Issue #3450532 by immaculatexavier, megachriz, joachim: Fixed MarkdownFilter...

Issue #3450532 by immaculatexavier, megachriz, joachim: Fixed MarkdownFilter should pass a string to FilterProcessResult to prevent crashes when combined with subsequent filters.

src/Plugin/Filter/FilterMarkdown.php

@@ -150,7 +150,8 @@ class FilterMarkdown extends FilterBase implements ContainerFactoryPluginInterfa
     // Only use the parser to process the text if it's not empty.
     if (!empty($text)) {
       $language = $langcode ? \Drupal::languageManager()->getLanguage($langcode) : NULL;
-      $text = $this->getParser()->parse($text, $language);
+      // Ensure that the parsed text is cast to a string.
+      $text = (string) $this->getParser()->parse($text, $language);
     }
     return new FilterProcessResult($text);
   }

tests/src/Unit/MarkdownUnitTestBase.php

+<?php
+
+namespace Drupal\Tests\markdown\Unit;
+
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * Base class for Markdown unit tests.
+ */
+abstract class MarkdownUnitTestBase extends UnitTestCase {
+}

tests/src/Unit/Plugin/Filter/FilterMarkdownTest.php

+<?php
+
+namespace Drupal\Tests\markdown\Unit;
+
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Config\ImmutableConfig;
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Core\Render\ElementInfoManagerInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\Tests\markdown\Unit\MarkdownUnitTestBase;
+use Drupal\filter\FilterProcessResult;
+use Drupal\filter\Plugin\FilterInterface;
+use Drupal\markdown\PluginManager\ParserManagerInterface;
+use Drupal\markdown\Plugin\Filter\FilterMarkdown;
+use Drupal\markdown\Plugin\Markdown\ParserInterface;
+use Drupal\markdown\Render\ParsedMarkdownInterface;
+use Prophecy\Argument;
+
+/**
+ * @coversDefaultClass \Drupal\markdown\Plugin\Filter\FilterMarkdown
+ * @group markdown
+ */
+class FilterMarkdownTest extends MarkdownUnitTestBase {
+
+  /**
+   * The Element Info Manager service.
+   *
+   * @var \Prophecy\Prophecy\ProphecyInterface|\Drupal\Core\Render\ElementInfoManagerInterface
+   */
+  protected $elementInfo;
+
+  /**
+   * The Markdown Parser Plugin Manager service.
+   *
+   * @var \Prophecy\Prophecy\ProphecyInterface|\Drupal\markdown\PluginManager\ParserManagerInterface
+   */
+  protected $parserManager;
+
+  /**
+   * The Markdown Parser Plugin Manager service.
+   *
+   * @var \Prophecy\Prophecy\ProphecyInterface|\Drupal\markdown\Plugin\Markdown\ParserInterface
+   */
+  protected $parser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $this->elementInfo = $this->prophesize(ElementInfoManagerInterface::class);
+    $this->parserManager = $this->prophesize(ParserManagerInterface::class);
+
+    $this->parser = $this->prophesize(ParserInterface::class);
+    $this->parser->getPluginId()
+      ->willReturn('foo');
+    $this->parser->parse(Argument::type('string'), NULL)
+      ->willReturn($this->createMock(ParsedMarkdownInterface::class));
+    $this->parser->getConfiguration()
+      ->willReturn([]);
+
+    $container = new ContainerBuilder();
+    $config_factory = $this->prophesize(ConfigFactoryInterface::class);
+    $config_factory->get('markdown.parser.foo')
+      ->willReturn($this->createMock(ImmutableConfig::class));
+    $container->set('config.factory', $config_factory->reveal());
+    \Drupal::setContainer($container);
+  }
+
+  /**
+   * Returns a new FilterMarkdown instance to test with.
+   *
+   * @param array $configuration
+   *   (optional) The configuration for the filter.
+   *
+   * @return \Drupal\markdown\Plugin\Filter\FilterMarkdown
+   *   A FilterMarkdown instance.
+   */
+  protected function getInstance(array $configuration = []): FilterMarkdown {
+    $plugin_definition = [
+      'description' => new TranslatableMarkup('Allows content to be submitted using Markdown, a simple plain-text syntax that is filtered into valid HTML.'),
+      'weight' => -15,
+      'status' => TRUE,
+      'settings' => [],
+      'id' => 'markdown',
+      'title' => new TranslatableMarkup('Markdown'),
+      'type' => FilterInterface::TYPE_MARKUP_LANGUAGE,
+      'class' => FilterMarkdown::class,
+      'provider' => 'markdown',
+    ];
+    return new FilterMarkdown($configuration, 'markdown', $plugin_definition, $this->elementInfo->reveal(), $this->parserManager->reveal());
+  }
+
+  /**
+   * @covers ::process
+   */
+  public function testProcess() {
+    $this->parserManager->getDefaultParser()
+      ->willReturn($this->parser->reveal());
+    $this->parserManager->createInstance('foo', Argument::type('array'))
+      ->willReturn($this->parser->reveal());
+
+    $filter = $this->getInstance();
+    $result = $filter->process('foo');
+    $this->assertInstanceof(FilterProcessResult::class, $result);
+    $this->assertIsString($result->getProcessedText());
+  }
+
+}