Regex validator throws exception on invalid input

[emil-nasso]

I have this example, which i use in a small json-api where i use the form component to handle requests and validation.

->add('account', 'text', [
                'constraints' => [
                    new NotBlank(),
                    new Type('string'),
                    new Regex("/^XX\d+$/i")
                ]
            ])

I have a form field for an accountname. The format of this name is XX1234.

The validation above works great if the data being validated is a string. If i pass in an array instead of the string i will get an exception that is originating from here:

https://github.com/symfony/symfony/blob/2.8/src/Symfony/Component/Validator/Constraints/RegexValidator.php#L43

In my opinion the validation should just fail here instead of throwing an exception. I pass an array in, and try to run an regexp on it. It seems obvious to me that something is wrong with the input data then and the validation should fail.

Other validation constraints seems to work this way. Look at this example:

->add('disksize', 'text', [
                'constraints' => [
                    new NotBlank(),
                    new Type('numeric'),
                    new Range(['min' => 10, 'max' => 200])
                ]
            ])

This works. I get an validation error and no exceptions. Other validations contraints, like Length seems to have the same problem as Regex

I think it would be great if all constraints just failed if they were passed an array if they cant handle an array. Or is there something i am overseeing?

Is there some way i can work around this to make it fail validation if i pass in an array?

[Tobion]

Ref. #5334, #4102, #13804 etc

[xabbuh]

Does it make sense to fix this per validator or does it need to be solved in the validation extension of the Form component?

[machee]

Similarly, Collection should just fail instead of throwing an exception when not passed an array/ArrayAccess/Traversable.

[xabbuh]

By the way, what I don't understand here: Shouldn't such a request already fail before the validation when the submitted data are mapped to the form? I mean how should an array be mapped to a TextType?

[emil-nasso]

I agree, that would make more sense.

[xabbuh]

#20935 when being applied more generally should fix this issue.

[stoccc]

I think that a validator should fail validation if it not receives the expected format; it should not throw an exception..

The same thing happens in LengthValidator here https://github.com/symfony/validator/blob/master/Constraints/LengthValidator.php#L37 and in many other validators. What is the reason of this choice?

[yceruto]

Also related to #13560

[xabbuh]

Thank you all for the discussion. I am going to close here in favour of #12312.