Issue #3315698 by AdamPS: Improve back-compatibility, call hook_mail_alter()

modules/symfony_mailer_bc/symfony_mailer_bc.api.php

-<?php
-
-/**
- * @file
- * Documentation of Symfony Mailer back-compatibility hooks.
- */
-
-/**
- * Alters back-compatibility creation of an email.
- *
- * The parameters supplied are from the old mail manager interface. The altered
- * values will be passed to the email factory.
- *
- * @param array $message
- *   A message array, as described in hook_mail_alter().
- * @param \Drupal\Core\Config\Entity\ConfigEntityInterface|null $entity
- *   (optional) Entity. @see \Drupal\symfony_mailer\EmailInterface::getEntity()
- *
- * @see \Drupal\Core\Mail\MailManagerInterface::mail()
- * @see \Drupal\symfony_mailer\EmailFactory
- */
-function hook_mailer_bc_alter(array &$message, ?ConfigEntityInterface $entity) {
-}
-
-/**
- * Alters back-compatibility creation of an email from a specific module.
- *
- * @param array $message
- *   A message array, as described in hook_mail_alter().
- * @param \Drupal\Core\Config\Entity\ConfigEntityInterface|null $entity
- *   (optional) Entity. @see \Drupal\symfony_mailer\EmailInterface::getEntity()
- */
-function hook_mailer_bc_MODULE_alter(array &$message, ?ConfigEntityInterface $entity) {
-}

modules/symfony_mailer_bc/symfony_mailer_bc.info.yml

-name: Symfony Mailer Back-compatibility
+name: Symfony Mailer Override
 type: module
-description: 'Back-compatibility mapper for Symfony Mailer. Entirely replaces the default mail system, so that all Drupal emails will be sent via Symfony Mailer.'
+description: 'Overrides email building for key core and contrib modules, improving features and integration with Symfony Mailer.'
 core_version_requirement: ^9.1
 package: Mail
 dependencies:

modules/symfony_mailer_bc/symfony_mailer_bc.install

-<?php
-
-/**
- * @file
- * Install, functions for the Symfony Mailer Back-compatibility module.
- */
-
-/**
- * Implements hook_requirements().
- */
-function symfony_mailer_bc_requirements($phase) {
-  $requirements = [];
-  if ($phase === 'install') {
-    if (\Drupal::moduleHandler()->moduleExists('mailsystem')) {
-      $requirements['symfony_mailer_bc'] = [
-        'description' => t('Symfony Mailer Back-compatibility module cannot be installed because the Mail System module is installed and incompatible.'),
-        'severity' => REQUIREMENT_ERROR,
-      ];
-    }
-  }
-  return $requirements;
-}

modules/symfony_mailer_bc/symfony_mailer_bc.module

@@ -6,7 +6,6 @@
  */
 
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\symfony_mailer\Annotation\EmailBuilder;
 
 /**
  * Implements hook_theme().
@@ -22,28 +21,6 @@ function symfony_mailer_bc_theme($existing, $type, $theme, $path) {
   return $hooks;
 }
 
-/**
- * Implements hook_mailer_builder_info_alter().
- */
-function symfony_mailer_bc_mailer_builder_info_alter(array &$email_builders) {
-  // Add EmailBuilder definitions for any implementations of hook_mail() that
-  // don't already have one, using LegacyEmailBuilder.
-  $module_handler = \Drupal::moduleHandler();
-  $mail_hooks = $module_handler->getImplementations('mail');
-  $missing = array_diff($mail_hooks, array_keys($email_builders));
-
-  foreach ($missing as $type) {
-    $params = [
-      'id' => $type,
-      'label' => $module_handler->getName($type),
-      'class' => "Drupal\symfony_mailer_bc\Plugin\EmailBuilder\LegacyEmailBuilder",
-      'provider' => $type,
-    ];
-
-    $email_builders[$type] = (new EmailBuilder($params))->get();
-  }
-}
-
 /**
  * Implements hook_module_implements_alter().
  */

src/BaseEmailTrait.php

@@ -56,7 +56,8 @@ trait BaseEmailTrait {
    */
   public function setAddress(string $name, $addresses) {
     assert(isset($this->addresses[$name]));
-    if ($name == 'To') {
+    // See Mailer::doSend() for explanation of __disable_customize__.
+    if (($name == 'To') && !$this->getParam('__disable_customize__')) {
       $this->valid(self::PHASE_BUILD);
     }
     $this->addresses[$name] = Address::convert($addresses);

