feat: guard Deployer singleton before Host construction (#4189)

* feat: improve deployer singleton handling by accounting for uninitialized state

* dev(address-review): Deployer::get() already throws \RuntimeException('Deployer is not initialized.') when the singleton is missing, so the constructor now always uses the deployer config as the parent and relies on that throw (no separate if (!Deployer::hasInstance()) block needed

* dev(address-review): fix phpstan; old reported error no longer present due to refactoring

Author: m1rm

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()