💥 use Dotenv::createImmutable()

[QWp6t]

This has been brought up a few times internally and in the comments in this repo.

Here's an example scenario in a multithreaded environment:

Putenv and Getenv are not thread-safe. This is probably the cause of your issue.

What happens is the following:
1st request: variables are not there -> load
2nd request: variables are there -> do not load
1st request: ends, cleans up variables
2nd request: use variable -> does not exist anymore, cleaned up by 1st request

h/t vlucas/phpdotenv#248 (comment)

The rest of the PHP community has largely moved away from putenv() and getenv() due to this limitation, and it's the reason why vlucas/phpdotenv moved away from it as a default and advises against it in their readme.

Using getenv() and putenv() is strongly discouraged due to the fact that these functions are not thread safe