Bug #80346 [Com]: Function `array_intersect_ukey` not working (really!)
Edit report at https://bugs.php.net/bug.php?id=80346&edit=1
ID: 80346
Comment by: danack@php.net
Reported by: gilperon at gmail dot com
Summary: Function array_intersect_ukey not working
(really!)
Status: Open
Type: Bug
Package: *General Issues
Operating System: ALL
PHP Version: 7.4.12
Block user comment: N
Private report: N
New Comment:
Changing the code:
echo "DIFFERENT\n";
return 1;
to:
echo "DIFFERENT\n";
return $key2 - $key1;
Makes your code work.
It looks like this code may be sorting the arrays first, and sorting algorithms need to be stable:
https://www.geeksforgeeks.org/stability-in-sorting-algorithms/
That's an educated guess. If it is that, it's a docs problem as stability probably should
be mentioned.
Previous Comments:
------------------------------------------------------------------------
[2020-11-10 01:21:38] gilperon at gmail dot com
Description:
------------
Run the test script. It has 2 arrays in such a way that only the key 4 appears on both.
Using array_intersect_ukey does not return 4, instead it returns
array(0) {}. Using array_intersect_key works perfectly. I also realized
there is a bug in the implementation of this function, because if you run the test script it will
show you this:
|4|6|DIFFERENT
|8|6|DIFFERENT
|4|8|DIFFERENT
|3|4|DIFFERENT
|5|4|DIFFERENT
|3|5|DIFFERENT
|6|4|DIFFERENT
|6|5|DIFFERENT
|6|3|DIFFERENT
It shouldnt be comparing 8 with 6 because these keys only appear on the 1st array and these keys
shouldnt be compared at all. You can clearly see that this function, instead of comparing each key
of the first array with each key of the second array, it's comparing the keys from the first
array WITH ITSELF and then comparing the keys of the second array ITSELF (line |3|5|) and only then
comparing the keys of both arrays together (but for some reason it misses the |4|4|).
I know that in my simple use case I should be using array_intersect_key but I really
need array_intersect_ukey to work properly because I have a much more complex use case
for it.
Test script:
---------------
<?php
$array1 = array(4 => true, 6 => true, 8 => true);
$array2 = array(3 => true, 4 => true, 5 => true);
var_dump(array_intersect_ukey(
$array1,
$array2,
function ($key1, $key2) {
echo "|" . $key1 . "|" . $key2 . "|";
if ($key1 === $key2) {
echo "EQUAL\n";
return 0;
}
else{
echo "DIFFERENT\n";
return 1;
}
}
));
?>
Expected result:
----------------
It should only show the element 4, which is present in both arrays.
Actual result:
--------------
Nothing is returned from the intersection.
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=80346&edit=1
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