php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #74350 defined() not working for $objectinstance::CLASS_CONSTANT
Submitted: 2017-03-31 17:50 UTC Modified: 2017-03-31 18:03 UTC
From: Andy_Schmidt at HM-Software dot com Assigned:
Status: Not a bug Package: Class/Object related
PHP Version: 7.1.3 OS: Windows
Private report: No CVE-ID: None
View Developer Edit
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: Andy_Schmidt at HM-Software dot com
New email:
PHP Version: OS:

 

 [2017-03-31 17:50 UTC] Andy_Schmidt at HM-Software dot com 
Description:
------------
defined() will function correctly for class constants, if either the class name or a classname variable is used.

However, if one tries to check the existence of a constant of the class that was used to instantiate the object, then it will return "not defined".

Test script:
---------------
class Class_A
{
	const CONST_A = 'value A';
	//    CONST_B not defined
}

$class_name = Class_A::class;

$object_A = new $class_name();

// Class references work correctly!
if ( defined( 'Class_A::CONST_A' ) )
	echo 'Class_A::CONST_A defined';

if ( defined( $class_name.'::CONST_A' ) )
	echo '$class_name::CONST_A defined';

if ( !defined( 'Class_A::CONST_B' ) )
	echo 'No Class_A::CONST_B';
		
if ( !defined( $class_name.'::CONST_B' ) )
	echo 'No $class_name::CONST_B';
			

echo $object_A::CONST_A;	// As expected, result: "value A" ! ****

// ***** Yet, using that object reference will report "not" defined! *****
if ( defined( '$object_A::CONST_A' ) )
	echo '$object_A::CONST_A defined !!';
else
	echo 'no $object_A::CONST_A';


// PS: As expected, "Fatal Error: Object of class Class_A could not be converted to string"
if ( defined( "$object_A::CONST_A" ) )
 	echo 'Should cause error, and does';

if ( defined( $object_A.'::CONST_A' ) )
 	echo 'Should cause error, and does';

Expected result:
----------------
Class_A::CONST_A defined
$class_name::CONST_A defined
No Class_A::CONST_B
No $class_name::CONST_B

value A
$object_A::CONST_A defined!!



Actual result:
--------------
Class_A::CONST_A defined
$class_name::CONST_A defined
No Class_A::CONST_B
No $class_name::CONST_B

value A
no $object_A::CONST_A

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2017-03-31 18:03 UTC] peehaa@php.net
-Status: Open +Status: Not a bug
 [2017-03-31 18:03 UTC] peehaa@php.net 
The reason you get "not" defined! is because the instance is within single quotes.

Which means it will mean a literal `$object_A` because normal string rules apply.

You can always do:

if ( defined( get_class($object_A) . '::CONST_A' ) )

to get what you want.
 [2017-03-31 18:12 UTC] Andy_Schmidt at HM-Software dot com 
Yes, I am aware how to circumvent this by obtaining the class first.

However, the point is:

 defined( 'Class_A::CONST_A' )       >>> WORKS
 defined( $class_name.'::CONST_A' )  >>> WORKS
 defined( "$class_name::CONST_A" )   >>> WORKS

But, I have found no working syntax for $object. That seems counter-intuitive, considering

 echo $object_A::CONST_A;	>>> WORKS

so "defined()" should represent that correct state.

PS - I do appreciate the dilemma presented by string substitution, object to string conversion etc. in this particular context.
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved. 		Last updated: Tue Nov 04 10:00:02 2025 UTC