Don't freak out on empty In()'s, just scold the developer.

src/java/com/samskivert/depot/impl/BuildVisitor.java

@@ -220,6 +220,11 @@ public abstract class BuildVisitor implements ExpressionVisitor
 
     public void visit (In in)
     {
+        // if the In() expression is empty, replace it with a 'false'
+        if (in.getValues().length == 0) {
+            new ValueExp(false).accept(this);
+            return;
+        }
         in.getColumn().accept(this);
         _builder.append(" in (");
         Comparable<?>[] values = in.getValues();

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

@@ -31,6 +31,8 @@ import com.samskivert.depot.expression.SQLExpression;
 import com.samskivert.depot.impl.ExpressionVisitor;
 import com.samskivert.util.Tuple;
 
+import static com.samskivert.Log.log;
+
 /**
  * A convenient container for implementations of conditional operators.  Classes that value brevity
  * classes that feel otherwise will use Conditionals.Equals() and Conditionals.In().
@@ -195,7 +197,7 @@ public abstract class Conditionals
         public In (ColumnExp column, Comparable<?>... values)
         {
             if (values.length == 0) {
-                throw new IllegalArgumentException("In() condition needs at least one value.");
+                log.warning("Grouchily allowing empty In() operator", "column", column.name);
             }
             _column = column;
             _values = values;