Add type hint all classes.

assets/AppAsset.php

@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * @link https://www.yiiframework.com/
  * @copyright Copyright (c) 2008 Yii Software LLC

commands/HelloController.php

@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * @link https://www.yiiframework.com/
  * @copyright Copyright (c) 2008 Yii Software LLC
@@ -18,14 +21,16 @@
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class HelloController extends Controller
+final class HelloController extends Controller
 {
     /**
      * This command echoes what you have entered as the message.
+     * 
      * @param string $message the message to be echoed.
+     * 
      * @return int Exit code
      */
-    public function actionIndex($message = 'hello world')
+    public function actionIndex(string $message = 'hello world'): int
     {
         echo $message . "\n";
 

controllers/SiteController.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace app\controllers;
 
 use Yii;
@@ -10,12 +12,12 @@
 use app\models\LoginForm;
 use app\models\ContactForm;
 
-class SiteController extends Controller
+final class SiteController extends Controller
 {
     /**
      * {@inheritdoc}
      */
-    public function behaviors()
+    public function behaviors(): array
     {
         return [
             'access' => [
@@ -41,7 +43,7 @@ public function behaviors()
     /**
      * {@inheritdoc}
      */
-    public function actions()
+    public function actions(): array
     {
         return [
             'error' => [
@@ -59,7 +61,7 @@ public function actions()
      *
      * @return string
      */
-    public function actionIndex()
+    public function actionIndex(): string
     {
         return $this->render('index');
     }
@@ -69,7 +71,7 @@ public function actionIndex()
      *
      * @return Response|string
      */
-    public function actionLogin()
+    public function actionLogin(): Response|string
     {
         if (!Yii::$app->user->isGuest) {
             return $this->goHome();
@@ -91,7 +93,7 @@ public function actionLogin()
      *
      * @return Response
      */
-    public function actionLogout()
+    public function actionLogout(): Response
     {
         Yii::$app->user->logout();
 
@@ -103,7 +105,7 @@ public function actionLogout()
      *
      * @return Response|string
      */
-    public function actionContact()
+    public function actionContact(): Response|string
     {
         $model = new ContactForm();
         if ($model->load(Yii::$app->request->post()) && $model->contact(Yii::$app->params['adminEmail'])) {
@@ -121,7 +123,7 @@ public function actionContact()
      *
      * @return string
      */
-    public function actionAbout()
+    public function actionAbout(): string
     {
         return $this->render('about');
     }

models/ContactForm.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace app\models;
 
 use Yii;
@@ -8,19 +10,19 @@
 /**
  * ContactForm is the model behind the contact form.
  */
-class ContactForm extends Model
+final class ContactForm extends Model
 {
-    public $name;
-    public $email;
-    public $subject;
-    public $body;
-    public $verifyCode;
+    public string $name = '';
+    public string $email = '';
+    public string $subject = '';
+    public string $body = '';
+    public string $verifyCode = '';
 
 
     /**
      * @return array the validation rules.
      */
-    public function rules()
+    public function rules(): array
     {
         return [
             // name, email, subject and body are required
@@ -35,7 +37,7 @@ public function rules()
     /**
      * @return array customized attribute labels
      */
-    public function attributeLabels()
+    public function attributeLabels(): array
     {
         return [
             'verifyCode' => 'Verification Code',
@@ -44,10 +46,12 @@ public function attributeLabels()
 
     /**
      * Sends an email to the specified email address using the information collected by this model.
+     * 
      * @param string $email the target email address
+     * 
      * @return bool whether the model passes validation
      */
-    public function contact($email)
+    public function contact(string $email): bool
     {
         if ($this->validate()) {
             Yii::$app->mailer->compose()

models/LoginForm.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace app\models;
 
 use Yii;
@@ -11,19 +13,19 @@
  * @property-read User|null $user
  *
  */
-class LoginForm extends Model
+final class LoginForm extends Model
 {
-    public $username;
-    public $password;
-    public $rememberMe = true;
+    public string $username = '';
+    public string $password = '';
+    public bool $rememberMe = true;
 
-    private $_user = false;
+    private bool|null|User $user = false;
 
 
     /**
      * @return array the validation rules.
      */
-    public function rules()
+    public function rules(): array
     {
         return [
             // username and password are both required
@@ -40,9 +42,9 @@ public function rules()
      * This method serves as the inline validation for password.
      *
      * @param string $attribute the attribute currently being validated
-     * @param array $params the additional name-value pairs given in the rule
+     * @param array|null $params the additional name-value pairs given in the rule
      */
-    public function validatePassword($attribute, $params)
+    public function validatePassword(string $attribute, array $params = null): void
     {
         if (!$this->hasErrors()) {
             $user = $this->getUser();
@@ -55,9 +57,10 @@ public function validatePassword($attribute, $params)
 
