[6.2] MailTemplate should work with interface

administrator/components/com_config/src/Model/ApplicationModel.php

@@ -1215,7 +1215,7 @@ public function sendTestMail()
             [
                 // Replace the occurrences of "@" and "|" in the site name
                 'sitename' => str_replace(['@', '|'], '', $app->get('sitename')),
-                'method'   => Text::_('COM_CONFIG_SENDMAIL_METHOD_' . strtoupper($mail->Mailer)),
+                'method'   => Text::_('COM_CONFIG_SENDMAIL_METHOD_' . strtoupper($mail->Mailer ?? $input->get('mailer'))),
             ]
         );
         $mailer->addRecipient($user->email, $user->name);
@@ -1230,10 +1230,10 @@ public function sendTestMail()
         }
 
         if ($mailSent === true) {
-            $methodName = Text::_('COM_CONFIG_SENDMAIL_METHOD_' . strtoupper($mail->Mailer));
+            $methodName = Text::_('COM_CONFIG_SENDMAIL_METHOD_' . strtoupper($mail->Mailer ?? $input->get('mailer')));
 
-            // If JMail send the mail using PHP Mail as fallback.
-            if ($mail->Mailer !== $app->get('mailer')) {
+            // If Mail send the mail using PHP Mail as fallback.
+            if (($mail->Mailer ?? $app->get('mailer')) !== $app->get('mailer')) {
                 $app->enqueueMessage(Text::sprintf('COM_CONFIG_SENDMAIL_SUCCESS_FALLBACK', $user->email, $methodName), 'warning');
             } else {
                 $app->enqueueMessage(Text::sprintf('COM_CONFIG_SENDMAIL_SUCCESS', $user->email, $methodName), 'message');

libraries/src/Mail/FormatConfigurableMailerInterface.php

@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * Joomla! Content Management System
+ *
+ * @copyright  (C) 2026 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license    GNU General Public License version 2 or later; see LICENSE.txt
+ */
+
+namespace Joomla\CMS\Mail;
+
+// phpcs:disable PSR1.Files.SideEffects
+\defined('_JEXEC') or die;
+// phpcs:enable PSR1.Files.SideEffects
+
+/**
+ * Provides a common interface to send emails with HTML.
+ *
+ * @since  __DEPLOY_VERSION__
+ */
+interface FormatConfigurableMailerInterface
+{
+    /**
+    * Sets message type to HTML.
+    *
+    * @param   boolean  $ishtml  Boolean true or false.
+    *
+    * @return  FormatConfigurableMailerInterface  Returns this object for chaining.
+    *
+    * @since   __DEPLOY_VERSION__
+    */
+    public function isHtml($ishtml = true);
+}

libraries/src/Mail/Mail.php

@@ -25,7 +25,7 @@
  *
  * @since  1.7.0
  */
-class Mail extends PHPMailer implements MailerInterface
+class Mail extends PHPMailer implements MailerInterface, TransportConfigurableMailerInterface, FormatConfigurableMailerInterface
 {
     /**
      * Mail instances container.

libraries/src/Mail/MailTemplate.php

@@ -36,7 +36,7 @@ class MailTemplate
     /**
      * Mailer object to send the actual mail.
      *
-     * @var    \Joomla\CMS\Mail\Mail
+     * @var    MailerInterface
      * @since  4.0.0
      */
     protected $mailer;
@@ -117,14 +117,15 @@ class MailTemplate
      *
      * @since   4.0.0
      */
-    public function __construct($templateId, $language, ?Mail $mailer = null)
+    public function __construct($templateId, $language, ?MailerInterface $mailer = null)
     {
         $this->template_id = $templateId;
         $this->language    = $language;
 
         if ($mailer) {
             $this->mailer = $mailer;
         } else {
+            @trigger_error('Mailer must be set, this will not be caught anymore in 8.0.', E_USER_DEPRECATED);
             $this->mailer = Factory::getMailer();
         }
     }
@@ -274,7 +275,7 @@ public function send()
         $replyToName = $app->get('replytoname', '');
 
         if ((int) $config->get('alternative_mailconfig', 0) === 1 && (int) $params->get('alternative_mailconfig', 0) === 1) {
-            if ($this->mailer->Mailer === 'smtp' || $params->get('mailer') === 'smtp') {
+            if ($this->mailer instanceof TransportConfigurableMailerInterface && $params->get('mailer') === 'smtp') {
                 $smtpauth   = ($params->get('smtpauth', $app->get('smtpauth')) == 0) ? null : 1;
                 $smtpuser   = $params->get('smtpuser', $app->get('smtpuser'));
                 $smtppass   = $params->get('smtppass', $app->get('smtppass'));
@@ -284,15 +285,15 @@ public function send()
                 $this->mailer->useSmtp($smtpauth, $smtphost, $smtpuser, $smtppass, $smtpsecure, $smtpport);
             }
 
-            if ($params->get('mailer') === 'sendmail') {
-                $this->mailer->isSendmail();
+            if ($this->mailer instanceof TransportConfigurableMailerInterface && $params->get('mailer') === 'sendmail') {
+                $this->mailer->useSendmail('joomla');
             }
 
             $mailfrom = $params->get('mailfrom', $app->get('mailfrom'));
             $fromname = $params->get('fromname', $app->get('fromname'));
 
             if (MailHelper::isEmailAddress($mailfrom)) {
-                $this->mailer->setFrom(MailHelper::cleanLine($mailfrom), MailHelper::cleanLine($fromname), false);
+                $this->mailer->setSender(MailHelper::cleanLine($mailfrom), MailHelper::cleanLine($fromname));
             }
 
