Bug #76376 [NEW]: preg_match fails to match pattern with backslash in the beginning of string.

From: alexander dot aka dot alegz at gmail dot com Operating system: Centos 7 PHP version: 7.0.30 Package: Regexps related Bug Type: Bug Bug description:preg_match fails to match pattern with backslash in the beginning of string. Description: ------------ OS: CentOS7 Source repo: remi Version: PHP 7.0.30 (built: Apr 24 2018 21:28:23) ( NTS ) Reproduced both in cli and with web-server (as apache module). Environment is pre-configured with bitrix-env (https://training.bitrix24.com/support/training/course/index.php?COURSE_ID=113&LESSON_ID=9463&LESSON_PATH=9681.9461.9463) on LXC container. Test script: --------------- <?php $a = 'abc'; var_dump(preg_match('/^a/', $a)); $a = 'a\bc'; var_dump(preg_match('/^a\\b/', $a)); $a = '\abc'; var_dump(preg_match('/^\\a/', $a)); Expected result: ---------------- int(1) int(1) int(1) Actual result: -------------- int(1) int(1) int(0) -- Edit bug report at https://bugs.php.net/bug.php?id=76376&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=76376&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=76376&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=76376&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=76376&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=76376&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=76376&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=76376&r=needscript Try newer version: https://bugs.php.net/fix.php?id=76376&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=76376&r=support Expected behavior: https://bugs.php.net/fix.php?id=76376&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=76376&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=76376&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=76376&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=76376&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=76376&r=dst IIS Stability: https://bugs.php.net/fix.php?id=76376&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=76376&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=76376&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=76376&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=76376&r=mysqlcfg