config: fix lists (#2124)

internal/config/flatten.go

@@ -19,72 +19,52 @@ package config
 
 import (
 	"fmt"
-	"strconv"
+	"strings"
 )
 
-// flatten flattens the nested struct.
-//
-// All keys will be joined by dot
-// e.g. {"a": {"b":"c"}} => {"a.b":"c"}
-// or {"a": {"b":[1,2]}} => {"a.b.0":1, "a.b.1": 2}.
-func flatten(data map[string]interface{}) map[string]string {
-	ret := make(map[string]string)
-
-	for k, v := range data {
-		switch typed := v.(type) {
-		case map[interface{}]interface{}:
-			for fk, fv := range flatten(convertMap(typed)) {
-				ret[fmt.Sprintf("%s.%s", k, fk)] = fv
-			}
-		case map[string]interface{}:
-			for fk, fv := range flatten(typed) {
-				ret[fmt.Sprintf("%s.%s", k, fk)] = fv
-			}
-		case []interface{}:
-			for fk, fv := range flattenSlice(typed) {
-				ret[fmt.Sprintf("%s.%s", k, fk)] = fv
-			}
-		default:
-			ret[k] = fmt.Sprint(typed)
-		}
-	}
-
-	return ret
-}
-
-func flattenSlice(data []interface{}) map[string]string {
-	ret := make(map[string]string)
-
-	for idx, v := range data {
-		switch typed := v.(type) {
-		case map[interface{}]interface{}:
-			for fk, fv := range flatten(convertMap(typed)) {
-				ret[fmt.Sprintf("%d,%s", idx, fk)] = fv
-			}
-		case map[string]interface{}:
-			for fk, fv := range flatten(typed) {
-				ret[fmt.Sprintf("%d,%s", idx, fk)] = fv
-			}
-		case []interface{}:
-			for fk, fv := range flattenSlice(typed) {
-				ret[fmt.Sprintf("%d,%s", idx, fk)] = fv
-			}
-		default:
-			ret[strconv.Itoa(idx)] = fmt.Sprint(typed)
-		}
-	}
-
-	return ret
-}
-
-func convertMap(originalMap map[interface{}]interface{}) map[string]interface{} {
-	convertedMap := map[string]interface{}{}
-
+// convertMap converts a map with any comparable key type to a map with string keys.
+func convertMap[K comparable, V any](originalMap map[K]V) map[string]V {
+	convertedMap := make(map[string]V, len(originalMap))
 	for key, value := range originalMap {
-		if keyString, ok := key.(string); ok {
+		if keyString, ok := any(key).(string); ok {
 			convertedMap[keyString] = value
 		}
 	}
 
 	return convertedMap
 }
+
+// flatten flattens a nested map, joining keys with dots.
+// e.g. {"a": {"b":"c"}} => {"a.b":"c"}
+func flatten(data map[string]any) map[string]string {
+	result := make(map[string]string)
+
+	flattenHelper("", data, result)
+
+	return result
+}
+
+func flattenHelper(prefix string, data map[string]any, result map[string]string) {
+	for k, v := range data {
+		fullKey := k
+		if prefix != "" {
+			fullKey = prefix + "." + k
+		}
+
+		switch val := v.(type) {
+		case map[any]any:
+			flattenHelper(fullKey, convertMap(val), result)
+		case map[string]any:
+			flattenHelper(fullKey, val, result)
+		case []any:
+			strSlice := make([]string, len(val))
+			for i, elem := range val {
+				strSlice[i] = fmt.Sprint(elem)
+			}
+
+			result[fullKey] = strings.Join(strSlice, ",")
+		default:
+			result[fullKey] = fmt.Sprint(val)
+		}
+	}
+}