如何创建一个“ OR” Symfony验证器约束

Question

How would one go about creating a Symfony 4.2 constraint that validates multiple batches of constraints, but fails only if all of them fail?

Here's my use case.

I want to validate a variable that can be either an object of specific class, or an array representing an object of the same class. I would then have 2 cases:

1. I would want to validate against Type(type=array) constraint and then a Collection(fields={...}) constraint to ensure this is an array with proper structure that I can then deserialize and get the object;
2. or I would want to validate against Type(type=MyClassName) .

So, the final constraint should succeed if either case 1 or case 2 succeeds, and should fail only if both fail (say a string is passed).

I feel groups could be useful somehow, but I am not entirely sure how exactly to use them in this case.

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I already have an idea how to implement this, but somehow it fails and I can't figure out why:

$violations1 = $this->context->getValidator()->validate($value, $constraints1);
$violations2 = $this->context->getValidator()->validate($value, $constraints2);

// Check both violations and if at least one of them is empty - succeed.
// If all of them fail, copy violations to the current context.

As you can see I would validate the value against $constraints1 which is an array of constraints to check if the value is a valid array. Then I would validate the value against $constraints2 which is a different array of constraints that checks if the value is an object of specific class.

At this point I want to just copy the violations and fail, or succeed if either $violations1 or $violations2 are empty.

The problem is, that for some reason $violations2 is always empty, even if it should fail. As if the validator refuses to validate the same value twice, even if it's against a different set of constraints. Is this true and how to circumvent it?

Answer 1

You can use the expression constraint . It allows to combine multiple tests with 'or'.