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List:       php-doc-bugs
Subject:    [DOC-BUGS] Doc #64909 [Opn]: array_merge - Return value documentation incorrect/misleading
From:       "tim dot hentenaar at gmail dot com" <php-bugs () lists ! php ! net>
Date:       2013-05-24 20:30:53
Message-ID: E1UfydZ-0008W8-DN () sgrv2 ! php ! net
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Edit report at https://bugs.php.net/bug.php?id=64909&edit=1

 ID:                 64909
 User updated by:    tim dot hentenaar at gmail dot com
 Reported by:        tim dot hentenaar at gmail dot com
 Summary:            array_merge - Return value documentation
                     incorrect/misleading
 Status:             Open
 Type:               Documentation Problem
 Package:            Documentation problem
 Operating System:   N/A
 PHP Version:        5.4.15
 Block user comment: N
 Private report:     N

 New Comment:

Hi Pete,

Yes, that was my point exactly. In the example code, I didn't adhere to the 
signature of the function by passing a non-array argument. The method 
also doesn't adhere to its own signature by returning a non-array value. :P 

If one assumes, by the docs, that array_merge() will return the 'resulting 
array', then I would expect that even in case of error that array_merge() will 
still return something (empty or otherwise) of the 'array' type. It should 
probably be noted in the "Return values" section that NULL might possibly be 
returned in that particular case, since the implementation of array_merge() 
clearly does.


Previous Comments:
------------------------------------------------------------------------
[2013-05-24 17:57:08] pete at petermcdonald dot co dot uk

There is quite a large warning on the documentation advising that php5 MUST have 
arrays passed to it. It might be worth adding to the note advising of unexpected 
behaviour if array's are not passed but you have not adhered to the signature of 
the function therefore unexpected behaviour is for want of a better phrase, 
expected.

------------------------------------------------------------------------
[2013-05-23 14:04:28] tim dot hentenaar at gmail dot com

Description:
------------
---
From manual page: http://www.php.net/function.array-merge#refsect1-
function.array-merge-returnvalues
---

"Return Values: Returns the resulting array."

The documentation for the return values of array_merge() is not entirely 
correct. In fact, array_merge() will return NULL if one of its arguments is not 
an array, along with giving a warning.

Either the documentation is wrong, and returning NULL is intended here, in which 
case the documentation needs to be updated; or array_merge() should be made to 
return an array (empty, or perhaps the initial array) in this case, since the 
documentation indicates that array_merge() returns an array.

Test script:
---------------
<?php

# This shows that $r is actually assigned NULL.
$r = array_merge(array('a' => 'b'),1);
var_dump($r);

?>

Expected result:
----------------
That the variable $r should be an array, with or without the warning.

Actual result:
--------------
Warning: array_merge(): Argument #2 is not an array in 
/home/tim/php/array_merge_test.php on line 4
NULL


------------------------------------------------------------------------



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