digiaonline / graphql-php

src/Validation/Rule/UniqueArgumentNamesRule.php

<?php

namespace Digia\GraphQL\Validation\Rule;

use Digia\GraphQL\Language\Node\ArgumentNode;
use Digia\GraphQL\Language\Node\DirectiveNode;
use Digia\GraphQL\Language\Node\FieldNode;
use Digia\GraphQL\Language\Node\NameNode;
use Digia\GraphQL\Language\Visitor\VisitorResult;
use Digia\GraphQL\Validation\ValidationException;
use function Digia\GraphQL\Validation\duplicateArgumentMessage;

/**
 * Unique argument names
 *
 * A GraphQL field or directive is only valid if all supplied arguments are
 * uniquely named.
 */
class UniqueArgumentNamesRule extends AbstractRule
{
    /**
     * @var NameNode[]
     */
    protected $knownArgumentNames = [];

    /**
     * @inheritdoc
     */
    protected function enterField(FieldNode $node): VisitorResult
    {
        $this->knownArgumentNames = [];

        return new VisitorResult($node);
    }

    /**
     * @inheritdoc
     */
    protected function enterDirective(DirectiveNode $node): VisitorResult
    {
        $this->knownArgumentNames = [];

        return new VisitorResult($node);
    }

    /**
     * @inheritdoc
     */
    protected function enterArgument(ArgumentNode $node): VisitorResult
    {
        $argumentName = $node->getNameValue();

        if (isset($this->knownArgumentNames[$argumentName])) {
            $this->context->reportError(
                new ValidationException(
                    duplicateArgumentMessage($argumentName),

It seems like $argumentName can also be of type null; however, parameter $argumentName of Digia\GraphQL\Validation\duplicateArgumentMessage() does only seem to accept string, maybe add an additional type check?

                    [$this->knownArgumentNames[$argumentName], $node->getName()]
                )
            );
        } else {
            $this->knownArgumentNames[$argumentName] = $node->getName();
        }

        return new VisitorResult(null);
    }
}