[client] Use punycode domains internally consequently (#3867)

management/domain/domain.go

@@ -30,7 +30,7 @@ func (d Domain) SafeString() string {
 }
 
 // PunycodeString returns the punycode representation of the Domain.
-// This should only be used if a punycode domain is expected but only a string is supported.
+// This should only be used if a punycode domain is expected but only a string is supported (e.g. an external library).
 func (d Domain) PunycodeString() string {
 	return string(d)
 }

management/domain/list.go

@@ -1,7 +1,7 @@
 package domain
 
 import (
-	"sort"
+	"slices"
 	"strings"
 )
 
@@ -41,6 +41,7 @@ func (d List) ToSafeStringList() []string {
 }
 
 // String converts List to a comma-separated string.
+// This is useful for displaying domain names in a user-friendly format.
 func (d List) String() (string, error) {
 	list, err := d.ToStringList()
 	if err != nil {
@@ -50,7 +51,8 @@ func (d List) String() (string, error) {
 }
 
 // SafeString converts List to a comma-separated non-punycode string.
-// If a domain cannot be converted, the original string is used.
+// This is useful for displaying domain names in a user-friendly format.
+// If a domain cannot be converted, the original (punycode) string is used.
 func (d List) SafeString() string {
 	str, err := d.String()
 	if err != nil {
@@ -64,28 +66,22 @@ func (d List) PunycodeString() string {
 	return strings.Join(d.ToPunycodeList(), ", ")
 }
 
+// Equal checks if two domain lists are equal without considering the order.
 func (d List) Equal(domains List) bool {
 	if len(d) != len(domains) {
 		return false
 	}
 
-	sort.Slice(d, func(i, j int) bool {
-		return d[i] < d[j]
-	})
+	d1 := slices.Clone(d)
+	d2 := slices.Clone(domains)
 
-	sort.Slice(domains, func(i, j int) bool {
-		return domains[i] < domains[j]
-	})
+	slices.Sort(d1)
+	slices.Sort(d2)
 
-	for i, domain := range d {
-		if domain != domains[i] {
-			return false
-		}
-	}
-	return true
+	return slices.Equal(d1, d2)
 }
 
-// FromStringList creates a DomainList from a slice of string.
+// FromStringList creates a List from a slice of strings.
 func FromStringList(s []string) (List, error) {
 	var dl List
 	for _, domain := range s {