パッケージ設定のマージとキャッシュ

<?php

namespace Acme\Courier;

use Illuminate\Support\ServiceProvider;

class CourierServiceProvider extends ServiceProvider
{
    public function register(): void
    {
        $this->mergeConfigFrom(
            __DIR__.'/../config/courier.php', 'courier'
        );
    }

    public function boot(): void
    {
        $this->publishes([
            __DIR__.'/../config/courier.php' => config_path('courier.php'),
        ], 'courier-config');
    }
}

php artisan vendor:publish --tag=courier-config

<?php

$defaults = [
    'enabled' => true,
    'transport' => [
        'timeout' => 10,
        'retries' => 3,
    ],
];

$overrides = [
    'transport' => [
        'timeout' => 30,
    ],
];

$config = array_merge($defaults, $overrides);

var_export($config);

array (
  'enabled' => true,
  'transport' =>
  array (
    'timeout' => 30,
  ),
)

public function register(): void
{
    $this->replaceConfigRecursivelyFrom(
        __DIR__.'/../config/courier.php', 'courier'
    );
}

$config = array_replace_recursive($defaults, $overrides);

var_export($config);

array (
  'enabled' => true,
  'transport' =>
  array (
    'timeout' => 30,
    'retries' => 3,
  ),
)

<?php

$defaults = ['channels' => ['mail', 'database']];
$overrides = ['channels' => ['slack']];

$config = array_replace_recursive($defaults, $overrides);

var_export($config['channels']);

array (
  0 => 'slack',
  1 => 'database',
)

php artisan config:cache