Symfony Validator Constraints Regex behaves differently to PHP preg_match condition

ChangeName.php

<?php

namespace Acme\PersonnelManagement\Application\Service\Person;

use Acme\Common\Domain\Model\FirstName;
use Symfony\Component\Validator\Constraints as Assert;

final class ChangeName
{
    /**
     * @var FirstName
     * @Assert\NotNull
     * @Assert\NotBlank
     * @Assert\Type(type="string")
     * @Assert\Regex(pattern="/^[\p{L}\\-\\. \']+$/u")
     */
    private $firstName;
}

NamePolicy.php

<?php

namespace Acme\Common\Domain\Model\PersonalName;

final class NamePolicy
{
    public static function isSatisfiedBy(string $name): bool
    {
        if (empty($name)) {
            return false;
        }

        // Allowed are unicode letters only and `.`, `-`, `'`, no numbers.
        if (0 === preg_match("/^[\p{L}\\-\\. \']+$/u", $name)) {
            return false;
        }

        // Continuous uppercase letters are not allowed.
        if (1 === preg_match("/[\p{Lu}]{2,}/u", $name)) {
            return false;
        }

        return true;
    }
}

NamePolicyTest.php

<?php

namespace Tests\Acme\Common\Domain\PersonalName;

use PHPUnit\Framework\TestCase;
use Acme\Common\Domain\Model\PersonalName\NamePolicy;

final class NamePolicyTest extends TestCase
{
      /** @test */
    public function hyphenSeparatedDoubleNamesAreAllowed(): void
    {
        $policy = NamePolicy::isSatisfiedBy('Hans-Werner');

        $this->assertTrue($policy);
    }
}

Came from:

• https://twitter.com/webdevilopers/status/1285854869992230912

The regex pattern for the NamePolicy l. 14 matches the asserted pattern in ChangeName command l. 14.

It works as expected in both cases for:

• "Hans Werner"
• "Hans B. Werner"
• "Hans B. Werner'X"

But not for "Hans-Werner"! The command the symfony constraint throws an error:

^ Symfony\Component\Validator\ConstraintViolationList {#383 ▼
  -violations: array:1 [▼
    0 => Symfony\Component\Validator\ConstraintViolation {#426 ▼
      -message: "Dieser Wert ist nicht gültig."
      -messageTemplate: "This value is not valid."
      -parameters: array:1 [▼
        "{{ value }}" => ""Hans-Werner""
      ]
      -plural: null
      -root: Acme\PersonnelManagement\Application\Service\Person\ChangeName {#311 ▶}
      -propertyPath: "firstName"
      -invalidValue: "Hans-Werner"
      -constraint: Symfony\Component\Validator\Constraints\Regex {#415 ▼
        +message: "This value is not valid."
        +pattern: "/^[\p{L}\\-\\. \']+$/u"
        +htmlPattern: null
        +match: true
        +normalizer: null
        +payload: null
        +"groups": array:2 [▶]
      }
      -code: "de1e3db3-5ed4-4941-aae4-59f3667cc3a3"
      -cause: null
    }
  ]
}

In how far does the Symfony Validator Constraint handle the pattern differently from preg_match?

It looks like you have to remove the "double escape" as mentioned in:

• symfony/symfony#22865
• https://stackoverflow.com/questions/44126803/symfony-regex-validator-doesnt-work-in-annotation

BEFORE:

    /**
     * @var FirstName
     * @Assert\NotNull
     * @Assert\NotBlank
     * @Assert\Type(type="string")
     * @Assert\Regex(pattern="/^[\p{L}\\-\\. \']+$/u")
     */

AFTER:

    /**
     * @var FirstName
     * @Assert\NotNull
     * @Assert\NotBlank
     * @Assert\Type(type="string")
     * @Assert\Regex(pattern="/^[\p{L}\-\. \']+$/u")
     */

Thank you @lashae & @javiereguiluz !

In addition it looks like the "double escape" in my original pattern is not required at all.

        if (1 !== preg_match("/^[\p{L}\-\. \']+$/u", $name, $matches)) {
            return false;
        }

Works fine.

Improved by @freshp:

        // Allowed are unicode letters only and `.`, `-`, `'`, no numbers.
        if (1 !== preg_match("/^[\p{L}\-\.\s\']+$/u", $name)) {
            return false;
        }