Description:
------------
The warning appears if you try to call file inside the file, for example:  
/home/public_html/test/test.php/.infuso - if test.php is file you have warning but everything is ok if test.php is name of folder.

P.s. PHP Version 5.4.27

Test script:
---------------
<?php
ini_set("display_errors",1);
    if(file_exists("/home/public_html/test/test.php/.infuso")){
        echo "File exists";
    }else{
        echo "File does not exist";
    }
?>

Expected result:
----------------
file_exists should return a FALSE and you should read "File does not exist".

Actual result:
--------------
Warning: file_exists(): open_basedir restriction in effect. File(/home/public_html/test/test.php/.infuso) is not within the allowed path(s): (/home:.) in /home/public_html/test/test.php/.infuso on line 4