Restore session use in Auth\Manager::once() when authentication throws

src/Auth/Manager.php

@@ -622,11 +622,16 @@ public function id()
      */
     public function once(array $credentials = [])
     {
-        $this->useSession = false;
+        $previousUseSession = $this->useSession;
 
-        $user = $this->authenticate($credentials);
+        $this->useSession = false;
 
-        $this->useSession = true;
+        try {
+            $user = $this->authenticate($credentials);
+        }
+        finally {
+            $this->useSession = $previousUseSession;
+        }
 
         return !!$user;
     }

tests/Auth/ManagerOnceTest.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace Winter\Storm\Tests\Auth;
+
+use ReflectionProperty;
+use RuntimeException;
+use Winter\Storm\Auth\Manager as AuthManager;
+
+class ManagerOnceTest extends \Winter\Storm\Tests\TestCase
+{
+    public function tearDown(): void
+    {
+        ManagerOnceTestThrowingManager::forgetInstance();
+
+        parent::tearDown();
+    }
+
+    public function testOnceRestoresSessionUseWhenAuthenticationThrows()
+    {
+        $manager = ManagerOnceTestThrowingManager::instance();
+
+        $this->assertTrue($this->getUseSession($manager));
+
+        try {
+            $manager->once(['login' => 'someone', 'password' => 'secret']);
+            $this->fail('The exception from authenticate() should propagate.');
+        }
+        catch (RuntimeException $ex) {
+            // Expected.
+        }
+
+        $this->assertTrue($this->getUseSession($manager));
+    }
+
+    public function testOnceRestoresThePreviousValueRatherThanTrue()
+    {
+        $manager = ManagerOnceTestThrowingManager::instance();
+        (new ReflectionProperty($manager, 'useSession'))->setValue($manager, false);
+
+        try {
+            $manager->once(['login' => 'someone', 'password' => 'secret']);
+        }
+        catch (RuntimeException $ex) {
+            // Expected.
+        }
+
+        $this->assertFalse($this->getUseSession($manager));
+    }
+
+    protected function getUseSession(AuthManager $manager): bool
+    {
+        return (new ReflectionProperty($manager, 'useSession'))->getValue($manager);
+    }
+}
+
+class ManagerOnceTestThrowingManager extends AuthManager
+{
+    public function authenticate(array $credentials, $remember = true)
+    {
+        throw new RuntimeException('authentication failed');
+    }
+}