Empty string passes 'array' validation rule

[refi93]

• Laravel Version: 5.4.6
• PHP Version: 7.1.2

Description:

The validation rule for an array allows for an empty string which seems weird to me, see the following example:

Steps To Reproduce:

$ php artisan tinker
>>> (\Validator::make( ['field' => ""], ['field' => 'array'] ))->passes();
=> true

Tested with:

$ php artisan --version
Laravel Framework Lumen (5.4.6) (Laravel Components 5.4.*)

[marconi1992]

I think because laravel validation handle the null, "", [] like empty values.
https://github.com/laravel/framework/blob/5.4/src/Illuminate/Validation/Validator.php#L334

Therefore you should add the required rule to validate empty values in the field, I'm don't sure if is a weird behavior or if is expected.

[refi93]

@marconi1992 yes, but I don't think that "" is a valid php array which is stated in the documentation. I don't know the exact definition of a "valid php array" but if we assume that an empty string was a valid php array, I can't understand the following behavior:

$ php artisan tinker
>>> is_array("");
=> false
>>> is_array([]);
=> true

Due to this behavior my application fails when I pass that field to a function that expects an array. The problem is that for my use case, an empty array is valid, but not an empty string, that's why the "required" rule does not fit my needs. Basically I would like to have a field that must be present and it must be a valid array, regardless of its size.

I tried the rule "present|array" and it works for me, except that one case - when the field is an empty string, since the validator considers it to be valid.

Another attempt was "present|array|not_in:,", but the not_in rule apparently does not accept an empty string as a possible value.

[refi93]

@marconi1992 ok, I see - the isValidatable method, as you pointed out, prevents the empty string from being validated, but personally, I find it quite weird.

At least, it would be nice to put a warning in the documentation, because if this is really the desired behavior, then I find the specification of the array rule stating that "The field under validation must be a PHP array." to be misleading, as you can see from the example above.

[ConnorVG]

Maybe isValidatable should have a strict check option for null?

[trevorgehman]

It's been this way for a long time, that an empty string is not validated unless there is a required or similar rule on it.

This situation was changed somewhat by the ConvertEmptyStringsToNull middleware which was introduced in 5.4. If you use that middleware, it avoids this headache/confusion, since an empty string will be converted to null and fail any validation check like array, integer, etc.

[ecrmnn]

For anyone coming here in the future, I had a similar problem and was able to solve it like this:

If replies was passed as an empy array [] I wanted it to fail validation.
By adding required on both replies and replies.* I was able to achieve this.

[
    'replies' => [
        'required',
    ],
    'replies.*' => [
        'required',
    ],
]

⚠️ Caveat: this will be two different kind of errors depending on your data.
Either replies or replies.* will be in your error message bag.

[skillaug]

It's been this way for a long time, that an empty string is not validated unless there is a required or similar rule on it.

This situation was changed somewhat by the ConvertEmptyStringsToNull middleware which was introduced in 5.4. If you use that middleware, it avoids this headache/confusion, since an empty string will be converted to null and fail any validation check like array, integer, etc.

enable ConvertEmptyStringsToNull middleware and it also fails on String, it's a bad solution for me, I can't save an empty string into string properties

[onmigregor]

hi, I just need know if was fixed

I have an array, which can be
array:3 [ 0 => "190" 1 => "56" 2 => "127" 3 => "50" ]

or

array:3 [ 0 => "" 1 => "" 2 => "" 3 => "" ]

But no this way
array:3 [ 0 => "" 1 => "56" 2 => "20" 3 => "" ]

I have been trying validator using validation combinations without success, does anyone know what is needed