src/LegacyMailerHelper.php

+<?php
+
+namespace Drupal\symfony_mailer;
+
+use Drupal\Component\Render\MarkupInterface;
+
+/**
+ * Provides the legacy mailer helper service.
+ */
+class LegacyMailerHelper implements LegacyMailerHelperInterface {
+
+  /**
+   * List of headers for conversion to array.
+   *
+   * @var array
+   */
+  protected const HEADERS = [
+    'From' => 'from',
+    'Reply-To' => 'reply-to',
+    'To' => 'to',
+    'Cc' => 'cc',
+    'Bcc' => 'bcc',
+  ];
+
+  /**
+   * The mailer helper.
+   *
+   * @var \Drupal\symfony_mailer\MailerHelperInterface
+   */
+  protected $mailerHelper;
+
+  /**
+   * Constructs the MailerHelper object.
+   *
+   * @param \Drupal\symfony_mailer\MailerHelperInterface $mailer_helper
+   *   The mailer helper.
+   */
+  public function __construct(MailerHelperInterface $mailer_helper) {
+    $this->mailerHelper = $mailer_helper;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function formatBody(array $body_array) {
+    foreach ($body_array as $part) {
+      if ($part instanceof MarkupInterface) {
+        $body[] = ['#markup' => $part];
+      }
+      else {
+        $body[] = [
+          '#type' => 'processed_text',
+          '#text' => $part,
+        ];
+      }
+    }
+    return $body ?? [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function emailToArray(EmailInterface $email, array $message) {
+    $message['subject'] = $email->getSubject();
+    if ($email->getPhase() >= EmailInterface::PHASE_POST_RENDER) {
+      $message['body'] = $email->getHtmlBody();
+    }
+
+    $headers = $email->getHeaders();
+    foreach (self::HEADERS as $name => $key) {
+      if ($headers->has($name)) {
+        $message['headers'][$name] = $headers->get($name)->getBodyAsString();
+      }
+      if ($key) {
+        $message[$key] = $message['headers'][$name] ?? NULL;
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function emailFromArray(EmailInterface $email, array $message) {
+    $email->setSubject($message['subject']);
+
+    // Attachments.
+    $attachments = $message['params']['attachments'] ?? [];
+    foreach ($attachments as $attachment) {
+      $email->attachFromPath($attachment['filepath'], $attachment['filename'] ?? NULL, $attachment['filemime'] ?? NULL);
+    }
+
+    // Address headers.
+    foreach (self::HEADERS as $name => $key) {
+      $encoded = $message['headers'][$name] ?? $message[$key] ?? NULL;
+      if (isset($encoded)) {
+        $email->setAddress($name, $this->mailerHelper->parseAddress($encoded));
+      }
+    }
+  }
+
+}

src/LegacyMailerHelperInterface.php

+<?php
+
+namespace Drupal\symfony_mailer;
+
+/**
+ * Provides the legacy mailer helper service.
+ */
+interface LegacyMailerHelperInterface {
+
+  /**
+   * Formats a message body.
+   *
+   * Performs conversion of the message body as required by
+   * \Drupal\Core\Mail\MailInterface::format().
+   *
+   * @param array $body_array
+   *   An array of body parts.
+   *
+   * @return string
+   *   The body as a single formatted string.
+   */
+  public function formatBody(array $body_array);
+
+  /**
+   * Fills a message array from an Email.
+   *
+   * @param \Drupal\symfony_mailer\EmailInterface $email
+   *   The email to fill from.
+   * @param array $message
+   *   The array to fill.
+   */
+  public function emailToArray(EmailInterface $email, array $message);
+
+  /**
+   * Fills an Email from a message array.
+   *
+   * @param \Drupal\symfony_mailer\EmailInterface $email
+   *   The email to fill.
+   * @param array $message
+   *   The array to fill from.
+   */
+  public function emailFromArray(EmailInterface $email, array $message);
+
+}

modules/symfony_mailer_bc/src/MailManagerReplacement.php → src/MailManagerReplacement.php

 <?php
 
-namespace Drupal\symfony_mailer_bc;
+namespace Drupal\symfony_mailer;
 
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
@@ -9,8 +9,6 @@ use Drupal\Core\Logger\LoggerChannelFactoryInterface;
 use Drupal\Core\Mail\MailManager;
 use Drupal\Core\Render\RendererInterface;
 use Drupal\Core\StringTranslation\TranslationInterface;
-use Drupal\symfony_mailer\EmailFactoryInterface;
-use Drupal\symfony_mailer\EmailInterface;
 use Drupal\symfony_mailer\Processor\EmailBuilderManagerInterface;
 
