Bug #76909 [NEW]: preg_match difference between 7.3 and < 7.3

From: jay at diablomedia dot com Operating system: Linux PHP version: 7.3.0RC1 Package: *Regular Expressions Bug Type: Bug Bug description:preg_match difference between 7.3 and < 7.3 Description: ------------ I was testing a fork of Zend Framework 1 that we maintain for our legacy applications against php 7.3.0rc1 and noticed the Zend_Validate component's tests were failing on php 7.3: https://travis-ci.org/diablomedia/zf1-validate/jobs/431170057 In this case, php 7.3 is allowing some hostnames through validation that are being rejected in php < 7.3. I dug a bit, and was able to reproduce this with a single regular expression that is evaluated differently in php 7.3 than it is in php 5.6 through php 7.2. Here's a link to 3v4l.org demonstrating the difference (script is in the "Test script" section of this report): https://3v4l.org/DR3S5 Test script: --------------- <?php $domainPart = ' domain.com'; $regexChar = '/^[\x{0100}-\x{017f}]{1,63}$/iu'; preg_match($regexChar, $domainPart, $matches); print_r($matches); Expected result: ---------------- I would expect the $matches array in the test script to be empty here, similar to all PHP versions before 7.3. Actual result: -------------- The regex matches on " domain.com", which it doesn't in earlier versions of PHP. -- Edit bug report at https://bugs.php.net/bug.php?id=76909&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=76909&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=76909&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=76909&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=76909&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=76909&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=76909&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=76909&r=needscript Try newer version: https://bugs.php.net/fix.php?id=76909&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=76909&r=support Expected behavior: https://bugs.php.net/fix.php?id=76909&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=76909&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=76909&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=76909&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=76909&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=76909&r=dst IIS Stability: https://bugs.php.net/fix.php?id=76909&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=76909&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=76909&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=76909&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=76909&r=mysqlcfg