Description
Description
The filter_var function has the following description:
filter_var(mixed $value, int $filter = FILTER_DEFAULT, array|int $options = 0): mixed
The "callback signature" [description] of the User Defined Filter of the FILTER_CALLBACK filter is:
callback(string $value): mixed
Problem:
This inconsistency prevents FILTER_CALLBACK from being used to sanitize arrays, such as those set in the predefined variables after an HTTP POST request.
e.g.: The following code generates a type error. [EDIT 2025-06-09:] The code sample in this post does not demonstrate the reported problem, see updated sample here: #4726
<?php
unset($json);
$json=filter_var(
value:$_POST['array'],
filter:FILTER_CALLBACK,
options:[
'options'=>function(
mixed $value,
):mixed{
return json_encode($value);
},
],
);Solution:
The type of the $value parameter in the "callback signature" [description] should be changed to match its filter_var calling function. i.e.:
callback(mixed $value): mixed
PHP Version
PHP 8.4.7 (cli) (built: May 9 2025 07:02:39) (NTS)
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