 /**
@@ -18,19 +16,6 @@ use Drupal\symfony_mailer\Processor\EmailBuilderManagerInterface;
  */
 class MailManagerReplacement extends MailManager implements MailManagerReplacementInterface {
 
-  /**
-   * List of headers for conversion to array.
-   *
-   * @var array
-   */
-  protected const HEADERS = [
-    'From' => 'from',
-    'Reply-To' => 'reply-to',
-    'To' => 'to',
-    'Cc' => 'cc',
-    'Bcc' => 'bcc',
-  ];
-
   /**
    * The email factory.
    *
@@ -45,6 +30,13 @@ class MailManagerReplacement extends MailManager implements MailManagerReplaceme
    */
   protected $emailBuilderManager;
 
+  /**
+   * The legacy mailer helper.
+   *
+   * @var \Drupal\symfony_mailer\LegacyMailerHelperInterface
+   */
+  protected $legacyHelper;
+
   /**
    * Constructs the MailManagerReplacement object.
    *
@@ -67,11 +59,14 @@ class MailManagerReplacement extends MailManager implements MailManagerReplaceme
    *   The email factory.
    * @param \Drupal\symfony_mailer\Processor\EmailBuilderManagerInterface $email_builder_manager
    *   The email builder manager.
+   * @param \Drupal\symfony_mailer\LegacyMailerHelperInterface $legacy_helper
+   *   The legacy mailer helper.
    */
-  public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler, ConfigFactoryInterface $config_factory, LoggerChannelFactoryInterface $logger_factory, TranslationInterface $string_translation, RendererInterface $renderer, EmailFactoryInterface $email_factory, EmailBuilderManagerInterface $email_builder_manager) {
+  public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler, ConfigFactoryInterface $config_factory, LoggerChannelFactoryInterface $logger_factory, TranslationInterface $string_translation, RendererInterface $renderer, EmailFactoryInterface $email_factory, EmailBuilderManagerInterface $email_builder_manager, LegacyMailerHelperInterface $legacy_helper) {
     parent::__construct($namespaces, $cache_backend, $module_handler, $config_factory, $logger_factory, $string_translation, $renderer);
     $this->emailFactory = $email_factory;
     $this->emailBuilderManager = $email_builder_manager;
+    $this->legacyHelper = $legacy_helper;
   }
 
   /**
@@ -91,26 +86,17 @@ class MailManagerReplacement extends MailManager implements MailManagerReplaceme
 
     // Create an email from the array. Always call the plug-in from the module
     // name, not any variants.
-    $email = $this->emailBuilderManager->createInstance($module)->fromArray($this->emailFactory, $message);
+    $email = $this->emailBuilderManager->createInstance($message['module'])->fromArray($this->emailFactory, $message);
 
     if ($send) {
       $message['result'] = $email->send();
     }
-
-    // Update the message array.
-    $message['subject'] = $email->getSubject();
-    $message['body'] = ($email->getPhase() >= EmailInterface::PHASE_POST_RENDER) ? $email->getHtmlBody() : $email->getBody();
-
-    $headers = $email->getHeaders();
-    foreach (self::HEADERS as $name => $key) {
-      if ($headers->has($name)) {
-        $message['headers'][$name] = $headers->get($name)->getBodyAsString();
-      }
-      if ($key) {
-        $message[$key] = $message['headers'][$name] ?? NULL;
-      }
+    else {
+      // We set 'result' to NULL, because FALSE indicates an error in sending.
+      $message['result'] = NULL;
     }
 
+    $this->legacyHelper->emailToArray($email, $message);
     return $message;
   }
 

modules/symfony_mailer_bc/src/MailManagerReplacementInterface.php → src/MailManagerReplacementInterface.php

 <?php
 
-namespace Drupal\symfony_mailer_bc;
+namespace Drupal\symfony_mailer;
 
 use Drupal\Core\Mail\MailManagerInterface;
 

src/Mailer.php

@@ -173,19 +173,35 @@ class Mailer implements MailerInterface {
       $this->changeTheme($theme_name);
     }
 
