> The problem with preview() is that it must "freeze" the query into a
> final form, as opposed to the intermediate form it uses when holding the
> query prior to execution. preview() almost goes completely through the
> actual query finalization process in order to freeze the query, so it
> can have unfortunate side effects. Probably the change is due to the
> Query call chain reorganization, needed to allow nulls in queries.
IMHO functions like preview() must not make any changes to Query object, they
must work with its copy => they should be "const". But I guess it's
impossible to _easily_ make such changes right now :(
PS Anyway, it's a strange behavior - attempt to "freeze" query, cause query
corruption. I'll try to find a decision.