ci: bring :app and :e2eTest under the Android Lint gate

.github/workflows/lint.yml

@@ -0,0 +1,46 @@
+name: Android Lint
+
+# pull_request only, matching e2e_test.yml. android.yml's [pull_request, push]
+# is why every commit there produces two identical `build` runs.
+on:
+  - pull_request
+
+permissions:
+  contents: read
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Cache Gradle packages
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@dd06d9cba3e5552c54d9f8ea23572deb30010f7c # v6.0.0
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+
+      # lintAll gates :app and :proguard-tests, both of which apply the google-services
+      # plugin and will not configure without this file. Mirrors what build.sh copies.
+      - name: Copy google-services.json
+        run: |
+          cp library/google-services.json app/google-services.json
+          cp library/google-services.json proguard-tests/google-services.json
+
+      - name: Android Lint
+        run: ./gradlew --max-workers=2 lintAll
+
+      - name: Print Logs
+        if: failure()
+        run: ./scripts/print_build_logs.sh

app/build.gradle.kts

@@ -6,6 +6,9 @@ plugins {
     id("org.jetbrains.kotlin.plugin.compose")
     id("com.google.gms.google-services")
     id("kotlin-kapt")
+    // The slot demos host the auth screens on their own Navigation 3 back stacks, and a
+    // rememberNavBackStack key has to be @Serializable to survive process death.
+    alias(libs.plugins.kotlin.serialization)
 }
 
 android {
@@ -36,6 +39,26 @@ android {
             }
         }
     }
+
+    lint {
+        // Module specific
+        disable += mutableSetOf(
+            // Reads the root wrapper, but only the application module analyses it, so it
+            // belongs here rather than in the shared policy. For reproducible builds.
+            "AndroidGradlePluginVersion",
+            // The demos log their auth callbacks unconditionally on purpose — watching
+            // logcat is how you see one fire. Unlike :auth's, none of these log user data.
+            "LogConditional",
+            // Glide's KSP processor does not generate GlideApp, which the storage demo and
+            // storage/README.md are both written around. Migration tracked separately.
+            "KaptUsageInsteadOfKsp",
+            // A themed icon needs a flat silhouette drawn for the purpose. The only
+            // candidate here is ic_launcher_foreground, whose opaque region is a solid
+            // plate, so it tints to a featureless block — worse than no monochrome layer.
+            "MonochromeLauncherIcon"
+        )
+    }
+
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_17
         targetCompatibility = JavaVersion.VERSION_17

app/src/main/AndroidManifest.xml

@@ -14,15 +14,20 @@
         android:usesCleartextTraffic="true">
         <activity
             android:name="com.firebaseui.android.demo.MainActivity"
-            android:label="@string/app_name"
             android:exported="true"
             android:theme="@style/Theme.FirebaseUIAndroid">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
 
-            <intent-filter android:autoVerify="true">
+            <!--
+                The host is a placeholder the demo's own Firebase project fills in, so lint
+                can neither read it as a domain nor resolve it over the network.
+            -->
+            <intent-filter
+                android:autoVerify="true"
+                tools:ignore="AppLinkUrlError,AppLinksAutoVerify">
                 <action android:name="android.intent.action.VIEW" />
                 <category android:name="android.intent.category.DEFAULT" />
                 <category android:name="android.intent.category.BROWSABLE" />

app/src/main/java/com/firebaseui/android/demo/auth/AuthChooserActivity.kt

@@ -78,7 +78,7 @@ fun AuthChooserScreen(
         verticalArrangement = Arrangement.spacedBy(24.dp)
     ) {
         Spacer(modifier = Modifier.height(16.dp))
-        // Header
+
         Text(
             text = "Firebase Auth UI Compose",
             style = MaterialTheme.typography.headlineLarge,
@@ -92,7 +92,6 @@ fun AuthChooserScreen(
             color = MaterialTheme.colorScheme.onSurfaceVariant
         )
 
-        // Emulator Mode Warning
         if (isEmulatorMode) {
             Card(
                 modifier = Modifier.fillMaxWidth(),
@@ -121,7 +120,6 @@ fun AuthChooserScreen(
             }
         }
 
-        // High-Level API Card
         Card(
             modifier = Modifier.fillMaxWidth(),
             onClick = onHighLevelApiClick
@@ -157,7 +155,6 @@ fun AuthChooserScreen(
             }
         }
 
-        // Low-Level API Card
         Card(
             modifier = Modifier.fillMaxWidth(),
             onClick = onLowLevelApiClick
@@ -193,7 +190,6 @@ fun AuthChooserScreen(
             }
         }
 
-        // Custom Slots & Theming Card
         Card(
             modifier = Modifier.fillMaxWidth(),
             onClick = onCustomSlotsClick
@@ -229,7 +225,6 @@ fun AuthChooserScreen(
             }
         }
 