-    // Determine langcode and account from the to address, if there is
-    // agreement.
-    $langcodes = $accounts = [];
-    foreach ($email->getTo() as $to) {
-      if ($loop_langcode = $to->getLangcode()) {
-        $langcodes[$loop_langcode] = $loop_langcode;
-      }
-      if ($loop_account = $to->getAccount()) {
-        $accounts[$loop_account->id()] = $loop_account;
+    $current_langcode = $this->languageManager->getCurrentLanguage()->getId();
+    if ($email->getParam('__disable_customize__')) {
+      // Undocumented setting for use from LegacyEmailBuilder only for
+      // back-compatibility. This may change without notice.
+      //
+      // By default, the language code and account are customized based on the
+      // recipient ('To' address). This setting disables customization, and
+      // leaves the language and account unchanged. Normally this is a bad idea
+      // and it can even expose private information from rendering an entity in
+      // the context of a privileged user.
+      $langcode = $current_langcode;
+      $account = $this->account;
+    }
+    else {
+      // Determine langcode and account from the to address, if there is
+      // agreement.
+      $langcodes = $accounts = [];
+      foreach ($email->getTo() as $to) {
+        if ($loop_langcode = $to->getLangcode()) {
+          $langcodes[$loop_langcode] = $loop_langcode;
+        }
+        if ($loop_account = $to->getAccount()) {
+          $accounts[$loop_account->id()] = $loop_account;
+        }
       }
+      $langcode = (count($langcodes) == 1) ? reset($langcodes) : $this->languageManager->getDefaultLanguage()->getId();
+      $account = (count($accounts) == 1) ? reset($accounts) : User::getAnonymousUser();
     }
-    $langcode = (count($langcodes) == 1) ? reset($langcodes) : $this->languageManager->getDefaultLanguage()->getId();
-    $account = (count($accounts) == 1) ? reset($accounts) : User::getAnonymousUser();
+
     $email->customize($langcode, $account);
 
     $must_switch_account = $account->id() != $this->account->id();
@@ -194,7 +210,6 @@ class Mailer implements MailerInterface {
       $this->accountSwitcher->switchTo($account);
     }
 
-    $current_langcode = $this->languageManager->getCurrentLanguage()->getId();
     $must_switch_language = $langcode !== $current_langcode;
 
     if ($must_switch_language) {

modules/symfony_mailer_bc/src/Plugin/EmailBuilder/LegacyEmailBuilder.php → src/Plugin/EmailBuilder/LegacyEmailBuilder.php

 <?php
 
-namespace Drupal\symfony_mailer_bc\Plugin\EmailBuilder;
+namespace Drupal\symfony_mailer\Plugin\EmailBuilder;
 
-use Drupal\Component\Render\MarkupInterface;
+use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\symfony_mailer\EmailFactoryInterface;
 use Drupal\symfony_mailer\EmailInterface;
 use Drupal\symfony_mailer\Exception\SkipMailException;
-use Drupal\symfony_mailer\MailerHelperInterface;
+use Drupal\symfony_mailer\LegacyMailerHelperInterface;
 use Drupal\symfony_mailer\Processor\EmailBuilderBase;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
- * Defines the Legacy Email Builder plug-in that calls hook_mail().
+ * Defines the Legacy Email Builder plug-in that uses a message array.
  */
 class LegacyEmailBuilder extends EmailBuilderBase implements ContainerFactoryPluginInterface {
 
   /**
-   * The mailer helper.
+   * The legacy mailer helper.
    *
-   * @var \Drupal\symfony_mailer\MailerHelperInterface
+   * @var \Drupal\symfony_mailer\LegacyMailerHelperInterface
    */
-  protected $mailerHelper;
+  protected $legacyHelper;
 
   /**
-   * List of headers for conversion from array.
+   * The module handler.
    *
-   * We omitted the To header, since it needs to be set in the build phase.
-   *
-   * @var array
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
    */
-  protected const HEADERS = [
-    'From' => 'from',
-    'Reply-To' => 'reply-to',
-    'Cc' => 'cc',
-    'Bcc' => 'bcc',
-  ];
+  protected $moduleHandler;
 
   /**
    * Constructor.
@@ -46,12 +39,15 @@ class LegacyEmailBuilder extends EmailBuilderBase implements ContainerFactoryPlu
    *   The plugin ID for the plugin instance.
    * @param mixed $plugin_definition
    *   The plugin implementation definition.
-   * @param \Drupal\symfony_mailer\MailerHelperInterface $mailer_helper
-   *   The mailer helper.
+   * @param \Drupal\symfony_mailer\LegacyMailerHelperInterface $legacy_helper
+   *   The legacy mailer helper.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler to invoke the alter hook with.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, MailerHelperInterface $mailer_helper) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, LegacyMailerHelperInterface $legacy_helper, ModuleHandlerInterface $module_handler) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
-    $this->mailerHelper = $mailer_helper;
+    $this->legacyHelper = $legacy_helper;
+    $this->moduleHandler = $module_handler;
   }
 
