[5.2] Make custom validation rules to be dependent rules

[uxweb]

This little contribution allows custom validation rules to be dependent on other fields.

This will allow to create a rule like this:

First Field should be Greater than Second Field:

'things.*.first_field' => 'greater:things.*.second_field'

This means that the * in the parameter of the rule (the other field) will be resolved as keys.

Right now there is no way to tell to the validator that a custom extension should be dependent, so it will not resolve the keys from the dependent field.

Letting the validator resolve this keys, will make a breeze to do this kind of custom validator:

Validator::extend('greater', function($attribute, $value, $parameters, $validator) {
    $other = Arr::get($validator->getData(), $parameters[0]);

    return $value >= $other;
}, null, true);

Validator::extendImplicit('greater', function($attribute, $value, $parameters, $validator) {
    $other = Arr::get($validator->getData(), $parameters[0]);

    return $value >= $other;
}, null, true);

// The last parameter on the extend and extendImplicit method tells that this is a dependent rule.
// By default is false to get the normal behavior.

Now we can create implicit and explicit custom validation rules that can be dependent on other field.

[themsaid]

@uxweb Since you're changing the Factory::extend() method signature I believe this should be submitted to 5.3 instead.

I also believe it's better that you include a test in your PR, which will help others understand the issue easily as well as prevent it from appearing again in the future after any change.

[uxweb]

@themsaid Sure, i'll try to add a test 👍, thanks

[taylorotwell]

Holding off on this implementation for now.

[briano-jabico]

@taylorotwell Is something like this planned for 5.3.x or 5.4? As far as I know, this is still not possible.

I'm making a budget editor where a user can edit many line_items at once, and I'd like to add a required_if_attribute validation rule to allow me to say that payment_date is required if the total is > $1,000. There's a few other ways I could do this, but none as reusable.

Thanks in advance!

[neilcrookes]

I too would like to be able to create a custom validation rule for array data, that depends on the value of another field in the array.

E.g. consider a list of from and to time fields, for a series of dates.

The data would look as follows:

data = [
    dates => [
        2017-04-15 => [from => 09:00, to => 17:00],
        2017-04-16 => [from => 09:00, to => 17:00],
        2017-04-17 => [from => 09:00, to => 17:00],
        2017-04-18 => [from => 09:00, to => 17:00],
    ]
]

It would be great if we could write a rule like:

rules = [
    dates.*.to => time_after:dates.*.from
]

But since the custom validation rule is not one of dependentRules, the asterisk in the parameters sent to the custom rule doesn't get replaced with the key.

[pavel-mironchik]

@briano-jabico look at 5.4.18 - #18654