Proper printing for wildcards

Signed-off-by: Hasan Turken <turkenh@gmail.com>

pkg/fieldpath/fieldpath.go

@@ -78,7 +78,7 @@ func (sg Segments) String() string {
 	for _, s := range sg {
 		switch s.Type {
 		case SegmentField:
-			if strings.ContainsRune(s.Field, period) {
+			if s.Field == wildcard || strings.ContainsRune(s.Field, period) {
 				b.WriteString(fmt.Sprintf("[%s]", s.Field))
 				continue
 			}
@@ -138,6 +138,8 @@ const (
 	period       = '.'
 	leftBracket  = '['
 	rightBracket = ']'
+
+	wildcard = "*"
 )
 
 type itemType int

pkg/fieldpath/fieldpath_test.go

@@ -56,6 +56,15 @@ func TestSegments(t *testing.T) {
 			},
 			want: "data[.config.yml]",
 		},
+		"Wildcard": {
+			s: Segments{
+				Field("spec"),
+				Field("containers"),
+				FieldOrIndex("*"),
+				Field("name"),
+			},
+			want: "spec.containers[*].name",
+		},
 	}
 
 	for name, tc := range cases {

pkg/fieldpath/paved.go

@@ -157,7 +157,7 @@ func expandWildcards(data interface{}, segments Segments) ([]Segments, error) {
 	it := data
 	for i, current := range segments {
 		// wildcards are regular fields with "*" as string
-		if current.Type == SegmentField && current.Field == "*" {
+		if current.Type == SegmentField && current.Field == wildcard {
 			switch mapOrArray := it.(type) {
 			case []interface{}:
 				for ix := range mapOrArray {

pkg/fieldpath/paved_test.go

@@ -942,7 +942,7 @@ func TestExpandWildcards(t *testing.T) {
 			path:   "spec.containers[0].name[*]",
 			data:   []byte(`{"spec":{"containers":[{"name":"cool"}]}}`),
 			want: want{
-				err: errors.Wrapf(errors.Errorf("%q: unexpected wildcard usage", "spec.containers[0].name"), "cannot expand wildcards for segments: %q", "spec.containers[0].name.*"),
+				err: errors.Wrapf(errors.Errorf("%q: unexpected wildcard usage", "spec.containers[0].name"), "cannot expand wildcards for segments: %q", "spec.containers[0].name[*]"),
 			},
 		},
 		"NotAnArray": {