   /**
@@ -62,7 +58,8 @@ class LegacyEmailBuilder extends EmailBuilderBase implements ContainerFactoryPlu
       $configuration,
       $plugin_id,
       $plugin_definition,
-      $container->get('symfony_mailer.helper')
+      $container->get('symfony_mailer.legacy_helper'),
+      $container->get('module_handler'),
     );
   }
 
@@ -78,18 +75,8 @@ class LegacyEmailBuilder extends EmailBuilderBase implements ContainerFactoryPlu
    */
   public function createParams(EmailInterface $email, array $legacy_message = NULL) {
     assert($legacy_message != NULL);
-    $email->setParam('legacy_message', $legacy_message);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function build(EmailInterface $email) {
-    $message = $email->getParam('legacy_message');
-    $recipient = $message['to'] ?? NULL;
-    if (isset($recipient)) {
-      $email->setTo($this->mailerHelper->parseAddress($recipient, $message['langcode']));
-    }
+    $email->setParam('legacy_message', $legacy_message)
+      ->setParam('__disable_customize__', TRUE);
   }
 
   /**
@@ -103,57 +90,21 @@ class LegacyEmailBuilder extends EmailBuilderBase implements ContainerFactoryPlu
       'headers' => [],
     ];
 
-    // Call hook_mail() on this module.
-    if (function_exists($function = $message['module'] . '_mail')) {
-      $function($message['key'], $message, $message['params']);
-    }
+    // Build the email by invoking hook_mail() on this module.
+    $args = [$message['key'], &$message, $message['params']];
+    $this->moduleHandler->invoke($message['module'], 'mail', $args);
 
-    if (isset($message['send']) && !$message['send']) {
-      throw new SkipMailException('Send aborted by hook_mail().');
-    }
+    // Invoke hook_mail_alter() to allow all modules to alter the resulting
+    // email.
+    $this->moduleHandler->alter('mail', $message);
 
-    $this->emailFromArray($email, $message);
-  }
-
-  /**
-   * Fills an Email from a message array.
-   *
-   * @param \Drupal\symfony_mailer\EmailInterface $email
-   *   The email to fill.
-   * @param array $message
-   *   The array to fill from.
-   */
-  protected function emailFromArray(EmailInterface $email, array $message) {
-    $email->setSubject($message['subject']);
-
-    // Add attachments.
-    $attachments = $message['params']['attachments'] ?? [];
-    foreach ($attachments as $attachment) {
-      $email->attachFromPath($attachment['filepath'], $attachment['filename'] ?? NULL, $attachment['filemime'] ?? NULL);
-    }
-
-    // Add Address headers from message array to Email object.
-    // The "To" header will be set via build().
-    foreach (self::HEADERS as $name => $key) {
-      $encoded = $message['headers'][$name] ?? $message[$key] ?? NULL;
-      if (isset($encoded)) {
-        $email->setAddress($name, $this->mailerHelper->parseAddress($encoded));
-      }
+    if (!$message['send']) {
+      throw new SkipMailException('Send aborted by hook_mail().');
     }
 
-    // Add the body to the Email object, as rendered by hook_mail.
-    foreach ($message['body'] as $part) {
-      if ($part instanceof MarkupInterface) {
-        $body[] = ['#markup' => $part];
-      }
-      else {
-        $body[] = [
-          '#type' => 'processed_text',
-          '#text' => $part,
-        ];
-      }
-    }
-    $email->setBody($body ?? []);
+    // Fill the email from the message array.
+    $email->setBody($this->legacyHelper->formatBody($message['body']));
+    $this->legacyHelper->emailFromArray($email, $message);
   }
 
 }

modules/symfony_mailer_bc/src/SymfonyMailerBcServiceProvider.php → src/SymfonyMailerServiceProvider.php

 <?php
 
-namespace Drupal\symfony_mailer_bc;
+namespace Drupal\symfony_mailer;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\DependencyInjection\ServiceProviderBase;
@@ -9,16 +9,19 @@ use Symfony\Component\DependencyInjection\Reference;
 /**
  * Modifies the mail manager service.
  */
-class SymfonyMailerBcServiceProvider extends ServiceProviderBase {
+class SymfonyMailerServiceProvider extends ServiceProviderBase {
 
