Use a flag to implement a fallback when the feature is disabled

Author: 0nko

app/src/main/java/com/duckduckgo/app/browser/BrowserActivity.kt

@@ -346,13 +346,6 @@ open class BrowserActivity : DuckDuckGoActivity() {
 
         super.onCreate(savedInstanceState = newInstanceState, daggerInject = false)
 
-        // safety check: if the omnibar type is SPLIT but the feature is disabled, reset to SINGLE_TOP
-        if (settingsDataStore.omnibarType == OmnibarType.SPLIT &&
-            (!browserFeatures.useUnifiedOmnibarLayout().isEnabled() || !browserFeatures.splitOmnibar().isEnabled())
-        ) {
-            settingsDataStore.omnibarType = OmnibarType.SINGLE_TOP
-        }
-
         bindMockupToolbars()
 
         setContentView(binding.root)

app/src/main/java/com/duckduckgo/app/browser/omnibar/SplitOmnibarFallbackObserver.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2025 DuckDuckGo
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.duckduckgo.app.browser.omnibar
+
+import androidx.lifecycle.LifecycleOwner
+import com.duckduckgo.app.lifecycle.MainProcessLifecycleObserver
+import com.duckduckgo.app.pixels.remoteconfig.AndroidBrowserConfigFeature
+import com.duckduckgo.app.settings.db.SettingsDataStore
+import com.duckduckgo.browser.ui.omnibar.OmnibarType
+import com.duckduckgo.di.scopes.AppScope
+import com.squareup.anvil.annotations.ContributesMultibinding
+import javax.inject.Inject
+
+/**
+ * Observes app lifecycle to ensure that if the Split Omnibar feature is disabled via remote config,
+ * and the user had selected the Split Omnibar, we revert to Single Top Omnibar.
+ * If the feature is re-enabled, we restore the user's choice.
+ */
+@ContributesMultibinding(
+    scope = AppScope::class,
+    boundType = MainProcessLifecycleObserver::class,
+)
+class SplitOmnibarFallbackObserver @Inject constructor(
+    private val settingsDataStore: SettingsDataStore,
+    private val browserFeatures: AndroidBrowserConfigFeature,
+) : MainProcessLifecycleObserver {
+    override fun onStart(owner: LifecycleOwner) {
+        super.onStart(owner)
+
+        if (settingsDataStore.omnibarType == OmnibarType.SPLIT &&
+            (!browserFeatures.useUnifiedOmnibarLayout().isEnabled() || !browserFeatures.splitOmnibar().isEnabled())
+        ) {
+            settingsDataStore.isSplitOmnibarSelected = true
+            settingsDataStore.omnibarType = OmnibarType.SINGLE_TOP
+        } else if (settingsDataStore.isSplitOmnibarSelected &&
+            browserFeatures.useUnifiedOmnibarLayout().isEnabled() &&
+            browserFeatures.splitOmnibar().isEnabled()
+        ) {
+            // Restore user's choice if the feature is re-enabled
+            settingsDataStore.omnibarType = OmnibarType.SPLIT
+            settingsDataStore.isSplitOmnibarSelected = false
+        }
+    }
+}

app/src/main/java/com/duckduckgo/app/settings/db/SettingsDataStore.kt

@@ -68,6 +68,9 @@ interface SettingsDataStore {
     var showAutomaticFireproofDialog: Boolean
     var omnibarType: OmnibarType
 
+    // Temporary cache value for split omnibar feature, in case the flag is temporarily disabled
+    var isSplitOmnibarSelected: Boolean
+
     /**
      * This will be checked upon app startup and used to decide whether it should perform a clear or not.
      * If the app is cleared and the process restarted as a result, then we don't want to clear and restart again when the app launches.
@@ -219,6 +222,10 @@ class SettingsSharedPreferences @Inject constructor(
         )
         set(value) = preferences.edit { putString(KEY_OMNIBAR_TYPE, value.typeName) }
 
+    override var isSplitOmnibarSelected: Boolean
+        get() = preferences.getBoolean(KEY_SPLIT_OMNIBAR, false)
+        set(value) = preferences.edit { putBoolean(KEY_SPLIT_OMNIBAR, value) }
+
     override var isFullUrlEnabled: Boolean
         get() = preferences.getBoolean(KEY_IS_FULL_URL_ENABLED, true)
         set(enabled) = preferences.edit { putBoolean(KEY_IS_FULL_URL_ENABLED, enabled) }
@@ -300,6 +307,7 @@ class SettingsSharedPreferences @Inject constructor(
         const val KEY_NOTIFY_ME_IN_DOWNLOADS_DISMISSED = "KEY_NOTIFY_ME_IN_DOWNLOADS_DISMISSED"
         const val KEY_EXPERIMENTAL_SITE_DARK_MODE = "KEY_EXPERIMENTAL_SITE_DARK_MODE"
         const val KEY_OMNIBAR_TYPE = "KEY_OMNIBAR_POSITION"
+        const val KEY_SPLIT_OMNIBAR = "KEY_SPLIT_OMNIBAR"
         const val KEY_IS_FULL_URL_ENABLED = "KEY_IS_FULL_URL_ENABLED"
         const val KEY_CLEAR_DUCK_AI_DATA = "KEY_CLEAR_DUCK_AI_DATA"
     }