Let's not be grouchy about this. Empty ins are probably uncommon and it's

foolish to complicate a bunch of client code. Either we'll do some magical
optimization on the Depot side and not even send queries to the server that we
know can't match anything, or we'll just suck it up and occasionally send a
query to the database that we know will match no rows. C'est la vie.

src/java/com/samskivert/depot/operator/In.java

@@ -39,10 +39,6 @@ public class In
 
     public In (ColumnExp column, Comparable<?>... values)
     {
-        if (values.length == 0) {
-            log.warning("Grouchily allowing empty In() operator", "column", column.name,
-                        new Exception());
-        }
         _column = column;
         _values = values;
     }