Split of "" should be empty. Length of empty array should be 0

config/interpolate_funcs.go

@@ -251,6 +251,9 @@ func interpolationFuncSplit() ast.Function {
 		Callback: func(args []interface{}) (interface{}, error) {
 			sep := args[0].(string)
 			s := args[1].(string)
+			if s == "" {
+				return NewStringList([]string{}).String(), nil
+			}
 			return NewStringList(strings.Split(s, sep)).String(), nil
 		},
 	}

config/interpolate_funcs_test.go

@@ -312,6 +312,11 @@ func TestInterpolateFuncLength(t *testing.T) {
 			},
 
 			// Lists
+			{
+				`${length(split(",", ""))}`,
+				"0",
+				false,
+			},
 			{
 				`${length(split(",", "a"))}`,
 				"1",
@@ -352,7 +357,7 @@ func TestInterpolateFuncSplit(t *testing.T) {
 
 			{
 				`${split(",", "")}`,
-				NewStringList([]string{""}).String(),
+				NewStringList([]string{}).String(),
 				false,
 			},
 

config/string_list.go

@@ -53,14 +53,13 @@ func (sl StringList) Length() int {
 
 // Returns a slice of strings as represented by this StringList
 func (sl StringList) Slice() []string {
-	parts := strings.Split(string(sl), stringListDelim)
-
-	switch len(parts) {
-	case 0, 1:
+	if string(sl) == stringListDelim {
 		return []string{}
-	case 2:
+	}
+	if string(sl) == strings.Join([]string{stringListDelim, stringListDelim}, "") {
 		return []string{""}
 	}
+	parts := strings.Split(string(sl), stringListDelim)
 
 	// strip empty elements generated by leading and trailing delimiters
 	return parts[1 : len(parts)-1]

config/string_list_test.go

@@ -0,0 +1,29 @@
+package config
+
+import (
+	"testing"
+)
+
+func TestStringListLength(t *testing.T) {
+	empty := NewStringList([]string{})
+	l := empty.Length()
+	if l != 0 {
+		t.Errorf("L != 0")
+	}
+}
+
+func TestStringListSlice(t *testing.T) {
+	empty := NewStringList([]string{})
+	s := empty.Slice()
+	if len(s) != 0 {
+		t.Errorf("Empty StringList Slice not zero length")
+	}
+	oneelem_empty := NewStringList([]string{""})
+	s = oneelem_empty.Slice()
+	if len(s) != 1 {
+		t.Errorf("Stringlist of empty element not length 1")
+	}
+	if s[0] != "" {
+		t.Errorf("Stringlist of empty element first element not empty")
+	}
+}