-        // Credential Linking Card
         Card(
             modifier = Modifier.fillMaxWidth(),
             onClick = onCredentialLinkingClick
@@ -257,7 +252,6 @@ fun AuthChooserScreen(
 
         Spacer(modifier = Modifier.height(16.dp))
 
-        // Info card
         Card(
             modifier = Modifier.fillMaxWidth(),
             colors = CardDefaults.cardColors(

app/src/main/java/com/firebaseui/android/demo/auth/AuthFlowControllerDemoActivity.kt

@@ -27,27 +27,23 @@ import com.google.firebase.auth.actionCodeSettings
 import kotlinx.coroutines.launch
 
 /**
- * Demo activity showcasing the AuthFlowController API for managing
- * Firebase authentication with lifecycle-safe control.
+ * Drives the auth flow from an Activity with [AuthFlowController], instead of composing
+ * `FirebaseAuthScreen` directly.
  *
- * This demonstrates:
- * - Creating an AuthFlowController with configuration
- * - Starting the auth flow using ActivityResultLauncher
- * - Observing auth state changes
- * - Handling results (success, cancelled, error)
- * - Proper lifecycle management with dispose()
+ * The flow runs in its own Activity, so its outcome arrives as an Activity result. That result
+ * only reports that the flow ended, which is why the demo also collects `authStateFlow` and
+ * registers an `AuthStateListener` beside it — those are what report progress and the signed-in
+ * user. Disposing the controller in `onDestroy` is the contract [AuthFlowController] documents.
  */
 class AuthFlowControllerDemoActivity : ComponentActivity() {
 
     private lateinit var authController: AuthFlowController
 
-    // Modern ActivityResultLauncher for auth flow
     private val authLauncher = registerForActivityResult(
         ActivityResultContracts.StartActivityForResult()
     ) { result ->
         when (result.resultCode) {
             Activity.RESULT_OK -> {
-                // Get user data from result
                 val userId = result.data?.getStringExtra(FirebaseAuthActivity.EXTRA_USER_ID)
                 val isNewUser = result.data?.getBooleanExtra(
                     FirebaseAuthActivity.EXTRA_IS_NEW_USER,
@@ -71,10 +67,8 @@ class AuthFlowControllerDemoActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
-        // Initialize FirebaseAuthUI
         val authUI = FirebaseAuthUI.getInstance()
 
-        // Create auth configuration
         val configuration = AuthUIConfiguration(
             context = applicationContext,
             providers = listOf(
@@ -103,7 +97,6 @@ class AuthFlowControllerDemoActivity : ComponentActivity() {
                     defaultNumber = null,
                     defaultCountryCode = null,
                     allowedCountries = emptyList(),
-                    smsCodeLength = 6,
                     timeout = 120L,
                     isInstantVerificationEnabled = true
                 ),
@@ -113,7 +106,6 @@ class AuthFlowControllerDemoActivity : ComponentActivity() {
             privacyPolicyUrl = "https://policies.google.com/privacy?hl=en-NG&fg=1"
         )
 
-        // Create AuthFlowController
         authController = authUI.createAuthFlow(configuration)
 
         setContent {
@@ -134,7 +126,6 @@ class AuthFlowControllerDemoActivity : ComponentActivity() {
 
     override fun onDestroy() {
         super.onDestroy()
-        // Clean up resources
         authController.dispose()
     }
 
@@ -164,7 +155,6 @@ fun AuthFlowDemo(
     val authState by authController.authStateFlow.collectAsState(AuthState.Idle)
     var currentUser by remember { mutableStateOf(FirebaseAuth.getInstance().currentUser) }
 
-    // Observe Firebase auth state changes
     DisposableEffect(Unit) {
         val authStateListener = FirebaseAuth.AuthStateListener { auth ->
             currentUser = auth.currentUser
@@ -205,7 +195,6 @@ fun AuthFlowDemo(
 
         Spacer(modifier = Modifier.height(16.dp))
 
-        // Current Auth State Card
         Card(
             modifier = Modifier.fillMaxWidth(),
             colors = CardDefaults.cardColors(
@@ -243,7 +232,6 @@ fun AuthFlowDemo(
             }
         }
 
-        // Current User Card
         currentUser?.let { user ->
             Card(
                 modifier = Modifier.fillMaxWidth(),
@@ -274,7 +262,6 @@ fun AuthFlowDemo(
 
         Spacer(modifier = Modifier.height(16.dp))
 
-        // Action Buttons
         if (currentUser == null) {
             Button(
                 onClick = onStartAuth,
@@ -302,7 +289,6 @@ fun AuthFlowDemo(
             }
         }
 