   /**
    * {@inheritdoc}
    */
   public function alter(ContainerBuilder $container) {
     $definition = $container->getDefinition('plugin.manager.mail');
-    $definition->setClass('Drupal\symfony_mailer_bc\MailManagerReplacement')
+    // Cancel any method calls, for example from mailsystem.
+    $definition->setClass('Drupal\symfony_mailer\MailManagerReplacement')
       ->addArgument(new Reference('email_factory'))
-      ->addArgument(new Reference('plugin.manager.email_builder'));
+      ->addArgument(new Reference('plugin.manager.email_builder'))
+      ->addArgument(new Reference('symfony_mailer.legacy_helper'))
+      ->setMethodCalls([]);
   }
 
 }

symfony_mailer.module

@@ -7,6 +7,7 @@
 
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Url;
+use Drupal\symfony_mailer\Annotation\EmailBuilder;
 
 /**
  * Implements hook_theme().
@@ -29,6 +30,28 @@ function symfony_mailer_theme_suggestions_email(array $variables) {
   return array_slice($variables['email']->getSuggestions('email', '__'), 1);
 }
 
+/**
+ * Implements hook_mailer_builder_info_alter().
+ */
+function symfony_mailer_mailer_builder_info_alter(array &$email_builders) {
+  // Add EmailBuilder definitions for any implementations of hook_mail() that
+  // don't already have one, using LegacyEmailBuilder.
+  $module_handler = \Drupal::moduleHandler();
+  $mail_hooks = $module_handler->getImplementations('mail');
+  $missing = array_diff($mail_hooks, array_keys($email_builders));
+
+  foreach ($missing as $type) {
+    $params = [
+      'id' => $type,
+      'label' => $module_handler->getName($type),
+      'class' => "Drupal\symfony_mailer\Plugin\EmailBuilder\LegacyEmailBuilder",
+      'provider' => $type,
+    ];
+
+    $email_builders[$type] = (new EmailBuilder($params))->get();
+  }
+}
+
 /**
  * Prepares variables for email template.
  *

symfony_mailer.services.yml

@@ -18,3 +18,6 @@ services:
   symfony_mailer.helper:
     class: Drupal\symfony_mailer\MailerHelper
     arguments: ['@entity_type.manager', '@plugin.manager.email_adjuster', '@plugin.manager.email_builder', '@config.factory']
+  symfony_mailer.legacy_helper:
+    class: Drupal\symfony_mailer\LegacyMailerHelper
+    arguments: ['@symfony_mailer.helper']

modules/symfony_mailer_bc/tests/modules/symfony_mailer_bc_test/src/Form/BcTestMailForm.php → tests/modules/symfony_mailer_legacy_test/src/Form/LegacyTestEmailForm.php

 <?php
 
-namespace Drupal\symfony_mailer_bc_test\Form;
+namespace Drupal\symfony_mailer_legacy_test\Form;
 
 use Drupal\Core\Form\FormBase;
 use Drupal\Core\Form\FormStateInterface;
@@ -8,9 +8,9 @@ use Drupal\Core\Mail\MailManagerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
- * Test module form to send a test BC mail.
+ * Test module form to send a test legacy email.
  */
-class BcTestMailForm extends FormBase {
+class LegacyTestEmailForm extends FormBase {
 
   /**
    * The mail manager service.
@@ -42,7 +42,7 @@ class BcTestMailForm extends FormBase {
    * {@inheritdoc}
    */
   public function getFormId() {
-    return 'symfony_mailer_bc_test_form';
+    return 'symfony_mailer_legacy_test_form';
   }
 
   /**
@@ -52,7 +52,7 @@ class BcTestMailForm extends FormBase {
     $form = [];
     $form['submit'] = [
       '#type' => 'submit',
-      '#value' => 'Send test mail',
+      '#value' => 'Send test email',
     ];
     /** @var \Drupal\Core\Theme\ThemeManagerInterface $theme_manager */
     $theme_manager = \Drupal::service('theme.manager');
@@ -68,7 +68,7 @@ class BcTestMailForm extends FormBase {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
-    $this->mailManager->mail('symfony_mailer_bc_test', 'bc_test', 'test@example.com', 'en');
+    $this->mailManager->mail('symfony_mailer_legacy_test', 'legacy_test', 'test@example.com', 'en');
   }
 
 }

modules/symfony_mailer_bc/tests/modules/symfony_mailer_bc_test/symfony_mailer_bc_test.info.yml → tests/modules/symfony_mailer_legacy_test/symfony_mailer_legacy_test.info.yml

