XF 2.0 Error "preg_split() expects parameter 2 to be string, array given"

[affLIFT]

I've seen this pop up quite a few times in the past week. It doesn't appear to be caused by an add-on. Any ideas?

 

[Ozzy47]

Are you using any addons that touch the email system or send emails?

Can you copy & paste the full error including the request state.

 

[affLIFT]

Are you using any addons that touch the email system or send emails?

Can you copy & paste the full error including the request state.

I do have add-ons that use the email system.

ErrorException: Email to useremail@gmail.com failed: [E_WARNING] preg_split() expects parameter 2 to be string, array given
src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mime/Headers/AbstractHeader.php:337

Stack trace

#0 [internal function]: XF::handlePhpError(2, '[E_WARNING] pre...', '/var/www/html/f...', 337, Array)
#1 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mime/Headers/AbstractHeader.php(337): preg_split('~(?=[\\t ])~', Array)
#2 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mime/Headers/AbstractHeader.php(284): Swift_Mime_Headers_AbstractHeader->getEncodableWordTokens(Array)
#3 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mime/Headers/UnstructuredHeader.php(106): Swift_Mime_Headers_AbstractHeader->encodeWords(Object(Swift_Mime_Headers_UnstructuredHeader), Array)
#4 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mime/SimpleHeaderSet.php(324): Swift_Mime_Headers_UnstructuredHeader->getFieldBody()
#5 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mime/SimpleMimeEntity.php(519): Swift_Mime_SimpleHeaderSet->toString()
#6 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mime/SimpleMessage.php(617): Swift_Mime_SimpleMimeEntity->toByteStream(Object(Swift_Transport_StreamBuffer))
#7 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Message.php(170): Swift_Mime_SimpleMessage->toByteStream(Object(Swift_Transport_StreamBuffer))
#8 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(327): Swift_Message->toByteStream(Object(Swift_Transport_StreamBuffer))
#9 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(428): Swift_Transport_AbstractSmtpTransport->_streamMessage(Object(Swift_Message))
#10 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(444): Swift_Transport_AbstractSmtpTransport->_doMailTransaction(Object(Swift_Message), 'hello@afflift.c...', Array, Array)
#11 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(176): Swift_Transport_AbstractSmtpTransport->_sendTo(Object(Swift_Message), 'hello@afflift.c...', Array, Array)
#12 src/XF/Mail/Mailer.php(289): Swift_Transport_AbstractSmtpTransport->send(Object(Swift_Message), Array)
#13 src/XF/Mail/Queue.php(65): XF\Mail\Mailer->send(Object(Swift_Message))
#14 src/XF/Job/MailQueue.php(11): XF\Mail\Queue->run(8)
#15 src/XF/Job/Manager.php(241): XF\Job\MailQueue->run(8)
#16 src/XF/Job/Manager.php(187): XF\Job\Manager->runJobInternal(Array, 8)
#17 src/XF/Job/Manager.php(76): XF\Job\Manager->runJobEntry(Array, 8)
#18 job.php(15): XF\Job\Manager->runQueue(false, 8)
#19 {main}

array(4) {
["url"] => string(10) "/f/job.php"
["referrer"] => string(22) "https://afflift.com/f/"
["_GET"] => array(0) {
}
["_POST"] => array(0) {
}
}

 

[Mike]

This isn't something we've had any other reports of, so it very well could be related to an add-on. The trace doesn't show it, but this is handling the mail queue; the mail building process would be the potential place for incorrect data to be set. Unfortunately, that's fairly difficult to debug, short of disabling add-ons to see if it keeps happening.

Beyond that, the only thing I could recommend is checking your email-related settings in the XF options. Make sure you've set values that are correct/valid for each of them. (Random thing that comes to mind is whether there are multiple emails set somewhere where one is expected, though that would likely block every mail.)

 

[affLIFT]

Okay, appreciate your help, @Mike