Bug #71238 [Com]: usort pass by reference inconsistency
| From: | white06tiger+PHPbug at gmail dot com | Date: | Sun, 03 Jan 2016 14:46:18 +0000 |
| Subject: | Bug #71238 [Com]: usort pass by reference inconsistency | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-198383@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=71238&edit=1
ID: 71238
Comment by: white06tiger+PHPbug at gmail dot com
Reported by: eugen dot alter at gmail dot com
Summary: usort pass by reference inconsistency
Status: Open
Type: Bug
Package: Arrays related
Operating System: any
PHP Version: 7.0.1
Block user comment: N
Private report: N
New Comment:
I have the same issue with
uksort() and WITHOUT modifying the actual array.
This bug seems to trigger as soon as anything accesses the array to be sorted.
Following code is supposed to sort an array by values and key (in this case, behaves like a stable
sort)
```
<?php
error_reporting(-1);
header('Content-Type: text/plain');
function uasort_key(&$arr, $func) {
return uksort($arr, function($a,$b) use(&$arr,$func) {
return $func($arr[$a], $arr[$b], $a, $b);
});
}
function sort_me($a, $b, $ka = 0, $kb = 0) {
return ($a < $b ? -1 : ($a > $b ? 1 :
($ka < $kb ? -1 : ($ka > $kb ? 1 : 0))
));
}
$test_array = array(4,6,2,1,7,5,1,34,1,0,4);
$test_array_uasort = $test_array;
$test_array_uasort_key = $test_array;
uasort($test_array_uasort, 'sort_me');
uasort_key($test_array_uasort_key, 'sort_me');
echo 'PHP: ', phpversion(), "\n\n";
echo 'Unsorted: ';
print_r($test_array);
echo 'uasort: ';
print_r($test_array_uasort);
echo 'uasort_key: ';
print_r($test_array_uasort_key);
echo "\n\n", 'Source: ', "\n\n";
readfile(__FILE__);
?>
```
In PHP 5.3 you'll get the false-positive warning:
âWarning: uksort(): Array was modified by the user comparison function in sort_bug.php on line
8â which got seemingly fixed in bug #50688 for PHP 7.. Maybe said "fix" introduced
our current faulty behavior.
Expected result (PHP 5.3):
-----
uasort_key: Array
(
[9] => 0
[3] => 1
[6] => 1
[8] => 1
[2] => 2
[0] => 4
[10] => 4
[5] => 5
[1] => 6
[4] => 7
[7] => 34
)
-----
Actual result (PHP 7.0.1):
-----
uasort_key: Array
(
[9] => 0
[6] => 1
[3] => 1
[2] => 2
[0] => 4
[1] => 6
[10] => 4
[8] => 1
[5] => 5
[4] => 7
[7] => 34
)
-----
Previous Comments:
------------------------------------------------------------------------
[2015-12-29 18:24:50] levim@php.net
Using var_export in PHP 5.5:
array (
0 =>
array (
'name' => 'Bar',
'children' =>
array (
0 =>
array (
'name' => 'X',
'children' =>
array (
),
),
1 =>
array (
'name' => 'Y',
'children' =>
array (
),
),
2 =>
array (
'name' => 'Z',
'children' =>
array (
),
),
),
),
1 =>
array (
'name' => 'Foo',
'children' =>
array (
0 =>
array (
'name' => 'A',
'children' =>
array (
),
),
1 =>
array (
'name' => 'B',
'children' =>
array (
),
),
),
),
)
Using var_export in a slightly outdated master branch:
array (
0 =>
array (
'name' => 'Bar',
'children' =>
array (
0 =>
array (
'name' => 'Z',
'children' =>
array (
),
),
1 =>
array (
'name' => 'X',
'children' =>
array (
),
),
2 =>
array (
'name' => 'Y',
'children' =>
array (
),
),
),
),
1 =>
array (
'name' => 'Foo',
'children' =>
array (
0 =>
array (
'name' => 'B',
'children' =>
array (
),
),
1 =>
array (
'name' => 'A',
'children' =>
array (
),
),
),
),
)
------------------------------------------------------------------------
[2015-12-29 16:38:59] eugen dot alter at gmail dot com
Description:
------------
In PHP 5.4 ... 5.6 passing compared array elements by reference and then changing them from inside
comparison function works properly whilst in PHP7 it does not.
In sample script: function tries to sort arrays by key "name" on all nested levels. The
nested levels are sorted correctly on PHP 5.4 .. 5.6 but not on PHP7.
Test script:
---------------
$array = [
[
'name' => 'Foo',
'children' => [
[
'name' => 'B',
'children' => []
],
[
'name' => 'A',
'children' => []
]
]
],
[
'name' => 'Bar',
'children' => [
[
'name' => 'Z',
'children' => []
],
[
'name' => 'X',
'children' => []
],
[
'name' => 'Y',
'children' => []
]
]
]
];
usort($array, $f = function(&$x, &$y) use (&$f){
usort($x['children'], $f);
usort($y['children'], $f);
return strcasecmp($x['name'], $y['name']);
});
Expected result:
----------------
array(2) { [0]=> array(2) { ["name"]=> string(3) "Bar"
["children"]=> array(3) { [0]=> array(2) { ["name"]=> string(1)
"X" ["children"]=> array(0) { } } [1]=> array(2) { ["name"]=>
string(1) "Y" ["children"]=> array(0) { } } [2]=> array(2) {
["name"]=> string(1) "Z" ["children"]=> array(0) { } } } }
[1]=> array(2) { ["name"]=> string(3) "Foo" ["children"]=>
array(2) { [0]=> array(2) { ["name"]=> string(1) "A"
["children"]=> array(0) { } } [1]=> array(2) { ["name"]=> string(1)
"B" ["children"]=> array(0) { } } } } }
Actual result:
--------------
array(2) { [0]=> array(2) { ["name"]=> string(3) "Bar"
["children"]=> array(3) { [0]=> array(2) { ["name"]=> string(1)
"Z" ["children"]=> array(0) { } } [1]=> array(2) { ["name"]=>
string(1) "X" ["children"]=> array(0) { } } [2]=> array(2) {
["name"]=> string(1) "Y" ["children"]=> array(0) { } } } }
[1]=> array(2) { ["name"]=> string(3) "Foo" ["children"]=>
array(2) { [0]=> array(2) { ["name"]=> string(1) "B"
["children"]=> array(0) { } } [1]=> array(2) { ["name"]=> string(1)
"A" ["children"]=> array(0) { } } } } }
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=71238&edit=1