             $replyTo     = $params->get('replyto', $replyTo);
@@ -335,7 +336,9 @@ public function send()
         }
 
         if ($mailStyle === 'html' || $mailStyle === 'both') {
-            $this->mailer->isHtml(true);
+            if ($this->mailer instanceof FormatConfigurableMailerInterface) {
+                $this->mailer->isHtml(true);
+            }
 
             // If HTML body is empty try to convert the Plain template to html
             if (!$htmlBody) {
@@ -413,7 +416,7 @@ public function send()
                     break;
                 case 'to':
                 default:
-                    $this->mailer->addAddress($recipient->mail, $recipient->name);
+                    $this->mailer->addRecipient($recipient->mail, $recipient->name);
             }
         }
 
@@ -437,15 +440,29 @@ public function send()
             }
         }
 
+        $tmpAttachmentFiles = [];
         foreach ($this->attachments as $attachment) {
             if (is_file($attachment->file)) {
                 $this->mailer->addAttachment($attachment->file, $this->getAttachmentName($attachment->file, $attachment->name));
-            } else {
+            } elseif ($this->mailer instanceof Mail) {
                 $this->mailer->addStringAttachment($attachment->file, $attachment->name);
+            } else {
+                // If the mailer does not support string attachments, create a temporary file and attach it
+                $tmpFile = tempnam(JPATH_CACHE, 'mailattachment_');
+                if (file_put_contents($tmpFile, $attachment->file) !== false) {
+                    $this->mailer->addAttachment($tmpFile, $attachment->name);
+                    $tmpAttachmentFiles[] = $tmpFile;
+                }
             }
         }
 
-        return $this->mailer->Send();
+        $success = $this->mailer->send();
+
+        foreach ($tmpAttachmentFiles as $tmpFile) {
+            @unlink($tmpFile);
+        }
+
+        return $success;
     }
 
     /**

libraries/src/Mail/TransportConfigurableMailerInterface.php

@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * Joomla! Content Management System
+ *
+ * @copyright  (C) 2026 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license    GNU General Public License version 2 or later; see LICENSE.txt
+ */
+
+namespace Joomla\CMS\Mail;
+
+// phpcs:disable PSR1.Files.SideEffects
+\defined('_JEXEC') or die;
+// phpcs:enable PSR1.Files.SideEffects
+
+/**
+ * Provides a common interface to send emails through an SMTP or sendmail service.
+ *
+ * @since  __DEPLOY_VERSION__
+ */
+interface TransportConfigurableMailerInterface
+{
+    /**
+     * Use SMTP for sending the email.
+     *
+     * @param   string   $auth    SMTP Authentication [optional]
+     * @param   string   $host    SMTP Host [optional]
+     * @param   string   $user    SMTP Username [optional]
+     * @param   string   $pass    SMTP Password [optional]
+     * @param   string   $secure  Use secure methods
+     * @param   integer  $port    The SMTP port
+     *
+     * @return  boolean  True on success
+     *
+     * @since   __DEPLOY_VERSION__
+     */
+    public function useSmtp($auth = null, $host = null, $user = null, $pass = null, $secure = null, $port = 25);
+
+    /**
+     * Use sendmail for sending the email.
+     *
+     * @return  boolean  True on success
+     *
+     * @since   __DEPLOY_VERSION__
+     */
+    public function useSendmail($sendmail = null);
+}

plugins/system/tasknotification/services/provider.php

@@ -12,6 +12,7 @@
 
 use Joomla\CMS\Extension\PluginInterface;
 use Joomla\CMS\Factory;
+use Joomla\CMS\Mail\MailerFactoryInterface;
 use Joomla\CMS\Plugin\PluginHelper;
 use Joomla\CMS\User\UserFactoryInterface;
 use Joomla\Database\DatabaseInterface;
@@ -40,6 +41,7 @@ public function register(Container $container): void
                 $plugin->setApplication(Factory::getApplication());
                 $plugin->setDatabase($container->get(DatabaseInterface::class));
                 $plugin->setUserFactory($container->get(UserFactoryInterface::class));
+                $plugin->setMailerFactory($container->get(MailerFactoryInterface::class));
 
                 return $plugin;
             })

plugins/system/tasknotification/src/Extension/TaskNotification.php

@@ -15,6 +15,7 @@
 use Joomla\CMS\Factory;
 use Joomla\CMS\Helper\UserGroupsHelper;
 use Joomla\CMS\Log\Log;
+use Joomla\CMS\Mail\MailerFactoryAwareTrait;
 use Joomla\CMS\Mail\MailTemplate;
 use Joomla\CMS\Plugin\CMSPlugin;
 use Joomla\CMS\User\UserFactoryAwareTrait;
@@ -46,6 +47,7 @@ final class TaskNotification extends CMSPlugin implements SubscriberInterface
 {
     use DatabaseAwareTrait;
     use UserFactoryAwareTrait;
+    use MailerFactoryAwareTrait;
 
     /**
      * The task notification form. This form is merged into the task item form by {@see
@@ -329,7 +331,7 @@ private function sendMail(string $template, array $data, string $attachment = ''
         // Mail all matching users.
         foreach ($users as $user) {
             try {
-                $mailer = new MailTemplate($template, $app->getLanguage()->getTag());
+                $mailer = new MailTemplate($template, $app->getLanguage()->getTag(), $this->getMailerFactory()->createMailer());
                 $mailer->addTemplateData($data);
                 $mailer->addRecipient($user->email);