[wp-trac] [WordPress Trac] #46217: wp_mail() not sending messages on PHP7.3.x

[WordPress Trac]

#46217: wp_mail() not sending messages on PHP7.3.x
--------------------------+-----------------------------
 Reporter:  whatevs       |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Mail          |    Version:  5.0.3
 Severity:  normal        |   Keywords:  needs-testing
  Focuses:                |
--------------------------+-----------------------------
 Hi,

 I believe that this is a bug but my PHP-fu is not yet the belt color
 needed to further debug and fix this.
 I have tested this behavior on WordPress 5.0.3 and GitHub sources from
 2019-02-07, on FreeBSD and Linux Ubuntu 18.04, with PHP 7.3.1.
 PHP versions 7.2 and older work as expected.

 While PHP's mail() sends e-mails flawlessly, there are no attempts to open
 connection to a SMTP server when using wp_mail().

 This issue covers all WordPress e-mails including the initial "New
 WordPress Site" message. Example code, working on PHP 7.2 but not on 7.3.
 {{{#!php
 <?php
 require('./wp-config.php');
 $headers = 'From: whatevs <tester at proper-and-existing-domain.net>' .
 "\r\n";
 wp_mail('something at proper-and-existing-domain.com','wp mail test','test
 test test', $headers );
 }}}
 The above example works with PHP 7.3 when "wp_mail" is replaced with
 "mail". 3rd party PHPmailer also works on PHP 7.3 with no issues.

 Upon testing this behavior with tcpdump I can see that with PHP 7.2,
 WordPress opens a connection to 127.0.0.1:25 and tries to send the
 message. With PHP 7.3 there are no attempts to establish such connection
 on lo interface nor any other.

 The following change results in: "Invalid address:  (setFrom) tester
 @proper-and-existing-domain.net"
 {{{
 --- wp-includes/pluggable.php   2019-02-08 15:37:38.459579000 +0100
 +++ wp-includes/pluggable.php-debug     2019-02-08 15:37:29.683718000
 +0100
 @@ -364,7 +364,8 @@
                         $mail_error_data['phpmailer_exception_code'] =
 $e->getCode();

                         /** This filter is documented in wp-
 includes/pluggable.php */
 -                       do_action( 'wp_mail_failed', new WP_Error(
 'wp_mail_failed', $e->getMessage(), $mail_error_data ) );
 +                       //do_action( 'wp_mail_failed', new WP_Error(
 'wp_mail_failed', $e->getMessage(), $mail_error_data ) );
 +                       print('DEBUG '.$e->getMessage().' DEBUG');
                         return false;
                 }
 }}}

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Ticket URL: <https://core.trac.wordpress.org/ticket/46217>
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