[ErrorRenderer] Add DebugCommand for easy debugging and testing

src/Symfony/Bundle/FrameworkBundle/Resources/config/console.xml

@@ -194,5 +194,11 @@
             <argument type="service" id="debug.file_link_formatter" on-invalid="null" />
             <tag name="console.command" command="debug:form" />
         </service>
+
+        <service id="console.command.error_renderer_debug" class="Symfony\Component\ErrorRenderer\Command\DebugCommand">
+            <argument type="collection" /> <!-- All error renderers are injected here by ErrorRendererPass -->
+            <argument type="service" id="debug.file_link_formatter" on-invalid="null" />
+            <tag name="console.command" command="debug:error-renderer" />
+        </service>
     </services>
 </container>

src/Symfony/Component/ErrorRenderer/Command/DebugCommand.php

@@ -0,0 +1,123 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ErrorRenderer\Command;
+
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Exception\InvalidArgumentException;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Style\SymfonyStyle;
+use Symfony\Component\ErrorRenderer\ErrorRenderer\ErrorRendererInterface;
+use Symfony\Component\ErrorRenderer\Exception\FlattenException;
+use Symfony\Component\HttpKernel\Debug\FileLinkFormatter;
+
+/**
+ * A console command for retrieving information about error renderers.
+ *
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ *
+ * @internal
+ */
+class DebugCommand extends Command
+{
+    protected static $defaultName = 'debug:error-renderer';
+
+    private $renderers;
+    private $fileLinkFormatter;
+
+    /**
+     * @param ErrorRendererInterface[] $renderers
+     */
+    public function __construct(array $renderers, FileLinkFormatter $fileLinkFormatter = null)
+    {
+        $this->renderers = $renderers;
+        $this->fileLinkFormatter = $fileLinkFormatter;
+
+        parent::__construct();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function configure(): void
+    {
+        $this
+            ->addArgument('format', InputArgument::OPTIONAL, sprintf('Outputs a sample in a specific format (one of %s)', implode(', ', array_keys($this->renderers))))
+            ->setDescription('Displays all available error renderers and their formats.')
+            ->setHelp(<<<'EOF'
+The <info>%command.name%</info> command displays all available error renderers and
+their formats:
+
+  <info>php %command.full_name%</info>
+
+Or output a sample in a specific format:
+
+  <info>php %command.full_name% json</info>
+
+EOF
+            )
+        ;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        $io = new SymfonyStyle($input, $output);
+        $renderers = $this->renderers;
+
+        if ($format = $input->getArgument('format')) {
+            if (!isset($renderers[$format])) {
+                throw new InvalidArgumentException(sprintf('No error renderer found for format "%s". Known format are %s.', $format, implode(', ', array_keys($this->renderers))));
+            }
+
+            $exception = FlattenException::createFromThrowable(new \Exception('This is a sample exception.'), 500, ['X-Debug' => false]);
+            $io->writeln($renderers[$format]->render($exception));
+        } else {
+            $tableRows = [];
+            foreach ($renderers as $format => $renderer) {
+                $tableRows[] = [sprintf('<fg=cyan>%s</fg=cyan>', $format), $this->formatClassLink(\get_class($renderer))];
+            }
+
+            $io->title('Error Renderers');
+            $io->text('The following error renderers are available:');
+            $io->newLine();
+            $io->table(['Format', 'Class'], $tableRows);
+        }
+    }
+
+    private function formatClassLink(string $class): string
+    {
+        if ('' === $fileLink = $this->getFileLink($class)) {
+            return $class;
+        }
+
+        return sprintf('<href=%s>%s</>', $fileLink, $class);
+    }
+
+    private function getFileLink(string $class): string
+    {
+        if (null === $this->fileLinkFormatter) {
+            return '';
+        }
+
+        try {
+            $r = new \ReflectionClass($class);
+        } catch (\ReflectionException $e) {
+            return '';
+        }
+
+        return $this->fileLinkFormatter->format($r->getFileName(), $r->getStartLine());
+    }
+}

src/Symfony/Component/ErrorRenderer/DependencyInjection/ErrorRendererPass.php

@@ -24,11 +24,13 @@ class ErrorRendererPass implements CompilerPassInterface
 {
     private $rendererService;
     private $rendererTag;
+    private $debugCommandService;
 
