note 127138 added to function.array-combine

There is an inconsistent behavior in the function implementation that I'd like to warn about as it may be very hard to debug on larger arrays, regarding members data type of the input array used for keys. I have noticed this behavior in PHP version 5.5 and haven't tested it in any other version. Suppose the input array used for keys consists of members of string type, but some of those string members by chance consist only of digit characters, so that they can be implicitly type-casted to a valid integer. The implementation of array_combine() will do just that - in the resulting array the string member from the keys array will be silently converted into integer type, turning that resulting array member into regular indexed member instead of expected "key" => "value" pair. Worse still, if the keys input array consists of mixed type members, containing both integer and string type data, then there is a chance that inadvertently converted string member may duplicate some other member being intentionally of integer type. Here is my example on which I discovered this behavior. The array used for keys is like this: array (size=4) 0 => string '00000000' (length=8) 1 => string '22222222' (length=8) 2 => string 'AAAAAAAA' (length=8) 3 => string 'QQQQQQQQ' (length=8) I needed to combine this array with an array of flags, like this: array (size=4) 0 => string '0' (length=1) 1 => string '0' (length=1) 2 => string '1' (length=1) 3 => string '0' (length=1) The result of array_combine($keys, $flags): array (size=4) '00000000' => string '0' (length=1) 22222222 => string '0' (length=1) 'AAAAAAAA' => string '1' (length=1) 'QQQQQQQQ' => string '0' (length=1) Notice that a second member of a resulting array has lost the string data type and is converted into integer type, making it an indexed member with an index 22222222 instead of intended '22222222' => '0' pair. ---- Server IP: 45.112.84.4 Probable Submitter: 80.90.12.131 (proxied: 195.222.97.162) ---- Manual Page -- https://php.net/manual/en/function.array-combine.php Edit -- https://main.php.net/note/edit/127138 Del: integrated -- https://main.php.net/note/delete/127138/integrated Del: useless -- https://main.php.net/note/delete/127138/useless Del: bad code -- https://main.php.net/note/delete/127138/bad+code Del: spam -- https://main.php.net/note/delete/127138/spam Del: non-english -- https://main.php.net/note/delete/127138/non-english Del: in docs -- https://main.php.net/note/delete/127138/in+docs Del: other reasons-- https://main.php.net/note/delete/127138 Reject -- https://main.php.net/note/reject/127138 Search -- https://main.php.net/manage/user-notes.php