Bug #60198 [Opn->Bgs]: Array to string notice from array functions

Edit report at https://bugs.php.net/bug.php?id=60198&edit=1 ID: 60198 Updated by: rasmus@php.net Reported by: simon at simon dot geek dot nz Summary: Array to string notice from array functions -Status: Open +Status: Bogus Type: Bug Package: *General Issues PHP Version: 5.4SVN-2011-11-02 (SVN) Block user comment: N Private report: N New Comment: The problem here is that these functions aren't recursive. They just go one level deep and assume arrays of scalars. This means that the notice is a good idea because the result when you pass it nested arrays is likely not the one you wanted. For example. If we change your code example slightly: $left = [ 1, 2, [3] ]; $right = [2, 'Array']; What should the intersection of these two be? Surely just the '2' since there is no nested array with a 3 in $right and there is no string 'Array' in $left. But the actual output is: [ 2, [3] ] Oops! That's not what we expected and that is why this result gives you a notice telling you that the result is likely flawed because of an array to string conversion. Now, it might be nice if array_intersect was smarter and could handle nested arrays, but that would be a different feature enhancement bug. It also looks like this is well-documented. The array_intersect() doc page has this highlighted note: Note: Two elements are considered equal if and only if (string) $elem1 === (string) $elem2. In words: when the string representation is the same. Previous Comments: ------------------------------------------------------------------------ [2011-11-11 00:05:29] chx1975 at gmail dot com This affects the Drupal project. All our tests are failing because of this bug. We see it with array_intersect_assoc(). ------------------------------------------------------------------------ [2011-11-02 08:33:27] simon at simon dot geek dot nz Description: ------------ Some of the array_* functions that compare elements in multiple arrays do so by (string)$elem1 === (string)$elem2. If $elem1 or $elem2 is an array, then the array to string notice is thrown. Two examples of functions that can throw this are array_intersect() and array_diff(). If these functions are not expected to take arrays with other arrays as values, this should be mentioned on the documentation pages. Test script: --------------- <?php $left = array('b', array('a')); $right = array('a', 'd'); print_r(array_intersect($left, $right)); print_r(array_diff($left, $right)); Expected result: ---------------- Array ( ) Array ( [0] => b [1] => Array ( [0] => a ) ) Actual result: -------------- PHP Notice: Array to string conversion in /Users/simon/test.php on line 4 PHP Notice: Array to string conversion in /Users/simon/test.php on line 4 PHP Notice: Array to string conversion in /Users/simon/test.php on line 5 PHP Notice: Array to string conversion in /Users/simon/test.php on line 5 PHP Notice: Array to string conversion in /Users/simon/test.php on line 5 Notice: Array to string conversion in /Users/simon/test.php on line 4 Notice: Array to string conversion in /Users/simon/test.php on line 4 Array ( ) Notice: Array to string conversion in /Users/simon/test.php on line 5 Notice: Array to string conversion in /Users/simon/test.php on line 5 Notice: Array to string conversion in /Users/simon/test.php on line 5 Array ( [0] => b [1] => Array ( [0] => a ) ) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=60198&edit=1