feat: guard Deployer singleton before Host construction

src/Deployer.php

@@ -66,7 +66,7 @@
  */
 class Deployer extends Container
 {
-    private static Deployer $instance;
+    private static ?self $instance = null;
 
     public function __construct(Application $console)
     {
@@ -167,9 +167,21 @@ public function __construct(Application $console)
 
     public static function get(): self
     {
+        if (self::$instance === null) {
+            throw new \RuntimeException('Deployer is not initialized.');
+        }
+
         return self::$instance;
     }
 
+    /**
+     * @internal For tests that need a clean Deployer singleton between cases.
+     */
+    public static function resetInstance(): void
+    {
+        self::$instance = null;
+    }
+
     public function init(): void
     {
         $this->addTaskCommands();

src/Host/Host.php

@@ -28,10 +28,7 @@ class Host
 
     public function __construct(string $hostname)
     {
-        $parent = null;
-        if (Deployer::get()) {
-            $parent = Deployer::get()->config;
-        }
+        $parent = Deployer::get()->config;
         $this->config = new Configuration($parent);
         $this->set('#alias', $hostname);
         $this->set('hostname', preg_replace('/\/.+$/', '', $hostname));

tests/phpstan-baseline.neon

@@ -15,11 +15,6 @@ parameters:
 			count: 1
 			path: ../src/Command/BlackjackCommand.php
 
-		-
-			message: "#^If condition is always true\\.$#"
-			count: 1
-			path: ../src/Host/Host.php
-
 		-
 			message: "#^Unreachable statement \\- code above always terminates\\.$#"
 			count: 1

tests/src/Host/HostTest.php

@@ -8,10 +8,22 @@
 namespace Deployer\Host;
 
 use Deployer\Configuration;
+use Deployer\Deployer;
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Console\Application;
 
 class HostTest extends TestCase
 {
+    protected function setUp(): void
+    {
+        new Deployer(new Application());
+    }
+
+    protected function tearDown(): void
+    {
+        Deployer::resetInstance();
+    }
+
     public function testHost()
     {
         $host = new Host('host');

tests/src/Selector/SelectorTest.php

@@ -2,12 +2,24 @@
 
 namespace Deployer\Selector;
 
+use Deployer\Deployer;
 use Deployer\Host\Host;
 use Deployer\Host\HostCollection;
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Console\Application;
 
 class SelectorTest extends TestCase
 {
+    protected function setUp(): void
+    {
+        new Deployer(new Application());
+    }
+
+    protected function tearDown(): void
+    {
+        Deployer::resetInstance();
+    }
+
     public function testSelectHosts()
     {
         $prod = (new Host('prod.domain.com'))->set('labels', ['stage' => 'prod']);

tests/src/Task/TaskTest.php

@@ -7,8 +7,12 @@
 
 namespace Deployer\Task;
 
+use Deployer\Deployer;
 use Deployer\Host\Host;
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Input\Input;
+use Symfony\Component\Console\Output\Output;
 
 use function Deployer\invoke;
 use function Deployer\task;
@@ -20,9 +24,18 @@ public function callback(): void;
 
 class TaskTest extends TestCase
 {
+    protected function setUp(): void
+    {
+        $console = new Application();
+        $deployer = new Deployer($console);
+        $deployer['input'] = $this->createStub(Input::class);
+        $deployer['output'] = $this->createStub(Output::class);
+    }
+
     protected function tearDown(): void
     {
         StubTask::$runned = 0;
+        Deployer::resetInstance();
     }
 
     public function testTask()