Use Symfony Mailer API to send mails

How we can skip actual sending of email? I mean the case when I want to pass all the phases, createParams, build, preRender etc, besides actual sending.

I got an answer.

If this is the case you need to set $email->setTransportDsn('null://null'); in postRender() function.
@see https://symfony.com/doc/current/mailer.html#disabling-delivery

/**
   * {@inheritdoc}
   */
  public function postRender(EmailInterface $email): void {
    if ($email->getSubType() == 'notifications') {
      // Prevent email sending.
      $email->setTransportDsn('null://null');
    }
  }

I am a bit confused. The project page says: "HTML email can be sent by adding Drupal Symfony Mailer". If it works with symfony mailer why do we have this issue open?

Also, under Administration > Configuration > Web services > Simplenews > Newsletter (/admin/config/services/simplenews/settings/newsletter) it says:

Install Swift Mailer → to send HTML emails or emails with attachments (both plain text and HTML).

Should it be updated to say Drupal Symfony Mailer → instead?

I just tried with Symfony Mailer installed and can confirm that Simplenews works well. HTML elements such as images and links are sent and rendered as expected.

Should it be updated to say Drupal Symfony Mailer instead?

Yes good point. In fact there are 13 matches of "swift" in various files in this module. I raised 📌 Replace references to swiftmailer with Drupal Symfony Mailer Active .

If it works with symfony mailer why do we have this issue open?

Good question.

• Currently it works with this module sending mails through the "old" mail API, then Drupal Symfony Mailer (DSM) intercepts them and converts to the new API.
• This issue would change this module to send directly through the new DSM API.

I updated the title to make this clearer.