Allows you to specify .ConditionlessWhen(string.IsNullOrEmpty(query)) on a function score query to prevent functions to be applied in case of an empty query or fixed references inside the functions

Author: Mpdreamz

src/Nest/DSL/Query/FunctionScoreQueryDescriptor.cs

@@ -98,17 +98,26 @@ public class FunctionScoreQueryDescriptor<T> : IFunctionScoreQuery where T : cla
 
 		string IQuery.Name { get; set; }
 
+		private bool _forcedConditionless = false;
+
 		bool IQuery.IsConditionless
 		{
 			get
 			{
-				return (Self.Query == null || Self.Query.IsConditionless)
+				return _forcedConditionless || ((Self.Query == null || Self.Query.IsConditionless)
 					&& Self.RandomScore == null 
 					&& Self.ScriptScore == null 
-					&& !Self.Functions.HasAny();
+					&& !Self.Functions.HasAny());
 			}
 		}
 
+		public FunctionScoreQueryDescriptor<T> ConditionlessWhen(bool isConditionless)
+		{
+			this._forcedConditionless = isConditionless;
+			return this;
+		}
+
+
 		public FunctionScoreQueryDescriptor<T> Name(string name)
 		{
 			Self.Name = name;