Issue #3396696 by rob_pr, heddn: Type error in DomApplyStyles plugin when using CKEditor5

src/Plugin/migrate/process/DomApplyStyles.php

@@ -126,12 +126,21 @@ class DomApplyStyles extends DomProcessBase implements ContainerFactoryPluginInt
       $message = 'The "format" option must be a non-empty string.';
       throw new InvalidPluginDefinitionException($this->getPluginId(), $message);
     }
-    $editor_styles = $this->configFactory
-      ->get("editor.editor.$format")
-      ->get('settings.plugins.stylescombo.styles');
-    foreach (explode("\r\n", $editor_styles) as $rule) {
-      if (preg_match('/(.*)\|(.*)/', $rule, $matches)) {
-        $this->styles[$matches[2]] = $matches[1];
+    $editor_config = $this->configFactory->get("editor.editor.$format");
+    if ($editor_config->get('editor') === 'ckeditor') {
+      $editor_styles = $editor_config->get('settings.plugins.stylescombo.styles') ?? '';
+      foreach (explode("\r\n", $editor_styles) as $rule) {
+        if (preg_match('/(.*)\|(.*)/', $rule, $matches)) {
+          $this->styles[$matches[2]] = $matches[1];
+        }
+      }
+    }
+    else if ($editor_config->get('editor') === 'ckeditor5') {
+      $editor_styles = $editor_config->get('settings.plugins.ckeditor5_style.styles') ?? [];
+      foreach ($editor_styles as $editor_style) {
+        if (preg_match('/<(.*) class="(.*)">/', $editor_style['element'], $matches)) {
+          $this->styles[$editor_style['label']] = $matches[1] . '.' . $matches[2];
+        }
       }
     }
   }

tests/src/Unit/process/DomApplyStylesTest.php

@@ -51,6 +51,9 @@ final class DomApplyStylesTest extends MigrateProcessTestCase {
   protected function setUp(): void {
     // Mock a config object.
     $prophecy = $this->prophesize(ImmutableConfig::class);
+    $prophecy
+      ->get('editor')
+      ->willReturn('ckeditor');
     $prophecy
       ->get('settings.plugins.stylescombo.styles')
       ->willReturn("strong.foo|Bold\r\nem.foo.bar|Italic\r\n");