QueryCache returns __PHP_Incomplete_Class on Laravel 13

[zebamba]

After upgrading our application framework from Laravel 12 to Laravel 13, using Redis as the backing store for Lighthouse's query cache query_cache.mode = 'store', requests fail with the following type error:

{
    "errors": [
        {
            "message": "Internal server error",
            "extensions": {
                "debugMessage": "Nuwave\\Lighthouse\\Cache\\QueryCache::fromStoreOrParse(): Return value must be of type GraphQL\\Language\\AST\\DocumentNode, __PHP_Incomplete_Class returned",
                "file": "/var/www/html/vendor/nuwave/lighthouse/src/Cache/QueryCache.php",
                "line": 84,
                "trace": [
                    {
                        "file": "/var/www/html/vendor/nuwave/lighthouse/src/Cache/QueryCache.php",
                        "line": 72,
                        "call": "Nuwave\\Lighthouse\\Cache\\QueryCache::fromStoreOrParse()"
                    },
                    {
                        "file": "/var/www/html/vendor/nuwave/lighthouse/src/GraphQL.php",
                        "line": 287,
                        "call": "Nuwave\\Lighthouse\\Cache\\QueryCache::fromCacheOrParse()"
                    },
....

Steps to reproduce

• Upgrade Laravel application to Laravel 13.
• Set up a dedicated cache store in config/cache.php enabling serializable_classes:

'graphql_cache' => array_merge([
    'driver' => env('CACHE_STORE', 'database'),
    'serializable_classes' => true,
], env('CACHE_STORE') === 'database' ? [
    'table' => 'cache',
    'connection' => null,
] : []),

• Ensure the underlying redis driver configuration in config/cache.php also includes 'serializable_classes' => true:

'redis' => [
    'driver' => 'redis',
    'connection' => env('REDIS_CACHE_CONNECTION', 'default'),
    'lock_connection' => env('REDIS_CACHE_LOCK_CONNECTION', 'default'),
    'serializable_classes' => true,
],

• Configure Lighthouse to use the store in config/lighthouse.php

'query_cache' => [
    'enable' => true,
    'store' => 'graphql_cache',
    'mode' => 'store',
],

• Execute any valid GraphQL query against the application.
• Trigger a second request with the same query so it hits the Redis cache store.

Expected behavior / Solution

Expected behavior: Lighthouse should successfully retrieve and unserialize the cached GraphQL\Language\AST\DocumentNode instance from the Redis store without throwing a type error.

PHP Version 8.4.23
Lighthouse Version 6.66.0