From: msm at manley dot org Operating system: Linux, FreeBSD PHP version: 5.0.0 PHP Bug Type: Unknown/Other Function Bug description: extract(array, EXTR_REFS) fails if array has more than one referring symbol
Description: ------------ Is there an issue with extract() using EXTR_REFS when more than one symbol points to an array variable? EXTR_REF "extracts variables as references. This effectively means that the values of the imported variables are still referencing the values of the var_array parameter." (from http://us2.php.net/manual/en/function.extract.php) >From some experiments, I think that this function has issues when you pass it an array that has been given a reference or pass in a reference to an array itself. It three of the four testcases shown below, it would appear that the extracted variable $foo is NOT actually a reference into $array['foo'] after the extract() call. PHP does lazy copies on arrays. Does modifying an array via a reference to one of the array's members not trigger the lazy copy? This is not the bug (and makes sense to me), though it certainly added to the confusion trying to figure out what was happenning here. The testcases return the same results under PHP 4.3.4, PHP 4.3.8 and PHP 5.0.0 on all the FreeBSD, Linux and Windows systems I have access to. Reproduce code: --------------- I describe four testcases and their output at http://www.sitepoint.com/forums/showthread.php?p=1329965 Sorry, the testcases are longer than 20 lines, all total. In summary: 1) Copy array by reference -- $array_b =& $array_a -- and then extract(array, EXTR_REFS) from each. 2) Copy array by value -- $array_b = $array_a -- and then extract(array, EXTR_REFS) from each. 3) Copy array by reference, then modify a value in the array, then extract(array, EXTR_REFS) from each. 4) Copy array by value, then modify a value in the array (triggering the lazy copy), then extract(array, EXTR_REFS) from each. Expected result: ---------------- In each testcase, given an array ('foo' => 'value') I expect to see a variable $foo that is a reference to $array['foo'] and when I change $foo's value, the value of $array['foo'] should change accordingly. Actual result: -------------- Is the first three testcases $foo appears not to be a reference to $array_a['foo'] or $array_b['foo']. In the fourth testcase, extract(array, EXTR_REFS) performs as expected. -- Edit bug report at http://bugs.php.net/?id=29493&edit=1 -- Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=29493&r=trysnapshot4 Try a CVS snapshot (php5): http://bugs.php.net/fix.php?id=29493&r=trysnapshot5 Fixed in CVS: http://bugs.php.net/fix.php?id=29493&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=29493&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=29493&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=29493&r=needscript Try newer version: http://bugs.php.net/fix.php?id=29493&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=29493&r=support Expected behavior: http://bugs.php.net/fix.php?id=29493&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=29493&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=29493&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=29493&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=29493&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=29493&r=dst IIS Stability: http://bugs.php.net/fix.php?id=29493&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=29493&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=29493&r=float
