feat: allow getSingleTag to return later occurrences

main.go

@@ -48,7 +48,7 @@ func main() {
 			if query == "" {
 				fmt.Println(string(val))
 			} else {
-				tag, err := getSingleTag(images, query)
+				tag, err := getSingleTag(images, query, 0)
 
 				if err != nil {
 					log.Fatalf("Could not find image in Dockerfile: %s", query)
@@ -107,10 +107,16 @@ func getImages(commands []dockerfile.Command, unknownMarker string) []Image {
 	return images
 }
 
-func getSingleTag(images []Image, query string) (string, error) {
+func getSingleTag(images []Image, query string, occurrence int) (string, error) {
+	found := 0
+
 	for _, i := range images {
 		if i.Name == query {
-			return i.Tag, nil
+			found += 1
+
+			if found >= occurrence {
+				return i.Tag, nil
+			}
 		}
 	}
 

main_test.go

@@ -30,14 +30,21 @@ func TestParsing(t *testing.T) {
 
 func TestQuery(t *testing.T) {
 	cases := []struct {
-		query string
-		match bool
-		tag   string
+		query      string
+		occurrence int
+		match      bool
+		tag        string
 	}{
-		{query: "foo", match: false, tag: ""},
-		{query: "viaductoss/ksops", match: true, tag: "v3.0.0"},
-		{query: "golang", match: true, tag: "1.17.0-alpine"},
-		{query: "common", match: true, tag: "?"},
+		{query: "foo", occurrence: 0, match: false, tag: ""},
+		{query: "viaductoss/ksops", occurrence: 0, match: true, tag: "v3.0.0"},
+		{query: "golang", occurrence: 0, match: true, tag: "1.17.0-alpine"},
+		{query: "common", occurrence: 0, match: true, tag: "?"},
+		{query: "foo", occurrence: 1, match: false, tag: ""},
+		{query: "viaductoss/ksops", occurrence: 1, match: true, tag: "v3.0.0"},
+		{query: "golang", occurrence: 1, match: true, tag: "1.17.0-alpine"},
+		{query: "common", occurrence: 1, match: true, tag: "?"},
+		{query: "viaductoss/ksops", occurrence: 2, match: false, tag: ""},
+		{query: "common", occurrence: 3, match: true, tag: "?"},
 	}
 
 	commands, err := dockerfile.ParseFile("tests/Dockerfile.1")
@@ -49,7 +56,7 @@ func TestQuery(t *testing.T) {
 	tags := getImages(commands, "?")
 
 	for _, c := range cases {
-		result, err := getSingleTag(tags, c.query)
+		result, err := getSingleTag(tags, c.query, c.occurrence)
 
 		if c.match {
 			assert.NoError(t, err, "must match %v", c.query)