-name: Symfony Mailer BC Test
+name: Symfony Mailer Legacy Email Test
 type: module
 package: Mail
 hidden: true
 core_version_requirement: ^9.1
 dependencies:
   - symfony_mailer:symfony_mailer
-  - symfony_mailer:symfony_mailer_bc

modules/symfony_mailer_bc/tests/modules/symfony_mailer_bc_test/symfony_mailer_bc_test.module → tests/modules/symfony_mailer_legacy_test/symfony_mailer_legacy_test.module

@@ -2,35 +2,44 @@
 
 /**
  * @file
- * Hook implementations for the Symfony Mailer BC test module.
+ * Hook implementations for the Symfony Mailer Legacy Email test module.
  */
 
 /**
  * Implements hook_mail().
  */
-function symfony_mailer_bc_test_mail($key, &$message, $params) {
-  if ($key == 'bc_test') {
-    $message['subject'] = 'Backwards compatible mail sent via hook_mail().';
+function symfony_mailer_legacy_test_mail($key, &$message, $params) {
+  if ($key == 'legacy_test') {
+    $message['subject'] = 'Legacy email sent via hook_mail().';
     $message['body'][] = 'This email is sent via hook_mail().';
-    $message['body'][] = symfony_mailer_bc_test_add_template_to_body();
+    $message['body'][] = symfony_mailer_legacy_test_add_template_to_body();
     $message['headers']['Cc'] = 'cc@example.com';
   }
 }
 
+/**
+ * Implements hook_mail_alter().
+ */
+function symfony_mailer_legacy_test_mail_alter(&$message) {
+  if ($message['id'] == 'symfony_mailer_legacy_test_legacy_test') {
+    $message['body'][] = 'This email was altered via hook_mail_alter().';
+  }
+}
+
 /**
  * Adds a rendered (Twig) template file to the body of the test email message.
  *
  * This mimics the logic implemented in Drupal Commerce, when sending the
  * "commerce order receipt" mail.
  */
-function symfony_mailer_bc_test_add_template_to_body() {
+function symfony_mailer_legacy_test_add_template_to_body() {
   /** @var \Drupal\Core\Theme\ThemeManagerInterface $theme_manager */
   $theme_manager = \Drupal::service('theme.manager');
   /** @var \Drupal\Core\Render\RendererInterface $renderer */
   $renderer = \Drupal::service('renderer');
   $current_theme = $theme_manager->getActiveTheme()->getName();
   $template = [
-    '#theme' => 'bc_test_mail',
+    '#theme' => 'legacy_test_email',
     '#current_theme' => $current_theme,
   ];
   return $renderer->render($template);
@@ -39,9 +48,9 @@ function symfony_mailer_bc_test_add_template_to_body() {
 /**
  * Implements hook_theme().
  */
-function symfony_mailer_bc_test_theme() {
+function symfony_mailer_legacy_test_theme() {
   return [
-    'bc_test_mail' => [
+    'legacy_test_email' => [
       'variables' => ['current_theme' => NULL],
     ],
   ];

modules/symfony_mailer_bc/tests/modules/symfony_mailer_bc_test/symfony_mailer_bc_test.routing.yml → tests/modules/symfony_mailer_legacy_test/symfony_mailer_legacy_test.routing.yml

-symfony_mailer_bc_test.send:
-  path: '/admin/symfony_mailer_bc_test/send'
+symfony_mailer_legacy_test.send:
+  path: '/admin/symfony_mailer_legacy_test/send'
   defaults:
-    _form: 'Drupal\symfony_mailer_bc_test\Form\BcTestMailForm'
-    _title: 'Send BC test mail'
+    _form: 'Drupal\symfony_mailer_legacy_test\Form\LegacyTestEmailForm'
+    _title: 'Send legacy test email'
   requirements:
     _access: 'TRUE'
   options:

modules/symfony_mailer_bc/tests/modules/symfony_mailer_bc_test/templates/bc-test-mail.html.twig → tests/modules/symfony_mailer_legacy_test/templates/legacy-test-email.html.twig

-<strong>This is the default BC test mail template.</strong>
+<strong>This is the default legacy test email template.</strong>
 <p>Rendered in theme: {{ current_theme }}</p>

modules/symfony_mailer_bc/tests/src/Functional/TestBcMail.php → tests/src/Functional/TestLegacyEmail.php

 <?php
 
-namespace Drupal\Tests\symfony_mailer_bc\Functional;
-
-use Drupal\Tests\symfony_mailer\Functional\SymfonyMailerTestBase;
+namespace Drupal\Tests\symfony_mailer\Functional;
 
