#39713 [NEW]: Static variables defined in static methods duplicated in derived classes

From: paul at digitalbacon dot us Operating system: Linux, Mac OS X 10.4, Windows XP PHP version: 5.2.0 PHP Bug Type: Scripting Engine problem Bug description: Static variables defined in static methods duplicated in derived classes Description: ------------ When using a static variable defined inside a parent class's static method block, different outcomes can occur depending on the scope name used when calling. The effect is that a non-overridden method in the child class is allocated a completely separate static variable... not how it works in C or C++, which I know PHP is not. I encountered this problem implementing a singleton pattern in a parent class. I apologize for the reproduction code, but it does illustrate my perceived problem. The closest bugs I found, relate to static class attributes, not regular static variables. Reproduce code: --------------- <?php class TheParent { public static function staticMethod() { static $theStaticValue = true; if ($theStaticValue == true) { $theStaticValue = false; return true; } else return $theStaticValue; // false } } class TheChild extends TheParent {} $a1 = TheParent::staticMethod(); $a2 = TheParent::staticMethod(); $b1 = TheChild::staticMethod(); $b2 = TheChild::staticMethod(); echo '$a1: ', $a1, "\n"; // true echo '$a2: ', $a2, "\n"; // false echo '$b1: ', $b1, "\n"; // true (I believe this should be false) echo '$b2: ', $b2, "\n"; // false ?> Expected result: ---------------- My intuition tells me that the parent's static variable should be used regardless of the scope name used... unless it's actually redefined in the child class. In this example, I expect the output to be: $a1: 1 $a2: $b1: $b2: Is local static method data not shared? Actual result: -------------- $a1: 1 $a2: $b1: 1 $b2: -- Edit bug report at http://bugs.php.net/?id=39713&edit=1 -- Try a CVS snapshot (PHP 4.4): http://bugs.php.net/fix.php?id=39713&r=trysnapshot44 Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=39713&r=trysnapshot52 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=39713&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=39713&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=39713&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=39713&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=39713&r=needscript Try newer version: http://bugs.php.net/fix.php?id=39713&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=39713&r=support Expected behavior: http://bugs.php.net/fix.php?id=39713&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=39713&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=39713&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=39713&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=39713&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=39713&r=dst IIS Stability: http://bugs.php.net/fix.php?id=39713&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=39713&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=39713&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=39713&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=39713&r=mysqlcfg