TIL: OpenAPI - Value expected to be 'array', but 'array' given.

OpenAPI - Value expected to be ‘array’, but ‘array’ given.

Today I learned, with league/openapi-psr7-validator array is not array - as in PHP.

This is a real array:

$array = [
    0 => [ 'id' => 'zero' ],
    1 => [ 'id' => 'one' ],
    2 => [ 'id' => 'two' ]
];

This is a list/associative array:

$array = [
    1 => [ 'id' => 'one' ],
    2 => [ 'id' => 'two' ]
];

This means, if you define your property like this:

#[OA\Property(items: new OA\Items(ref: YourData::class))]
public array $payload

And assign an associative array, you will get a validation error:

Value expected to be 'array', 'array' given.

Because league/openapi-psr7-validator checks this like so:

// vendor/league/openapi-psr7-validator/src/Schema/Keywords/Type.php:62
if (! is_array($data) || ArrayHelper::isAssoc($data)) {
    break;
}

One solution, depending on your situation and actual code could be:

$data = array_values($data);