symfony: error on install --no-dev --optimize-autoloader, cache-clear

Symfony version(s) affected: 4.2.1

Description
When preparing for deployment, running composer install --no-dev --optimize-autoloader will throw error: Script cache:clear returned with error code 255 if "symfony/dotenv": "^4.0" is NOT on the required section of composer.json.

I do not plan to use .env on production and I am already running into issues on the production environment that may, or may not, be related to this.

There, on the production environment, I have added the env variables to index.php and deleted the .env files.

How to reproduce
Below is the code for composer.json BEFORE moving dotenv to require. Otherwise, APP-ENV=prod on .env. Of course, should run composer install --no-dev --optimize-autoloader.

     "type": "project",
"license": "proprietary",
"require": {
    "php": "^7.2.1",
    "ext-iconv": "*",
    "beberlei/DoctrineExtensions": "^1.1",
    "doctrine/doctrine-migrations-bundle": "^1.3",
    "friendsofsymfony/user-bundle": "^2.1",
    "sensio/framework-extra-bundle": "^5.1",
    "stof/doctrine-extensions-bundle": "^1.3",
    "symfony/asset": "^4.0",
    "symfony/console": "^4.0",
    "symfony/debug-pack": "*",
    "symfony/expression-language": "^4.0",
    "symfony/flex": "^1.0",
    "symfony/form": "^4.0",
    "symfony/framework-bundle": "^4.0",
    "symfony/monolog-bundle": "^3.1",
    "symfony/orm-pack": "^1.0",
    "symfony/process": "^4.0",
    "symfony/security-bundle": "^4.0",
    "symfony/serializer-pack": "*",
    "symfony/swiftmailer-bundle": "^3.1",
    "symfony/translation": "^4.0",
    "symfony/twig-bundle": "^4.0",
    "symfony/validator": "^4.0",
    "symfony/web-link": "^4.0",
    "symfony/yaml": "^4.0"
},
"require-dev": {
    "symfony/browser-kit": "^4.0",
    "symfony/css-selector": "^4.0",
    "symfony/maker-bundle": "^1.5",
    "symfony/phpunit-bridge": "^4.0",
    "symfony/profiler-pack": "*",
    "symfony/web-server-bundle": "^4.0",
    "symfony/dotenv": "^4.0"
},
"config": {
    "preferred-install": {
        "*": "dist"
    },
    "sort-packages": true
},
"autoload": {
    "psr-4": {
        "App\\": "src/"
    }
},
"autoload-dev": {
    "psr-4": {
        "App\\Tests\\": "tests/"
    }
},
"replace": {
    "symfony/polyfill-iconv": "*",
    "symfony/polyfill-php71": "*",
    "symfony/polyfill-php70": "*",
    "symfony/polyfill-php56": "*"
},
"scripts": {
    "auto-scripts": {
        "cache:clear": "symfony-cmd",
        "assets:install --symlink --relative %PUBLIC_DIR%": "symfony-cmd"
    },
    "post-install-cmd": [
        "@auto-scripts"
    ],
    "post-update-cmd": [
        "@auto-scripts"
    ]
},
"conflict": {
    "symfony/symfony": "*"
},
"extra": {
    "symfony": {
        "id": "01C7GQTT5A95EBYYFAVQ47GFDB",
        "allow-contrib": false
    }
}

}

Possible Solution

Additional context