QueryBuilder produces invalid SQL from an empty CompositeExpression

[morozov]

Q	A
BC Break	no
Version	2.10.1

$qb = $conn->createQueryBuilder();
$qb->select('*')
    ->where($qb->expr()->andX());
echo $qb;
// SELECT * WHERE ()

[SenseException]

What's the expected behaviour for this?

[morozov]

Either a QueryException or no WHERE clause. I mostly filed it for documentation purposes. In master, I want to make the composite expression to always have at least one (or even better, two) parts. It shouldn't be possible to instantiate an empty object in the first place.

[morozov]

Fixed by #3868.