-    public function __construct(string $rendererService = 'error_renderer', string $rendererTag = 'error_renderer.renderer')
+    public function __construct(string $rendererService = 'error_renderer', string $rendererTag = 'error_renderer.renderer', string $debugCommandService = 'console.command.error_renderer_debug')
     {
         $this->rendererService = $rendererService;
         $this->rendererTag = $rendererTag;
+        $this->debugCommandService = $debugCommandService;
     }
 
     /**
@@ -61,5 +63,9 @@ class ErrorRendererPass implements CompilerPassInterface
 
         $definition = $container->getDefinition($this->rendererService);
         $definition->replaceArgument(0, ServiceLocatorTagPass::register($container, $renderers));
+
+        if ($container->hasDefinition($this->debugCommandService)) {
+            $container->getDefinition($this->debugCommandService)->replaceArgument(0, $renderers);
+        }
     }
 }

src/Symfony/Component/ErrorRenderer/Tests/Command/DebugCommandTest.php

@@ -0,0 +1,90 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ErrorRenderer\Tests\Command;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Tester\CommandTester;
+use Symfony\Component\ErrorRenderer\Command\DebugCommand;
+use Symfony\Component\ErrorRenderer\ErrorRenderer\JsonErrorRenderer;
+use Symfony\Component\ErrorRenderer\ErrorRenderer\TxtErrorRenderer;
+use Symfony\Component\ErrorRenderer\ErrorRenderer\XmlErrorRenderer;
+
+class DebugCommandTest extends TestCase
+{
+    public function testAvailableRenderers()
+    {
+        $tester = $this->createCommandTester();
+        $ret = $tester->execute([], ['decorated' => false]);
+
+        $this->assertEquals(0, $ret, 'Returns 0 in case of success');
+        $this->assertSame(<<<TXT
+
+Error Renderers
+===============
+
+ The following error renderers are available:
+
+ -------- ----------------------------------------------------------------- 
+  Format   Class                                                            
+ -------- ----------------------------------------------------------------- 
+  json     Symfony\Component\ErrorRenderer\ErrorRenderer\JsonErrorRenderer  
+  xml      Symfony\Component\ErrorRenderer\ErrorRenderer\XmlErrorRenderer   
+  txt      Symfony\Component\ErrorRenderer\ErrorRenderer\TxtErrorRenderer   
+ -------- ----------------------------------------------------------------- 
+
+
+TXT
+            , $tester->getDisplay(true));
+    }
+
+    public function testFormatArgument()
+    {
+        $tester = $this->createCommandTester();
+        $ret = $tester->execute(['format' => 'json'], ['decorated' => false]);
+
+        $this->assertEquals(0, $ret, 'Returns 0 in case of success');
+        $this->assertSame(<<<TXT
+{
+    "title": "Internal Server Error",
+    "status": 500,
+    "detail": "This is a sample exception."
+}
+
+TXT
+            , $tester->getDisplay(true));
+    }
+
+    private function createCommandTester()
+    {
+        $command = new DebugCommand([
+            'json' => new JsonErrorRenderer(false),
+            'xml' => new XmlErrorRenderer(false),
+            'txt' => new TxtErrorRenderer(false),
+        ]);
+
+        $application = new Application();
+        $application->add($command);
+
+        return new CommandTester($application->find('debug:error-renderer'));
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Console\Exception\InvalidArgumentException
+     * @expectedExceptionMessage No error renderer found for format "foo". Known format are json, xml, txt.
+     */
+    public function testInvalidFormat()
+    {
+        $tester = $this->createCommandTester();
+        $tester->execute(['format' => 'foo'], ['decorated' => false]);
+    }
+}

src/Symfony/Component/ErrorRenderer/composer.json

@@ -20,6 +20,7 @@
         "psr/log": "~1.0"
     },
     "require-dev": {
+        "symfony/console": "^4.4",
         "symfony/dependency-injection": "^4.4",
         "symfony/http-kernel": "^4.4"
     },