TYPO3 Core

Is there any reason why function setHeaders() first clears $this->headers ?
It is not possible to use the public function add_header() and the "regular" way to send the mail with sendTheMail().

Couldn't the line 464 $this->headers = ''; be removed?

A workaround is to sent the mail without using the send function:

$htmlMail = t3lib_div::makeInstance('t3lib_htmlmail');
$htmlMail->start();

/* do something */

/* then send "manually" and set additional headers*/
$htmlMail->setHeaders();

$htmlMail->add_header('Envelope-From: <user@domain.tld>');

$htmlMail->setContent();
$htmlMail->sendTheMail();
(issue imported from #M10710)