False(t, manager.consumeSelfEcho(2))
+	assert.True(t, manager.consumeSelfEcho(1))
+}
+
+func TestManager_SelfEcho_ConsumesOnePerRegistration(t *testing.T) {
+	manager := &Manager{state: &FreedeskState{}}
+
+	manager.ExpectColorSchemeEcho("prefer-dark")
+	manager.ExpectColorSchemeEcho("prefer-dark")
+
+	assert.True(t, manager.consumeSelfEcho(1))
+	assert.True(t, manager.consumeSelfEcho(1))
+	assert.False(t, manager.consumeSelfEcho(1))
+}
+
+func TestManager_SelfEcho_SchemeMapping(t *testing.T) {
+	manager := &Manager{state: &FreedeskState{}}
+
+	manager.ExpectColorSchemeEcho("prefer-light")
+	assert.True(t, manager.consumeSelfEcho(2))
+
+	manager.ExpectColorSchemeEcho("default")
+	assert.True(t, manager.consumeSelfEcho(0))
+}

core/internal/server/freedesktop/types.go

@@ -2,11 +2,17 @@ package freedesktop
 
 import (
 	"sync"
+	"time"
 
 	"github.com/AvengeMedia/DankMaterialShell/core/pkg/syncmap"
 	"github.com/godbus/dbus/v5"
 )
 
+type colorSchemeEcho struct {
+	value   uint32
+	expires time.Time
+}
+
 type AccountsState struct {
 	Available     bool   `json:"available"`
 	UserPath      string `json:"userPath"`
@@ -63,4 +69,6 @@ type Manager struct {
 	screensaverCookieCounter      uint32
 	screensaverFreedesktopClaimed bool
 	screensaverGnomeClaimed       bool
+	selfEchoMu                    sync.Mutex
+	selfEchoes                    []colorSchemeEcho
 }

core/internal/server/server.go

@@ -17,6 +17,7 @@ import (
 
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/geolocation"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/log"
+	"github.com/AvengeMedia/DankMaterialShell/core/internal/matugen"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/apppicker"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/bluez"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/brightness"
@@ -190,6 +191,7 @@ func InitializeFreedeskManager() error {
 	}
 
 	freedesktopManager = manager
+	matugen.SetColorSchemeEchoHook(manager.ExpectColorSchemeEcho)
 
 	log.Info("Freedesktop manager initialized")
 	return nil

quickshell/Services/PortalService.qml

@@ -87,22 +87,43 @@ Singleton {
         }
     }
 
-    function evaluateColorScheme() {
+    function canSyncColorScheme() {
         if (typeof SettingsData === "undefined" || !SettingsData.syncModeWithPortal)
-            return;
+            return false;
         if (!settingsPortalAvailable)
-            return;
+            return false;
         if (typeof SessionData !== "undefined" && SessionData.themeModeAutoEnabled)
-            return;
-        if (typeof Theme === "undefined")
-            return;
-        // Defer mid-generation: setLightMode's regen would be dropped, and DMS's own transient color-scheme toggle would be misread. Re-run on worker completion.
-        if (Theme.workerRunning)
+            return false;
+        return typeof Theme !== "undefined";
+    }
+
+    // Only follow values stable for the settle window — the GTK4-refresh toggle reverts within ~50ms and following it would loop.
+    function evaluateColorScheme() {
+        if (!canSyncColorScheme())
             return;
         const shouldBeLight = systemColorScheme !== 1;
-        if (Theme.isLightMode === shouldBeLight)
+        if (Theme.isLightMode === shouldBeLight) {
+            colorSchemeSettleTimer.stop();
             return;
-        Theme.setLightMode(shouldBeLight, true, false);
+        }
+        colorSchemeSettleTimer.restart();
+    }
+
+    Timer {
+        id: colorSchemeSettleTimer
+        interval: 750
+        onTriggered: {
+            if (!root.canSyncColorScheme())
+                return;
+            const shouldBeLight = root.systemColorScheme !== 1;
+            if (Theme.isLightMode === shouldBeLight)
+                return;
+            if (Theme.workerRunning) {
+                restart();
+                return;
+            }
+            Theme.setLightMode(shouldBeLight, true, false);
+        }
     }
 
     function setLightMode(isLightMode) {