PHP 4.0 Bug #10668 Updated: preg_replace backquote failure

ID: 10668 User Update by: smoonen@andstuff.org Status: Analyzed Bug Type: PCRE related Description: preg_replace backquote failure H'm... I'm confused. :-) To complicate things further, the e-mails display half as many backslashes as the web page. :-) Since I'm not sure what you mean, I'll exhaustively list the behaviors: The following: $str = "abc'\\\\''def"; function f($s) { var_dump($s); return "x"; } print preg_replace("/c(.*)d/e", "f('\\1')", $str); gives the error messages I posted earlier. (That's two backslashes before the 1.) The following: $str = "abc'\\\\''def"; function f($s) { var_dump($s); return "x"; } print preg_replace("/c(.*)d/e", "f('\\\\1')", $str); gives the result: string(2) "\1" abxef which isn't what I want. (That's four backslashes before the 1.) Prefixing the "1" with one or three backslashes in each case emits an ASCII x'01'. None of which are what I want to occur... Previous Comments: --------------------------------------------------------------------------- [2001-05-04 15:17:51] andrei@php.net Oops, \1 instead of 1. --------------------------------------------------------------------------- [2001-05-04 15:17:15] andrei@php.net Ok, I made a little mistake, use "f('\\1')" rather than "f('1')". --------------------------------------------------------------------------- [2001-05-04 13:59:27] smoonen@andstuff.org Oddly, I get the following error: Warning: Unexpected character in input: '' (ASCII=92) state=1 in /home/groups/t/ta/tavi/htdocs/playground/test.php(4) : regexp code on line 1 Parse error: parse error in /home/groups/t/ta/tavi/htdocs/playground/test.php(4) : regexp code on line 1 Fatal error: Failed evaluating code: f(''\\''') in /home/groups/t/ta/tavi/htdocs/playground/test.php on line 4 PHP compile options may be seen at: http://tavi.sourceforge.net/playground/phpinfo.php --------------------------------------------------------------------------- [2001-05-04 12:58:12] andrei@php.net Can you explain why you think it fails? The following sample (slightly modified from yours to dump the $s parameter to function): $str = "abc'\\''def"; function f($s) { var_dump($s); return "x"; } print preg_replace("/c(.*)d/e", "f('\1')", $str); outputs: string(5) "'\''" abxef As it should. --------------------------------------------------------------------------- [2001-05-04 11:44:19] smoonen@andstuff.org The following code succeeds on PHP 4.03 and PHP 4.04pl1, but fails on PHP 4.05: $str = "abc'\\''def"; function f($s) { return "x"; } print preg_replace("/c(.*)d/e", "f('\1')", $str, -1); This seems to expose *two* underlying bugs: 1) There appears to be some problem in the regex state machine 2) There is a definite problem with the replacement of the backreference with its corresponding string. --------------------------------------------------------------------------- The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online. Full Bug description available at: http://bugs.php.net/?id=10668