Bug #70233 [NEW]: \K with preg_replace not working as expected

From: jonny5 at quantentunnel dot de Operating system: PHP version: 5.4.44 Package: PCRE related Bug Type: Bug Bug description:\K with preg_replace not working as expected Description: ------------ In certain cases, when using \K escape sequence (reset beginning of reported match) with preg_replace, result is not as expected. Every other match seems to be skipped. The test-pattern (?: |\G)\d\B\K is to separate digits of numbers preceded by start or space with *. This pattern works as expected e.g. in regex101 pcre-mode: https://regex101.com/r/gF7uB7/1 but not with preg_replace (at least with PHP 5.5.14) where it seems to skip every other zero-width match: https://eval.in/415050 Test script: --------------- <? $pattern = '~(?: |\G)\d\B\K~'; $replace = "*"; $str = "123 a123 1234567 b123"; echo preg_replace($pattern, $replace, $str); ?> Expected result: ---------------- 1*2*3 a123 1*2*3*4*5*6*7 b123 Actual result: -------------- 1*23 a123 1*23*45*67 b123 -- Edit bug report at https://bugs.php.net/bug.php?id=70233&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=70233&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=70233&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=70233&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=70233&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=70233&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=70233&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=70233&r=needscript Try newer version: https://bugs.php.net/fix.php?id=70233&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=70233&r=support Expected behavior: https://bugs.php.net/fix.php?id=70233&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=70233&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=70233&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=70233&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=70233&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=70233&r=dst IIS Stability: https://bugs.php.net/fix.php?id=70233&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=70233&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=70233&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=70233&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=70233&r=mysqlcfg