Bug #15273 Updated: Reference to array breaks

ID: 15273 Updated by: eru@php.net Reported By: mvl@nikhef.nl -Status: Open +Status: Bogus Bug Type: Arrays related Operating System: Linux PHP Version: 4.1.1 New Comment: It took me a while to realize it myself, but RTFMing helps: http://www.php.net/manual/en/language.references.unset.php explains it quite well. Through unset'ting the $b_nw; you turn the reference in $bb into a copy, that's why the array is not changing its values. On the other side, the [1]-entry in $aa remains a true reference, so when you change $a_nw in the second pass, you change the [1]-entry as well, as it is still a reference to $a_nw. If you use var_dump in exchange for print_r, you can see the references in the arrays much better, as they're prefixed with an ampersand. Expected behaviour -> bogus. Previous Comments: ------------------------------------------------------------------------ [2002-01-29 05:21:15] mvl@nikhef.nl Hi, Below you will find a piece of code which is intended to make two two-dimensional arrays: $aa and $bb. In fact, both arrays should be the same, as far as I can see. It seems however that the unset($b_nw) is crucial. As far as I understood from the documentation, an assignement with an arrray on the right-hand side should perfrom a copy of the array. My assumption is that the same should be true with a reference to an array, because there is no way to distinguish between them. So please have a look at my code and tell me when you need more information, or if I misunderstood something. The code: <?php $a=array(0); $b=array(0); $aa=array(&$a); $bb=array(&$b); for ($i=1; $i<3; $i++) { $a_nw=$a; $a_nw[]=$i; $aa[]=&$a_nw; $b_nw=$b; $b_nw[]=$i; $bb[]=&$b_nw; unset($b_nw); } echo "<b>aa: </b>"; print_r($aa); echo "<br>\n"; echo "<b>bb: </b>"; print_r($bb); echo "<br>\n"; ?> The output: aa: Array ( [0] => Array ( [0] => 0 ) [1] => Array ( [0] => 0 [1] => 2 ) [2] => Array ( [0] => 0 [1] => 2 ) ) bb: Array ( [0] => Array ( [0] => 0 ) [1] => Array ( [0] => 0 [1] => 1 ) [2] => Array ( [0] => 0 [1] => 2 ) ) Note that $aa[1] != $bb[1], which is unexepected ($bb[1] is the correct value, I think). Thanks, Marco. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=15273&edit=1