Error [RuntimeException] Could not scan for classes inside "database/seeds"

Question

I have a problem running composer update

the same thing happens with other installation commands too

Error:

[RuntimeException] Could not scan for classes inside "database/seeds" which does not appear to be a file nor a folder

How can I solve this error? try, running composer install and it doesn't work either

{
"name": "laravel/laravel",
"type": "project",
"description": "The Laravel Framework.",
"keywords": [
    "framework",
    "laravel"
],
"license": "MIT",
"require": {
    "php": "^7.2.5",
    "fideloper/proxy": "^4.2",
    "fruitcake/laravel-cors": "^1.0",
    "guzzlehttp/guzzle": "^6.3",
    "laravel/framework": "^7.0",
    "laravel/tinker": "^2.0",
    "laravel/ui": "^2.0"
},
"require-dev": {
    "facade/ignition": "^2.0",
    "fzaninotto/faker": "^1.9.1",
    "mockery/mockery": "^1.3.1",
    "nunomaduro/collision": "^4.1",
    "phpunit/phpunit": "^8.5"
},
"config": {
    "optimize-autoloader": true,
    "preferred-install": "dist",
    "sort-packages": true
},
"extra": {
    "laravel": {
        "dont-discover": []
    }
},
"autoload": {
    "psr-4": {
        "App\\": "app/"
    },
    "classmap": [
        "database/seeds",
        "database/factories"
    ]
},
"autoload-dev": {
    "psr-4": {
        "Tests\\": "tests/"
    }
},
"minimum-stability": "dev",
"prefer-stable": true,
"scripts": {
    "post-autoload-dump": [
        "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump",
        "@php artisan package:discover --ansi"
    ],
    "post-root-package-install": [
        "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
    ],
    "post-create-project-cmd": [
        "@php artisan key:generate --ansi"
    ]
}
}

Answer 1

Change composer autoload to

"autoload": {
        "psr-4": {
            "App\\": "app/",
            "Database\\Factories\\": "database/factories/",
            "Database\\Seeders\\": "database/seeders/"
        }
    }

In Laravel 8 two directories Factory and seeders have Namespace. While in Laravel 7 it's still using the class-map to load them.

First, check your classes if they are using namespace then use psr4 autoload otherwise you can use class-map;