-        // Info Card
         Card(
             modifier = Modifier.fillMaxWidth()
         ) {

app/src/main/java/com/firebaseui/android/demo/auth/EmailAuthSlotDemoActivity.kt

@@ -39,6 +39,11 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.input.PasswordVisualTransformation
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
+import androidx.navigation3.runtime.NavBackStack
+import androidx.navigation3.runtime.NavKey
+import androidx.navigation3.runtime.entryProvider
+import androidx.navigation3.runtime.rememberNavBackStack
+import androidx.navigation3.ui.NavDisplay
 import com.firebase.ui.auth.AuthException
 import com.firebase.ui.auth.FirebaseAuthUI
 import com.firebase.ui.auth.configuration.AuthUIConfiguration
@@ -51,6 +56,33 @@ import com.firebase.ui.auth.ui.screens.email.EmailAuthContentState
 import com.firebase.ui.auth.ui.screens.email.EmailAuthMode
 import com.firebase.ui.auth.ui.screens.email.EmailAuthScreen
 import com.google.firebase.auth.AuthResult
+import kotlinx.serialization.Serializable
+
+/**
+ * One email mode, as this demo's own back-stack key.
+ *
+ * The library's navigation keys are its own business — a caller hosting [EmailAuthScreen] outside
+ * `FirebaseAuthScreen` brings its own, built from the public [EmailAuthMode] and the address the
+ * screen hands back. Distinct keys are distinct entries, so every mode composes fresh and system
+ * back pops one mode at a time.
+ */
+@Serializable
+private data class EmailModeKey(val mode: EmailAuthMode, val email: String = "") : NavKey
+
+/**
+ * Moves to [mode], carrying the address so a switch keeps what the user typed.
+ *
+ * Adds before trimming, so no single write empties the stack: a mode already on the stack is
+ * replaced by the fresh key rather than revisited with a stale address; one that is not is pushed,
+ * leaving the mode below reachable by back.
+ */
+private fun NavBackStack<NavKey>.goToEmailMode(mode: EmailAuthMode, email: String) {
+    val existing = indexOfFirst { it is EmailModeKey && it.mode == mode }
+    add(EmailModeKey(mode, email))
+    if (existing >= 0) {
+        while (size > existing + 1) removeAt(existing)
+    }
+}
 
 class EmailAuthSlotDemoActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -133,6 +165,12 @@ fun EmailAuthDemo(
         }
     }
 
+    // Every mode is a real destination on this demo's own stack, so system back steps between modes
+    // instead of leaving the flow. Allocated above the branch: a rememberSaveable must not sit
+    // behind one, or signing out and back in restores it against a composition that no longer
+    // matches.
+    val backStack = rememberNavBackStack(EmailModeKey(EmailAuthMode.SignIn))
+
     if (currentUser != null) {
         Column(
             modifier = Modifier
@@ -160,22 +198,42 @@ fun EmailAuthDemo(
         }
     } else {
         CompositionLocalProvider(LocalAuthUIStringProvider provides configuration.stringProvider) {
-            EmailAuthScreen(
-                context = context,
-                configuration = configuration,
-                authUI = authUI,
-                onSuccess = { result: AuthResult ->
-                    Log.d("EmailAuthSlotDemo", "Auth success: ${result.user?.uid}")
-                },
-                onError = { exception: AuthException ->
-                    Log.e("EmailAuthSlotDemo", "Auth error", exception)
+            NavDisplay(
+                backStack = backStack,
+                // Guarded like the library's popOrNull: NavDisplay throws on an empty
+                // stack, and throws from recomposition, so the first mode must not pop.
+                onBack = { if (backStack.size > 1) backStack.removeLastOrNull() },
+                entryProvider = entryProvider {
+                    entry<EmailModeKey> { key ->
+                        EmailAuthScreen(
+                            context = context,
+                            configuration = configuration,
+                            authUI = authUI,
+                            prefillEmail = key.email.ifEmpty { null },
+                            mode = key.mode,
+                            onNavigateToMode = { mode, email ->
+                                backStack.goToEmailMode(mode, email)
+                            },
+                            onSuccess = { result: AuthResult ->
+                                Log.d("EmailAuthSlotDemo", "Auth success: ${result.user?.uid}")
+                            },
+                            onError = { exception: AuthException ->
+                                Log.e("EmailAuthSlotDemo", "Auth error", exception)
+                            },
+                            onCancel = {
+                                // Below the start mode there is nothing left to pop back to.
+                                if (backStack.size > 1) {
+                                    backStack.removeLastOrNull()
+                                } else {
+                                    Log.d("EmailAuthSlotDemo", "Auth cancelled")
+                                }
+                            }
+                        ) { state: EmailAuthContentState ->
+                            CustomEmailAuthUI(state)
+                        }
+                    }
                 },
-                onCancel = {
-                    Log.d("EmailAuthSlotDemo", "Auth cancelled")
-                }
-            ) { state: EmailAuthContentState ->
-                CustomEmailAuthUI(state)
-            }
+            )
         }
     }
 }