Bug #79373 [Nab]: uninitialized typed property cannot accessed in __get magic method

Edit report at https://bugs.php.net/bug.php?id=79373&edit=1 ID: 79373 Updated by: requinix@php.net Reported by: consatan at gmail dot com Summary: uninitialized typed property cannot accessed in __get magic method Status: Not a bug Type: Bug Package: Class/Object related Operating System: Linux PHP Version: 7.4.3 Block user comment: N Private report: N New Comment: > Note: while this may or may not be interpreted as a bug, it is still a major BC break. In > practice, a > PHP 7.4.0 -> 7.4.1 upgrade requires changes in how type properties (public or private) are > being > shadowed for lazy-loading purposes. And in an ideal world the behavior seen in 7.4.0 would not have made it to the release. But it did. And it was incorrect: initialized and accessible are two different and separate concepts. And __get/etc. are about accessibility. Better to fix the bug immediately and break the early adopters than to let it live until 7.5/8.0 where it would create even larger problems. Previous Comments: ------------------------------------------------------------------------ [2020-04-13 14:47:00] ocramius@php.net Note: while this may or may not be interpreted as a bug, it is still a major BC break. In practice, a PHP 7.4.0 -> 7.4.1 upgrade requires changes in how type properties (public or private) are being shadowed for lazy-loading purposes. ------------------------------------------------------------------------ [2020-03-12 17:12:04] beberlei@php.net Your example seems to be wrong, you are not accessing Foo::$bar through __get, because its public. I assume its an error while making the example small and contained. However the behavior here is correct regardless of __get or public access. You cannot access an uninitialized typed variable anywhere, before initializing it and this error represents that. ------------------------------------------------------------------------ [2020-03-12 16:56:29] consatan at gmail dot com Description: ------------ A uninitialized typed property cannot accessed in __get method until unset() it. Test on 7.4.0~7.4.3, 7.4.0 is works. Test script: --------------- <?php class Foo { public int $bar; public function __get($name) { if ('bar' === $name) { return $this->bar = 1; } } } $foo1 = new Foo(); var_dump($foo1); var_dump($foo1->bar); $foo2 = new Foo(); var_dump($foo2); unset($foo2->bar); var_dump($foo2); var_dump($foo2->bar); Expected result: ---------------- object(Foo)#1 (0) { ["bar"]=> uninitialized(int) } int(1) object(Foo)#2 (0) { ["bar"]=> uninitialized(int) } object(Foo)#2 (0) { ["bar"]=> uninitialized(int) } int(1) Actual result: -------------- object(Foo)#1 (0) { ["bar"]=> uninitialized(int) } Warning: Uncaught Error: Typed property Foo::$bar must not be accessed before initialization in php shell code:1 Stack trace: #0 {main} thrown in php shell code on line 1 object(Foo)#2 (0) { ["bar"]=> uninitialized(int) } object(Foo)#2 (0) { ["bar"]=> uninitialized(int) } int(1) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=79373&edit=1