Array to string conversion with cache

I’m noticing some errors in my logs when using DeviceDetector, both related to caching and PHP warnings. The errors appear when the package tries to save regex data to Redis or process certain vendor fragments.

[2025-08-25T13:18:26.656569+00:00] cache.WARNING: Failed to save key "DeviceDetector-646regexes-console" of type array: protocol error, got 'a' as reply type byte  {"key":"DeviceDetector-646regexes-console","exception":"[object] (RedisException(code: 0): protocol error, got 'a' as reply type byte\\n at /home/bas/app_1e8a7d42-ba90-4f14-bc0b-0ae8202e27ba/vendor/symfony/cache/Traits/Redis6Proxy.php:254)","cache-adapter":"Symfony\\\\Component\\\\Cache\\\\Adapter\\\\RedisAdapter"} []
[2025-08-25T13:18:26.657008+00:00] cache.WARNING: Failed to save key "console646-all" of type string: protocol error, got '"' as reply type byte  {"key":"console646-all","exception":"[object] (RedisException(code: 0): protocol error, got '\\"' as reply type byte\\n at /home/bas/app_1e8a7d42-ba90-4f14-bc0b-0ae8202e27ba/vendor/symfony/cache/Traits/Redis6Proxy.php:254)","cache-adapter":"Symfony\\\\Component\\\\Cache\\\\Adapter\\\\RedisAdapter"} []
[2025-08-25T13:18:26.657808+00:00] cache.WARNING: Failed to save key "DeviceDetector-646regexes-carbrowser" of type array. {"key":"DeviceDetector-646regexes-carbrowser","exception":null,"cache-adapter":"Symfony\\\\Component\\\\Cache\\\\Adapter\\\\RedisAdapter"} []
[2025-08-25T13:18:28.073341+00:00] cache.WARNING: Failed to save key "camera646-all" of type string. {"key":"camera646-all","exception":null,"cache-adapter":"Symfony\\\\Component\\\\Cache\\\\Adapter\\\\RedisAdapter"} []
[2025-08-25T13:18:28.075060+00:00] cache.WARNING: Failed to save key "DeviceDetector-646regexes-portablemediaplayer" of type array. {"key":"DeviceDetector-646regexes-portablemediaplayer","exception":null,"cache-adapter":"Symfony\\\\Component\\\\Cache\\\\Adapter\\\\RedisAdapter"} []
[2025-08-25T13:18:28.075574+00:00] php.ERROR: Warning: Array to string conversion {"exception":"[object] (ErrorException(code: 0): Warning: Array to string conversion at /home/bas/app_1e8a7d42-ba90-4f14-bc0b-0ae8202e27ba/vendor/matomo/device-detector/Parser/VendorFragment.php:44)"} []
[2025-08-25T13:18:28.076203+00:00] php.ERROR: Warning: Array to string conversion {"exception":"[object] (ErrorException(code: 0): Warning: Array to string conversion at /home/bas/app_1e8a7d42-ba90-4f14-bc0b-0ae8202e27ba/vendor/matomo/device-detector/Parser/VendorFragment.php:44)"} []
[2025-08-25T13:18:28.076450+00:00] php.ERROR: Warning: Array to string conversion {"exception":"[object] (ErrorException(code: 0): Warning: Array to string conversion at /home/bas/app_1e8a7d42-ba90-4f14-bc0b-0ae8202e27ba/vendor/matomo/device-detector/Parser/VendorFragment.php:44)"} []
[2025-08-25T13:18:28.076631+00:00] php.ERROR: Warning: Array to string conversion {"exception":"[object] (ErrorException(code: 0): Warning: Array to string conversion at /home/bas/app_1e8a7d42-ba90-4f14-bc0b-0ae8202e27ba/vendor/matomo/device-detector/Parser/VendorFragment.php:44)"} []

Environment:

Symfony 7.3
Redis : 8.0.2
PHP 8.4
matomo/device-detector version: 6.4.6

Start by reading Parser/VendorFragment.php at line 44 and compare that warning with the Redis cache failures reported from Symfony\Component\Cache\Traits\Redis6Proxy.php at line 254. Reproduce the reported environment if possible, then determine whether the vendor-fragment warning and cache errors are related; done means the reported warnings and failed cache saves no longer occur for the affected inputs.