Handle more than one area label on each PR

hack/tools/release/notes.go

@@ -22,6 +22,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/json"
 	"flag"
 	"fmt"
 	"os"
@@ -105,26 +106,62 @@ func increaseDateByOneDay(date string) (string, error) {
 	return datetime.Format(layout), nil
 }
 
+const (
+	missingAreaLabelPrefix   = "MISSING_AREA"
+	areaLabelPrefix          = "area/"
+	multipleAreaLabelsPrefix = "MULTIPLE_AREAS["
+)
+
+type githubPullRequest struct {
+	Labels []githubLabel `json:"labels"`
+}
+
+type githubLabel struct {
+	Name string `json:"name"`
+}
+
 func getAreaLabel(merge string) (string, error) {
 	// Get pr id from merge commit
 	prID := strings.Replace(strings.TrimSpace(strings.Split(merge, " ")[3]), "#", "", -1)
 
-	// Get labels on the pr
-	cmd := exec.Command("gh", "api", "repos/kubernetes-sigs/cluster-api/pulls/"+prID, "--jq", ".labels[] | select(.name | contains (\"area\")) | .name") //nolint:gosec
+	cmd := exec.Command("gh", "api", "repos/kubernetes-sigs/cluster-api/pulls/"+prID)
 
 	out, err := cmd.CombinedOutput()
 	if err != nil {
-		fmt.Println("Error", err)
 		return "", err
 	}
 
-	areaLabel := string(out)
-	if areaLabel == "" {
-		return "TODO", nil
+	pr := &githubPullRequest{}
+	if err := json.Unmarshal(out, pr); err != nil {
+		return "", err
 	}
 
-	area := strings.TrimSpace(strings.Split(areaLabel, "/")[1])
-	return area, nil
+	var areaLabels []string
+	for _, label := range pr.Labels {
+		if area, ok := trimAreaLabel(label.Name); ok {
+			areaLabels = append(areaLabels, area)
+		}
+	}
+
+	switch len(areaLabels) {
+	case 0:
+		return missingAreaLabelPrefix, nil
+	case 1:
+		return areaLabels[0], nil
+	default:
+		return multipleAreaLabelsPrefix + strings.Join(areaLabels, "|") + "]", nil
+	}
+}
+
+// trimAreaLabel removes the "area/" prefix from area labels and returns it.
+// If the label is an area label, the second return value is true, otherwise false.
+func trimAreaLabel(label string) (string, bool) {
+	trimmed := strings.TrimPrefix(label, areaLabelPrefix)
+	if len(trimmed) < len(label) {
+		return trimmed, true
+	}
+
+	return label, false
 }
 
 func run() int {
@@ -145,7 +182,6 @@ func run() int {
 		return 1
 	} else {
 		commitRange = lastTag()
-		fmt.Println("git", "rev-list", commitRange+"..HEAD", "--merges", "--pretty=format:%B")
 		cmd = exec.Command("git", "rev-list", commitRange+"..HEAD", "--merges", "--pretty=format:%B") //nolint:gosec
 	}
 
@@ -184,7 +220,11 @@ func run() int {
 	for _, c := range commits {
 		body := trimTitle(c.body)
 		var key, prNumber, fork string
-		prefix, _ := getAreaLabel(c.merge)
+		prefix, err := getAreaLabel(c.merge)
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
 		switch {
 		case strings.HasPrefix(body, ":sparkles:"), strings.HasPrefix(body, "✨"):
 			key = features