Bug #65111 [Asn]: Calling traits directly with static properties/methods
Edit report at https://bugs.php.net/bug.php?id=65111&edit=1
ID: 65111
Updated by: gron@php.net
Reported by: ryan dot brothers at gmail dot com
Summary: Calling traits directly with static
properties/methods
Status: Assigned
Type: Bug
Package: Class/Object related
Operating System: Linux
PHP Version: 5.5.0
Assigned To: gron
Block user comment: N
Private report: N
New Comment:
Yes, traits are not supposed to be instantiated. However, this behavior is not
really related to instantiation.
Traits are still a lexical entity, i.e., a programming language entity that
provides a lexical scope when defined. Since PHP allows us to define functions in
such scopes, we can define also static methods on traits.
The way to avoid that would be to change the grammar for traits.
I decided to not do that back in the day. And I still feel that it is unclear
whether it would be conceptually cleaner if it is not possible to defined static
state/methods.
So, I would leave it as it is. Except, someone comes up with a good reason to
change it. But it would also be quite a bit of a BC issue.
Previous Comments:
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[2013-06-25 04:30:41] laruence@php.net
hmm, trait is actually a class in php, I have a quick look into this.. changing
this will needs a significant works..
actually, the is_callable / do_call alreay is a little mess now. I mean the codes
------------------------------------------------------------------------
[2013-06-24 16:52:52] ryan dot brothers at gmail dot com
Description:
------------
The documentation for traits indicates that "it is not possible to instantiate a Trait on its
own", but I have noticed that a trait can be called directly if it has a static property or
method, as per the below example. Is this intended behavior? Or should traits be restricted from
being called directly? I was under the impression that traits cannot be called directly per the
documentation. If not, is there a way to prevent traits from being called directly as in the below
example?
Test script:
---------------
<?php
trait t1
{
public static $a1 = 'test1';
public static function test()
{
return 'test2';
}
}
echo t1::$a1."\n";
echo t1::test()."\n";
Expected result:
----------------
Fatal Error that traits cannot be called directly.
Actual result:
--------------
test1
test2
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Thread (6 messages)