Mail: Set a better error code when triggering `wp_mail_failed`.

This error code is now... wait for it... `wp_mail_failed`. Previously, this would have been the originating PHPMailer error code, which could be `0`, which would then fail (pass?) the `empty()` check in the `WP_Error` constructor, thereby rendering the error object fairly useless. The PHPMailer error code is now located within the `WP_Error` data.

props Kau-Boy, stephenharris.
fixes #35598.

Built from https://develop.svn.wordpress.org/trunk@39086


git-svn-id: http://core.svn.wordpress.org/trunk@39028 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/pluggable.php

@@ -472,16 +472,17 @@ function wp_mail( $to, $subject, $message, $headers = '', $attachments = array()
 	} catch ( phpmailerException $e ) {
 
 		$mail_error_data = compact( 'to', 'subject', 'message', 'headers', 'attachments' );
+		$mail_error_data['phpmailer_exception_code'] = $e->getCode();
 
 		/**
 		 * Fires after a phpmailerException is caught.
 		 *
 		 * @since 4.4.0
 		 *
-		 * @param WP_Error $error A WP_Error object with the phpmailerException code, message, and an array
+		 * @param WP_Error $error A WP_Error object with the phpmailerException message, and an array
 		 *                        containing the mail recipient, subject, message, headers, and attachments.
 		 */
- 		do_action( 'wp_mail_failed', new WP_Error( $e->getCode(), $e->getMessage(), $mail_error_data ) );
+		do_action( 'wp_mail_failed', new WP_Error( 'wp_mail_failed', $e->getMessage(), $mail_error_data ) );
 
 		return false;
 	}

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-beta1-39085';
+$wp_version = '4.7-beta1-39086';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.