 /**
  * Test the Symfony Mailer Back-compatibility module.
  *
  * @group symfony_mailer
  */
-class TestBcMail extends SymfonyMailerTestBase {
+class TestLegacyEmail extends SymfonyMailerTestBase {
 
   /**
    * Modules to enable.
@@ -18,9 +16,8 @@ class TestBcMail extends SymfonyMailerTestBase {
    */
   protected static $modules = [
     'symfony_mailer',
-    'symfony_mailer_bc',
     'symfony_mailer_test',
-    'symfony_mailer_bc_test',
+    'symfony_mailer_legacy_test',
   ];
 
   /**
@@ -36,13 +33,13 @@ class TestBcMail extends SymfonyMailerTestBase {
   }
 
   /**
-   * Test sending a backwards compatible email rendered via hook_mail().
+   * Test sending a legacy email rendered via hook_mail().
    */
-  public function testSendBcMail() {
+  public function testSendLegacyEmail() {
     $this->drupalLogin($this->adminUser);
-    // Trigger sending a backwards compatible email via hook_mail().
-    $this->drupalGet('admin/symfony_mailer_bc_test/send');
-    $this->submitForm([], 'Send test mail');
+    // Trigger sending a legacy email via hook_mail().
+    $this->drupalGet('admin/symfony_mailer_legacy_test/send');
+    $this->submitForm([], 'Send test email');
     $this->readMail();
 
     // Check email recipients.
@@ -50,34 +47,36 @@ class TestBcMail extends SymfonyMailerTestBase {
     $this->assertCc('cc@example.com', '');
 
     // Check email contents.
-    $this->assertSubject("Backwards compatible mail sent via hook_mail().");
+    $this->assertSubject("Legacy email sent via hook_mail().");
     $this->assertBodyContains("This email is sent via hook_mail().");
-    $this->assertBodyContains("This is the default BC test mail template.");
+    $this->assertBodyContains("This email was altered via hook_mail_alter().");
+    $this->assertBodyContains("This is the default legacy test email template.");
     $this->assertBodyContains("Rendered in theme: stark");
   }
 
   /**
-   * Test sending a backwards compatible email with custom email body template.
+   * Test sending a legacy email with custom email body template.
    */
-  public function testSendBcMailWithTheme() {
+  public function testSendLegacyEmailWithTheme() {
     $this->drupalLogin($this->adminUser);
     // Switch the current default theme and admin theme, and test if template
     // renders in the default theme instead of the admin theme, even though the
     // admin theme is active when the mail gets triggered.
-    \Drupal::service('theme_installer')->install(['test_bc_mail_theme', 'stark']);
+    $themes = ['test_legacy_email_theme', 'stark'];
+    \Drupal::service('theme_installer')->install($themes);
     $this->config('system.theme')
-      ->set('default', 'test_bc_mail_theme')
+      ->set('default', 'test_legacy_email_theme')
       ->set('admin', 'stark')
       ->save();
 
     /** @var \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler */
     $theme_handler = $this->container->get('theme_handler');
-    $this->assertTrue($theme_handler->themeExists('test_bc_mail_theme'));
+    $this->assertTrue($theme_handler->themeExists('test_legacy_email_theme'));
 
-    // Trigger sending a backwards compatible email via hook_mail().
-    $this->drupalGet('admin/symfony_mailer_bc_test/send');
+    // Trigger sending a legacy email via hook_mail().
+    $this->drupalGet('admin/symfony_mailer_legacy_test/send');
     $this->assertSession()->pageTextContains('Current theme: stark');
-    $this->submitForm([], 'Send test mail');
+    $this->submitForm([], 'Send test email');
     $this->readMail();
 
     // Check email recipients.
@@ -85,10 +84,11 @@ class TestBcMail extends SymfonyMailerTestBase {
     $this->assertCc('cc@example.com', '');
 
     // Check email contents.
-    $this->assertSubject("Backwards compatible mail sent via hook_mail().");
+    $this->assertSubject("Legacy email sent via hook_mail().");
     $this->assertBodyContains("This email is sent via hook_mail().");
-    $this->assertBodyContains("This is the overridden BC test mail template.");
-    $this->assertBodyContains("Rendered in theme: test_bc_mail_theme");
+    $this->assertBodyContains("This email was altered via hook_mail_alter().");
+    $this->assertBodyContains("This is the overridden legacy test email template.");
+    $this->assertBodyContains("Rendered in theme: test_legacy_email_theme");
   }
 
 }