Make sure clean URLs are off and that all errors, notices and warnings are displayed (otherwise you won't see this error). Log in as a user. Don't log out, but go to the home URL without any query.
Expected
No error, homepage loads
Actual
A notice is displayed about a missing index q
Notes
$_GET['q'] is used without checking whether it's empty or not, or even set in hook_boot
Test
Make sure clean URLs are off and that all errors, notices and warnings are displayed (otherwise you won't see this error). Log in as a user. Don't log out, but go to the home URL without any query.
Expected
No error, homepage loads
Actual
A notice is displayed about a missing index q
Notes
$_GET['q'] is used without checking whether it's empty or not, or even set in hook_boot