bug #38845 [Console] Register signal handling only for commands implemeting SignalableCommandInterface (lyrixx)

This PR was merged into the 5.x branch.

Discussion
----------

[Console] Register signal handling only for commands implemeting SignalableCommandInterface

| Q             | A
| ------------- | ---
| Branch?       | 5.x for features
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #38820
| License       | MIT
| Doc PR        |

---

Actually, it does not make sens to listen all signals for all commands.

This commit also add more tests for this part of code.

Commits
-------

37b1faec8c [Console] Register signal handling only for commands implemeting SignalableCommandInterface

src/Symfony/Component/Console/Application.php

@@ -286,23 +286,6 @@ class Application implements ResetInterface
             $command = $this->find($alternative);
         }
 
-        if ($this->dispatcher && $this->signalRegistry) {
-            foreach ($this->signalsToDispatchEvent as $signal) {
-                $event = new ConsoleSignalEvent($command, $input, $output, $signal);
-
-                $this->signalRegistry->register($signal, function ($signal, $hasNext) use ($event) {
-                    $this->dispatcher->dispatch($event, ConsoleEvents::SIGNAL);
-
-                    // No more handlers, we try to simulate PHP default behavior
-                    if (!$hasNext) {
-                        if (!\in_array($signal, [\SIGUSR1, \SIGUSR2], true)) {
-                            exit(0);
-                        }
-                    }
-                });
-            }
-        }
-
         $this->runningCommand = $command;
         $exitCode = $this->doRunCommand($command, $input, $output);
         $this->runningCommand = null;
@@ -961,6 +944,24 @@ class Application implements ResetInterface
             if (!$this->signalRegistry) {
                 throw new RuntimeException('Unable to subscribe to signal events. Make sure that the `pcntl` extension is installed and that "pcntl_*" functions are not disabled by your php.ini\'s "disable_functions" directive.');
             }
+
+            if ($this->dispatcher) {
+                foreach ($this->signalsToDispatchEvent as $signal) {
+                    $event = new ConsoleSignalEvent($command, $input, $output, $signal);
+
+                    $this->signalRegistry->register($signal, function ($signal, $hasNext) use ($event) {
+                        $this->dispatcher->dispatch($event, ConsoleEvents::SIGNAL);
+
+                        // No more handlers, we try to simulate PHP default behavior
+                        if (!$hasNext) {
+                            if (!\in_array($signal, [\SIGUSR1, \SIGUSR2], true)) {
+                                exit(0);
+                            }
+                        }
+                    });
+                }
+            }
+
             foreach ($command->getSubscribedSignals() as $signal) {
                 $this->signalRegistry->register($signal, [$command, 'handleSignal']);
             }

src/Symfony/Component/Console/Tests/ApplicationTest.php

@@ -14,6 +14,7 @@ namespace Symfony\Component\Console\Tests;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Console\Application;
 use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Command\SignalableCommandInterface;
 use Symfony\Component\Console\CommandLoader\FactoryCommandLoader;
 use Symfony\Component\Console\DependencyInjection\AddConsoleCommandPass;
 use Symfony\Component\Console\Event\ConsoleCommandEvent;
@@ -1808,6 +1809,39 @@ class ApplicationTest extends TestCase
         $app->setCommandLoader($loader);
         $app->get('test');
     }
+
+    /**
+     * @requires extension pcntl
+     */
+    public function testSignal()
+    {
+        $command = new SignableCommand();
+
+        $dispatcherCalled = false;
+        $dispatcher = new EventDispatcher();
+        $dispatcher->addListener('console.signal', function () use (&$dispatcherCalled) {
+            $dispatcherCalled = true;
+        });
+
+        $application = new Application();
+        $application->setAutoExit(false);
+        $application->setDispatcher($dispatcher);
+        $application->setSignalsToDispatchEvent(SIGALRM);
+        $application->add($command);
+
+        $this->assertFalse($command->signaled);
+        $this->assertFalse($dispatcherCalled);
+
+        $this->assertSame(0, $application->run(new ArrayInput(['signal'])));
+        $this->assertFalse($command->signaled);
+        $this->assertFalse($dispatcherCalled);
+
+        $command->loop = 100000;
+        pcntl_alarm(1);
+        $this->assertSame(1, $application->run(new ArrayInput(['signal'])));
+        $this->assertTrue($command->signaled);
+        $this->assertTrue($dispatcherCalled);
+    }
 }
 
 class CustomApplication extends Application
@@ -1865,3 +1899,33 @@ class DisabledCommand extends Command
         return false;
     }
 }
+
+class SignableCommand extends Command implements SignalableCommandInterface
+{
+    public $signaled = false;
+    public $loop = 100;
+
+    protected static $defaultName = 'signal';
+
+    public function getSubscribedSignals(): array
+    {
+        return [SIGALRM];
+    }
+
+    public function handleSignal(int $signal): void
+    {
+        $this->signaled = true;
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        for ($i = 0; $i < $this->loop; ++$i) {
+            usleep(100);
+            if ($this->signaled) {
+                return 1;
+            }
+        }
+
+        return 0;
+    }
+}