feat: support new username system

endpoints.go

@@ -53,6 +53,10 @@ var (
 		uDiscriminatorInt, _ := strconv.Atoi(uDiscriminator)
 		return EndpointCDN + "embed/avatars/" + strconv.Itoa(uDiscriminatorInt%5) + ".png"
 	}
+	EndpointDefaultUserAvatarMigrated = func(userID string) string {
+		userIDInt, _ := strconv.Atoi(userID)
+		return EndpointCDN + "embed/avatars/" + strconv.Itoa((userIDInt>>22)%5) + ".png"
+	}
 	EndpointUserBanner = func(uID, cID string) string {
 		return EndpointCDNBanners + uID + "/" + cID + ".png"
 	}

user.go

@@ -44,6 +44,10 @@ type User struct {
 	// The discriminator of the user (4 numbers after name).
 	Discriminator string `json:"discriminator"`
 
+	// The user's display name, if it is set.
+	// For bots, this is the application name.
+	GlobalName string `json:"global_name"`
+
 	// The token of the user. This is only present for
 	// the user represented by the current session.
 	Token string `json:"token"`
@@ -81,7 +85,14 @@ type User struct {
 }
 
 // String returns a unique identifier of the form username#discriminator
+// or username only if the discriminator is "0"
 func (u *User) String() string {
+	if u.isMigrated() {
+		return u.Username
+	}
+
+	// The code below handles applications and users without a migrated username.
+	// https://support-dev.discord.com/hc/en-us/articles/13667755828631
 	return u.Username + "#" + u.Discriminator
 }
 
@@ -94,9 +105,24 @@ func (u *User) Mention() string {
 //    size:    The size of the user's avatar as a power of two
 //             if size is an empty string, no size parameter will
 //             be added to the URL.
+//
+// Update: https://discord.com/developers/docs/change-log#default-avatars
+// Based on the update from new username
+// Users on the legacy username will use the discriminator % 5
+// Otherwise, users will use the (user_id >> 22) % 6
 func (u *User) AvatarURL(size string) string {
-	return avatarURL(u.Avatar, EndpointDefaultUserAvatar(u.Discriminator),
-		EndpointUserAvatar(u.ID, u.Avatar), EndpointUserAvatarAnimated(u.ID, u.Avatar), size)
+	defaultUserAvatar := EndpointDefaultUserAvatar(u.Discriminator)
+	if u.isMigrated() {
+		defaultUserAvatar = EndpointDefaultUserAvatarMigrated(u.ID)
+	}
+
+	return avatarURL(
+		u.Avatar,
+		defaultUserAvatar,
+		EndpointUserAvatar(u.ID, u.Avatar),
+		EndpointUserAvatarAnimated(u.ID, u.Avatar),
+		size,
+	)
 }
 
 // BannerURL returns the URL of the users's banner image.
@@ -105,3 +131,9 @@ func (u *User) AvatarURL(size string) string {
 func (u *User) BannerURL(size string) string {
 	return bannerURL(u.Banner, EndpointUserBanner(u.ID, u.Banner), EndpointUserBannerAnimated(u.ID, u.Banner), size)
 }
+
+// isMigrated returns true if the user is migrated from the legacy username system
+// https://discord.com/developers/docs/change-log#identifying-migrated-users
+func (u *User) isMigrated() bool {
+	return u.Discriminator == "" || u.Discriminator == "0"
+}

user_test.go

@@ -2,15 +2,43 @@ package discordgo
 
 import "testing"
 
-func TestUser(t *testing.T) {
+func TestUser_String(t *testing.T) {
 	t.Parallel()
 
-	user := &User{
-		Username:      "bob",
-		Discriminator: "8192",
+	tests := []struct {
+		name string
+		u    *User
+		want string
+	}{
+		{
+			name: "User with a discriminator",
+			u: &User{
+				Username:      "bob",
+				Discriminator: "8192",
+			},
+			want: "bob#8192",
+		},
+		{
+			name: "User without a discriminator",
+			u: &User{
+				Username: "aldiwildan",
+			},
+			want: "aldiwildan",
+		},
+		{
+			name: "User with discriminator set to 0",
+			u: &User{
+				Username:      "aldiwildan",
+				Discriminator: "0",
+			},
+			want: "aldiwildan",
+		},
 	}
-
-	if user.String() != "bob#8192" {
-		t.Errorf("user.String() == %v", user.String())
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := tc.u.String(); got != tc.want {
+				t.Errorf("User.String() = %v, want %v", got, tc.want)
+			}
+		})
 	}
 }