Bug #75831 [Com]: Coalesce operator ?? never uses the default isset() handler
Edit report at https://bugs.php.net/bug.php?id=75831&edit=1
ID: 75831
Comment by: jakechapa at gmail dot com
Reported by: nobots dot nospam at example dot org
Summary: Coalesce operator ?? never uses the default isset()
handler
Status: Assigned
Type: Bug
Package: *General Issues
PHP Version: 7.2.1
Assigned To: nikic
Block user comment: N
Private report: N
New Comment:
I found the following behavior odd. Is it expected as ewll?
```
class MagicProp
{
public function __isset($key)
{
return false;
}
public function __get($prop) {
return 'yes';
}
}
$magic = new MagicProp();
return $magic->prop; // returns 'yes'
return $magic->prop ?? 1; // returns 1
```
Previous Comments:
------------------------------------------------------------------------
[2020-04-23 09:21:14] michael dot vorisek at email dot cz
Is this expected to be fixed soon - and backported or at least in PHP 8.0?
------------------------------------------------------------------------
[2019-01-25 16:24:46] nikic@php.net
I agree with the original reporter that this is a bug. $foo->bar ?? $baz should behave the same
way as isset($foo->bar) ? $foo->bar : $baz, and in this case it does not.
https://3v4l.org/UI13h
------------------------------------------------------------------------
[2018-01-21 17:23:41] timok at ya dot ru
Imho, this is not a bug, but quite expected and correct behavior.
You define a handler to get inaccessible properties (__get), then it is called whenever you try to
access an inaccessible property, including NULL coalesce operator. If object has a property check
method (__isset), then it is called before __get. So, the code
var_dump($bar->foo ?? "qux"); // works now, without errors...
- is equivalent to the following:
var_dump(isset($bar->foo) ? $bar->foo : "qux"); // also works without errors: https://3v4l.org/4EPXm
- http://php.net/manual/en/language.operators.comparison.php#language.operators.comparison.coalesce
- https://wiki.php.net/rfc/isset_ternary
------------------------------------------------------------------------
[2018-01-17 11:44:22] nobots dot nospam at example dot org
Description:
------------
The coalesce operator calls __get(prop) directly without testing isset($obj->prop) first.
It only calls isset($obj->prop) if there is an explicit user-defined __isset() handler.
Test script:
---------------
class Bar{
function __get($a){
throw new Error("no prop error\n");
}
}
$bar = new Bar;
try{
var_dump($bar->foo ?? "qux"); // error...
} catch(Throwable $e){ echo $e->getMessage(); }
var_dump(isset($bar->foo)); // ...but this works fine
Expected result:
----------------
class Bar{
function __isset($a){
return isset($this->{$a});
// I shouldn't be forced to implement this,
// since it looks exactly like the default isset() handler
}
function __get($a){
throw new Error("no prop error\n");
}
}
$bar = new Bar;
var_dump($bar->foo ?? "qux"); // works now, without errors...
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=75831&edit=1
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