Warning: Undefined array key "APP_ENV"

[lance1572]

Describe the bug

Getting a warning "Undefined array key "APP_ENV" from

PHP Warning: Undefined array key "APP_ENV" in /Users/user/Desktop/new-app/vendor/leafs/mvc-core/src/Core.php on line 527

A clear and concise description of what the bug is.

To Reproduce

Steps to reproduce the behavior:

1. Go to 'https://leafphp.dev/learn/mvc.html'

2. leaf create my-app --mvc

3. cd my-app
   php leaf serve

4. Page Loads with Warning: Undefined array key "APP_ENV" in /Users/user/Desktop/new-app/vendor/leafs/mvc-core/src/Core.php on line 527

I see another closed issue similar to this.

#308

I've followed the steps in that issue by running composer update and replacing the index.php with the code supplied. Im not sure what is happening. However, if I add an isset, the warning goes away.

Core.php line 527

if (isset($_ENV['APP_ENV']) && $_ENV['APP_ENV'] !== 'production')