Minor cleanup.

src/Authenticator/CookieAuthenticator.php

@@ -84,7 +84,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
 
         $identity = $this->_identifier->identify(compact('username'));
 
-        if (empty($identity)) {
+        if (!$identity) {
             return new Result(null, Result::FAILURE_IDENTITY_NOT_FOUND, $this->_identifier->getErrors());
         }
 

src/Authenticator/EnvironmentAuthenticator.php

@@ -137,7 +137,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
             return $this->_buildLoginUrlErrorResult($request);
         }
         $data = $this->_getData($request);
-        if (empty($data)) {
+        if (!$data) {
             return new Result(null, Result::FAILURE_CREDENTIALS_MISSING, [
                 'Environment credentials not found',
             ]);
@@ -147,7 +147,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
 
         $user = $this->_identifier->identify($data);
 
-        if (empty($user)) {
+        if (!$user) {
             return new Result(null, Result::FAILURE_IDENTITY_NOT_FOUND, $this->_identifier->getErrors());
         }
 

src/Authenticator/FormAuthenticator.php

@@ -130,7 +130,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
 
         $user = $this->_identifier->identify($data);
 
-        if (empty($user)) {
+        if (!$user) {
             return new Result(null, Result::FAILURE_IDENTITY_NOT_FOUND, $this->_identifier->getErrors());
         }
 

src/Authenticator/HttpDigestAuthenticator.php

@@ -98,7 +98,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
             AbstractIdentifier::CREDENTIAL_USERNAME => $digest['username'],
         ]);
 
-        if (empty($user)) {
+        if (!$user) {
             return new Result(null, Result::FAILURE_IDENTITY_NOT_FOUND);
         }
 
@@ -132,13 +132,13 @@ protected function _getDigest(ServerRequestInterface $request): ?array
     {
         $server = $request->getServerParams();
         $digest = empty($server['PHP_AUTH_DIGEST']) ? null : $server['PHP_AUTH_DIGEST'];
-        if (empty($digest) && function_exists('apache_request_headers')) {
+        if (!$digest && function_exists('apache_request_headers')) {
             $headers = apache_request_headers();
             if (!empty($headers['Authorization']) && substr($headers['Authorization'], 0, 7) === 'Digest ') {
                 $digest = substr($headers['Authorization'], 7);
             }
         }
-        if (empty($digest)) {
+        if (!$digest) {
             return null;
         }
 
@@ -165,7 +165,7 @@ public function parseAuthData(string $digest): ?array
             unset($req[$i[1]]);
         }
 
-        if (empty($req)) {
+        if (!$req) {
             return $keys;
         }
 

src/Authenticator/JwtAuthenticator.php

@@ -110,7 +110,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
             $subjectKey => $result[$subjectKey],
         ]);
 
-        if (empty($user)) {
+        if (!$user) {
             return new Result(null, Result::FAILURE_IDENTITY_NOT_FOUND, $this->_identifier->getErrors());
         }
 

src/Authenticator/SessionAuthenticator.php

@@ -60,7 +60,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
         $session = $request->getAttribute('session');
         $user = $session->read($sessionKey);
 
-        if (empty($user)) {
+        if (!$user) {
             return new Result(null, Result::FAILURE_IDENTITY_NOT_FOUND);
         }
 
@@ -71,7 +71,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
             }
             $user = $this->_identifier->identify($credentials);
 
-            if (empty($user)) {
+            if (!$user) {
                 return new Result(null, Result::FAILURE_CREDENTIALS_INVALID);
             }
         }

src/Authenticator/TokenAuthenticator.php

@@ -75,9 +75,9 @@ protected function stripTokenPrefix(string $token, string $prefix): string
      */
     protected function getTokenFromHeader(ServerRequestInterface $request, ?string $headerLine): ?string
     {
-        if (!empty($headerLine)) {
+        if ($headerLine) {
             $header = $request->getHeaderLine($headerLine);
-            if (!empty($header)) {
+            if ($header) {
                 return $header;
             }
         }
@@ -89,12 +89,12 @@ protected function getTokenFromHeader(ServerRequestInterface $request, ?string $
      * Gets the token from the request query
      *
      * @param \Psr\Http\Message\ServerRequestInterface $request The request that contains login information.
-     * @param string $queryParam Request query parameter name
+     * @param string|null $queryParam Request query parameter name
      * @return string|null
      */
     protected function getTokenFromQuery(ServerRequestInterface $request, ?string $queryParam): ?string
     {
-        if (empty($queryParam)) {
+        if (!$queryParam) {
             return null;
         }
 
@@ -123,7 +123,7 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
             TokenIdentifier::CREDENTIAL_TOKEN => $token,
         ]);
 
-        if (empty($user)) {
+        if (!$user) {
             return new Result(null, Result::FAILURE_IDENTITY_NOT_FOUND, $this->_identifier->getErrors());
         }
 

src/UrlChecker/DefaultUrlChecker.php

@@ -44,8 +44,7 @@ public function check(ServerRequestInterface $request, $loginUrls, array $option
         $options = $this->_mergeDefaultOptions($options);
 
         $urls = (array)$loginUrls;
-
-        if (empty($urls)) {
+        if (!$urls) {
             return true;
         }
 

src/View/Helper/IdentityHelper.php

@@ -110,7 +110,7 @@ public function is(int|string $id, string $field = 'id'): bool
      */
     public function get(?string $key = null): mixed
     {
-        if (empty($this->_identity)) {
+        if ($this->_identity === null) {
             return null;
         }