PHPMailer::validateAddress() fails on PHP 7.3 with libpcre2 < 10.32

[yolabingo]

Due to a bug in libpcre2 < 10.32-RC1 ​https://bugs.exim.org/show_bug.cgi?id=2300,
this email regex validation fails in PHP 7.3 with PCRE_VERSION < 10.32.
One consequence of this is being unable to send a password reset link from the login page - the user sees the error
"The email could not be sent. Possible reason: your host may have disabled the mail() function."

A simple test script ​https://gist.github.com/yolabingo/68b4f037661e702742c5abb324a3d992

PHP < 7.3 uses libpcre 8.x
PHP 7.3 uses libpcre2 10.x

[yolabingo]

simple script to test the

[jrf]

Sounds very similar to #33037 ?

[SirLouen]

Reproduction Report

Description

❌ This report validates whether the issue can be reproduced.

Environment

• WordPress: 6.9-alpha-60093-src
• PHP: 7.3.33
• Server: nginx/1.29.0
• Database: mysqli (Server: 8.4.5 / Client: mysqlnd 5.0.12-dev)
• Browser: Chrome 138.0.0.0
• OS: Windows 10/11
• Theme: Twenty Twenty-Five 1.2
• MU Plugins: None activated
• Plugins:
  • Test Reports 1.2.0

Testing Instructions

1. I followed the one provided by OP, using the test script, results below

Actual Results

• ❌ Error condition is not occurring any more.

Additional Notes

• This is a very old report that has not aged well, PCRE versions have been updated and all seem to be resulting as expected. I will be closing this now because it's not affecting any more, as worksforme

Supplemental Artifacts

Script results:

PHP version: 7.2.34
PCRE version: 8.41
Wordpress email validation preg_match succeeded

PHP version: 7.3.33
PCRE version: 10.32
Wordpress email validation preg_match succeeded

PHP version: 7.4.33
PCRE version: 10.35 2020-05-09
Wordpress email validation preg_match succeeded