session_start never initiated, still session starts with $_SESSION[]

php.ini session.auto_start = 0
I never initiated session_start(), print_r($_SESSION) return null but as soon I make $_SESSION['var'] = 'content'; the session array magically shows in print_r

Is this normal?

 

of course it is.

The same as setting $var['x'] = 'y'; print_r($var); => shows array info

 

I agree, its just a localy set variable, but will not be taken to a next page... as when you start with session_start(); these variables will be saved and available on the next page.

 

Ah, I know what happened, the data probably is coming from the cookie I have set.
It reads the cookie and fills the $_SESSION array once in the condition it's empty, but since the SESSION never saves, the cookie keeps filling it on every page

 

The array exists, but it's null (never written to) until you write to it. That's normal for a superglobal.