Symfony version(s) affected

6.0

Description

This bug was already mentioned in #41766 (comment)

The issue is still not fixed and get a 'Message: Input value "fieldname" contains a non-scalar value.' error now.

The set function is accepting an error and even \Stringable but the accept doesn't have the same check and is inconsistent now.
get function - vendor/symfony/http-foundation/InputBag.php:36

        if (null !== $value && $this !== $value && !is_scalar($value)) {
            throw new BadRequestException(sprintf('Input value "%s" contains a non-scalar value.', $key));
        }

set function - vendor/symfony/http-foundation/InputBag.php:77

        if (null !== $value && !is_scalar($value) && !\is_array($value) && !$value instanceof \Stringable) {
            throw new \InvalidArgumentException(sprintf('Excepted a scalar, or an array as a 2nd argument to "%s()", "%s" given.', __METHOD__, get_debug_type($value)));
        }

How to reproduce

Set a array _GET or _POST value and try to get the same _GET or POST key

Possible Solution

Add the same check that's in the set function also in the get function

Additional Context

No response