     /**
      * Logs in a user using the provided username and password.
+     * 
      * @return bool whether the user is logged in successfully
      */
-    public function login()
+    public function login(): bool
     {
         if ($this->validate()) {
             return Yii::$app->user->login($this->getUser(), $this->rememberMe ? 3600*24*30 : 0);
@@ -68,14 +71,14 @@ public function login()
     /**
      * Finds user by [[username]]
      *
-     * @return User|null
+     * @return User|null the user identity
      */
-    public function getUser()
+    public function getUser(): User|null
     {
-        if ($this->_user === false) {
-            $this->_user = User::findByUsername($this->username);
+        if ($this->user === false) {
+            $this->user = User::findByUsername($this->username);
         }
 
-        return $this->_user;
+        return $this->user;
     }
 }

models/User.php

@@ -1,14 +1,18 @@
 <?php
 
+declare(strict_types=1);
+
 namespace app\models;
 
-class User extends \yii\base\BaseObject implements \yii\web\IdentityInterface
+use yii\web\IdentityInterface;
+
+final class User extends \yii\base\BaseObject implements IdentityInterface
 {
-    public $id;
-    public $username;
-    public $password;
-    public $authKey;
-    public $accessToken;
+    public string $id;
+    public string $username;
+    public string $password;
+    public string $authKey;
+    public string $accessToken;
 
     private static array $users = [
         '100' => [
@@ -31,15 +35,15 @@ class User extends \yii\base\BaseObject implements \yii\web\IdentityInterface
     /**
      * {@inheritdoc}
      */
-    public static function findIdentity($id)
+    public static function findIdentity($id): IdentityInterface|null
     {
         return isset(self::$users[$id]) ? new static(self::$users[$id]) : null;
     }
 
     /**
      * {@inheritdoc}
      */
-    public static function findIdentityByAccessToken($token, $type = null)
+    public static function findIdentityByAccessToken($token, $type = null): IdentityInterface|null
     {
         foreach (self::$users as $user) {
             if ($user['accessToken'] === $token) {
@@ -53,10 +57,11 @@ public static function findIdentityByAccessToken($token, $type = null)
     /**
      * Finds user by username
      *
-     * @param string $username
-     * @return static|null
+     * @param string $username the username
+     * 
+     * @return static|null the user object
      */
-    public static function findByUsername($username)
+    public static function findByUsername($username): static|null
     {
         foreach (self::$users as $user) {
             if (strcasecmp((string) $user['username'], $username) === 0) {
@@ -70,23 +75,23 @@ public static function findByUsername($username)
     /**
      * {@inheritdoc}
      */
-    public function getId()
+    public function getId(): string
     {
         return $this->id;
     }
 
     /**
      * {@inheritdoc}
      */
-    public function getAuthKey()
+    public function getAuthKey(): string
     {
         return $this->authKey;
     }
 
     /**
      * {@inheritdoc}
      */
-    public function validateAuthKey($authKey)
+    public function validateAuthKey($authKey): bool
     {
         return $this->authKey === $authKey;
     }
@@ -95,9 +100,10 @@ public function validateAuthKey($authKey)
      * Validates password
      *
      * @param string $password password to validate
+     * 
      * @return bool if password provided is valid for current user
      */
-    public function validatePassword($password)
+    public function validatePassword(string $password): bool
     {
         return $this->password === $password;
     }

widgets/Alert.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace app\widgets;
 
 use Yii;
@@ -23,15 +25,15 @@
  * @author Kartik Visweswaran <kartikv2@gmail.com>
  * @author Alexander Makarov <sam@rmcreative.ru>
  */
-class Alert extends \yii\bootstrap5\Widget
+final class Alert extends \yii\bootstrap5\Widget
 {
     /**
      * @var array the alert types configuration for the flash messages.
      * This array is setup as $key => $value, where:
      * - key: the name of the session flash variable
      * - value: the bootstrap alert type (i.e. danger, success, info, warning)
      */
-    public $alertTypes = [
+    public array $alertTypes = [
         'error'   => 'alert-danger',
         'danger'  => 'alert-danger',
         'success' => 'alert-success',
@@ -42,7 +44,7 @@ class Alert extends \yii\bootstrap5\Widget
      * @var array the options for rendering the close button tag.
      * Array will be passed to [[\yii\bootstrap\Alert::closeButton]].
      */
-    public $closeButton = [];
+    public array $closeButton = [];
 
 
     /**