Bug #72194 [NEW]: unset() on declared class properties triggers warnings when accessing it later

From: pierre dot rineau at makina-corpus dot com Operating system: Any PHP version: Irrelevant Package: Reflection related Bug Type: Bug Bug description:unset() on declared class properties triggers warnings when accessing it later Description: ------------ If you declare a class with declared properties, you might want to use unset() to reset the property value to null, but when accessing it later, it causes a "undefined property" warning. This seems legit, but it becomes tricky once you notice that property_exists() returns true before calling unset(), which is the wanted behavior since the property is declared (even when uninitialized), but it also returns true after calling unset(), which is incompatible with the "undefined property" warning. It seems to always have worked this way, but any code using property_exists() will be tricked by the false positive. [someuser@localhost] ~/current > php -v PHP 5.5.25 (cli) (built: May 14 2015 10:02:12) Copyright (c) 1997-2015 The PHP Group Zend Engine v2.5.0, Copyright (c) 1998-2015 Zend Technologies with Zend OPcache v7.0.4-dev, Copyright (c) 1999-2015, by Zend Technologies with Xdebug v2.4.0RC2, Copyright (c) 2002-2015, by Derick Rethans [someuser@localhost] ~/current > php -a Interactive shell php > class A { public $b; }; php > $a = new A; php > echo property_exists($a, 'b'); 1 php > $a->b; php > unset($a->b); php > echo property_exists($a, 'b'); 1 php > $a->b; PHP Notice: Undefined property: A::$b in php shell code on line 1 PHP Stack trace: PHP 1. {main}() php shell code:0 php > pounard@guinevere] ~ > php -v PHP 7.0.6 (cli) (built: May 1 2016 07:39:38) ( NTS ) Copyright (c) 1997-2016 The PHP Group Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies with Xdebug v2.4.0, Copyright (c) 2002-2016, by Derick Rethans [pounard@guinevere] ~ > php -a PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php/modules/redis.so' - /usr/lib/php/modules/redis.so: undefined symbol: zval_used_for_init in Unknown on line 0 Interactive shell php > class A { public $b; }; php > $a = new A; php > echo property_exists($a, 'b'); 1 php > $a->b; php > unset($a->b); php > echo property_exists($a, 'b'); 1 php > $a->b; PHP Notice: Undefined property: A::$b in php shell code on line 1 PHP Stack trace: PHP 1. {main}() php shell code:0 php > Test script: --------------- class A { public $b; }; $a = new A; echo property_exists($a, 'b'); // Returns '1' $a->b; // Remains silent unset($a->b); echo property_exists($a, 'b'); // Still returns '1' $a->b; // Cause a "Notice: Undefined property A::$b" -- Edit bug report at https://bugs.php.net/bug.php?id=72194&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=72194&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=72194&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=72194&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=72194&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=72194&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=72194&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=72194&r=needscript Try newer version: https://bugs.php.net/fix.php?id=72194&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=72194&r=support Expected behavior: https://bugs.php.net/fix.php?id=72194&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=72194&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=72194&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=72194&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=72194&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=72194&r=dst IIS Stability: https://bugs.php.net/fix.php?id=72194&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=72194&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=72194&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=72194&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=72194&r=mysqlcfg