Bug #78480 [Opn]: The typed properties miss an important "function"
| From: | manchokapitancho at gmail dot com | Date: | Sat, 31 Aug 2019 14:05:20 +0000 |
| Subject: | Bug #78480 [Opn]: The typed properties miss an important "function" | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-222509@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=78480&edit=1
ID: 78480
User updated by: manchokapitancho at gmail dot com
Reported by: manchokapitancho at gmail dot com
Summary: The typed properties miss an important "function"
Status: Open
Type: Bug
Package: Scripting Engine problem
PHP Version: 7.4.0beta4
Block user comment: N
Private report: N
New Comment:
A simplified use case would be:
//orm with lazy loading from DB
class something {
public ?<class|self> $parent;
....
function getParent() {
if (! is_initialized($this->parent)) {
$this->parent = //fetch from DB; value could be NULL
}
return $this->parent;
}
...
}
A plain function is indeed possible but the call parameters should be ($obj, 'prop) since
($obj->prop) would throw TypeError.
Previous Comments:
------------------------------------------------------------------------
[2019-08-31 11:42:08] nikic@php.net
What's your use-case?
A language construct for this is very unlikely, but if this is a common and performance-critical
operation, a plain function could be provided in lieu of going through reflection.
------------------------------------------------------------------------
[2019-08-30 21:27:50] manchokapitancho at gmail dot com
Description:
------------
The new PHP 7.4 feature - typed properties is a great addition to the language.
As a side effect it adds a brand new state of the class/object properties - initialized=yes/no.
If one tries to access an uninitialized property, a TypeError is being thrown.
isset($object->prop) does not trigger TypeError but it returns false if $object->prop is NULL.
The suggested check is only indirectly possible via the long construct
(new ReflectionProperty(<name>::class, '<prop>'))->isInitialized($obj)
On the other side, unset works perfectly well and returns a property back into the uninitialized
state.
This write-only asymmetry is not consistent and I would expect a language construct similar to isset
[e.g. is_initialized($obj->prop)] that handles this case.
Test script:
---------------
class test {
public ?int $prop;
}
$obj = new test;
var_dump(isset($obj->prop));
var_dump(is_initialized($obj->prop));
$obj->prop = null;
var_dump(isset($obj->prop));
var_dump(is_initialized($obj->prop));
Expected result:
----------------
false
false
false
true
Actual result:
--------------
false
<missing>
false
<missing>
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=78480&edit=1