I'm facing an issue with MAMP,
Whatever error type I get in PHP (notice, fatal etc...), MAMP returns a 500 Internal error, even when I put the following at the beginning of my script :
error_reporting(E_ALL);
ini_set('display_errors', 'On');
Anyway, I found the solution myself.
I had to directly set 'display_errors' to 'On' in the php.ini file.
It didn't work just by adding these lines in my script.