make function stable

Author: stivenbb

expr/func_keeplastvalue.go

@@ -25,7 +25,9 @@ func (s *FuncKeepLastValue) Signature() ([]Arg, []Arg) {
 				opt: true,
 				args: []Arg{
 					ArgInt{val: &s.limit},
-					ArgString{val: &stub}, // Allow user to specify 'INF' as value. if so, will fall back to maxInt
+					// Allow user to specify 'INF' as value. if so, will fall back to maxInt
+					// Ignores any other strings (just like Graphite)
+					ArgString{val: &stub},
 				},
 			},
 		},

expr/funcs.go

@@ -69,7 +69,7 @@ func init() {
 		"highestCurrent":    {NewHighestLowestConstructor("current", true), true},
 		"highestMax":        {NewHighestLowestConstructor("max", true), true},
 		"isNonNull":         {NewIsNonNull, true},
-		"keepLastValue":     {NewKeepLastValue, false},
+		"keepLastValue":     {NewKeepLastValue, true},
 		"lowest":            {NewHighestLowestConstructor("", false), true},
 		"lowestAverage":     {NewHighestLowestConstructor("average", false), true},
 		"lowestCurrent":     {NewHighestLowestConstructor("current", false), true},