How does Laravel handle serialization of closures in configuration files

- When running `php artisan config:cache`, Laravel checks if the configuration files are serializable. If a Closure is found, it throws a `LogicException` with the message "Your configuration files are not serializable."[1][2]

- This is a limitation in Laravel by design, as serializing Closures is considered a hack. It's better to avoid using Closures in configuration files altogether.[1]

- To work around this limitation, you can replace any Closures in your configuration files with regular functions or class methods that can be serialized properly.[1][2]

- For example, instead of using a Closure, you can define a static method on a class and reference it in the configuration file like this:

php
'before_send' => [MyClass::class, 'myMethod'],

- Where `MyClass::myMethod` is a regular PHP callable that can be serialized without issues.[1]

- Another option is to convert any objects in the configuration to arrays using `toArray()` before caching the configuration.[2]

- Once the configuration is cached, Laravel will not load the `.env` file during requests. So you should avoid using `env()` in configuration files and instead set the values directly.[3]

In summary, Laravel enforces that configuration files be serializable by disallowing Closures. This is a design choice to avoid potential issues. The recommended approach is to use regular functions or class methods instead of Closures in configuration.