fix(issues): use unified user display name pattern for more places (#39852)

* Fix #39761

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/issues/reaction.go

@@ -350,7 +350,7 @@ func (list ReactionList) GetFirstUsers() string {
 		if buffer.Len() > 0 {
 			buffer.WriteString(", ")
 		}
-		buffer.WriteString(reaction.User.Name)
+		buffer.WriteString(reaction.User.DisplayNameWithFullName())
 		if rem--; rem == 0 {
 			break
 		}

models/user/user.go

@@ -465,6 +465,7 @@ func (u *User) EmailTo() string {
 }
 
 // TODO: DefaultShowFullName causes messy logic, there are already too many methods to display a user's "display name", need to refactor them
+// Search this TODO to see more details
 // * user.Name / user.FullName: directly used in templates
 // * user.DisplayName(): always show FullName if it's not empty, otherwise show Name
 // * user.GetDisplayName(): show FullName if it's not empty and DefaultShowFullName is set, otherwise show Name
@@ -491,6 +492,14 @@ func (u *User) GetDisplayName() string {
 	return u.Name
 }
 
+// DisplayNameWithFullName returns the username, full name is included if it is not empty
+func (u *User) DisplayNameWithFullName() string {
+	if fullName := strings.TrimSpace(u.FullName); fullName != "" {
+		return fmt.Sprintf("%s (%s)", u.Name, fullName)
+	}
+	return u.Name
+}
+
 // ShortName ellipses username to length (still used by many templates), it calls GetDisplayName and respects DEFAULT_SHOW_FULL_NAME
 func (u *User) ShortName(length int) string {
 	return util.EllipsisDisplayString(u.GetDisplayName(), length)

models/user/user_test.go

@@ -295,18 +295,13 @@ func TestNewGitSig(t *testing.T) {
 }
 
 func TestDisplayName(t *testing.T) {
-	users := make([]*user_model.User, 0, 20)
-	err := db.GetEngine(t.Context()).Find(&users)
-	assert.NoError(t, err)
+	u := &user_model.User{Name: "name"}
+	assert.Equal(t, "name", u.DisplayName())
+	assert.Equal(t, "name", u.DisplayNameWithFullName())
 
-	for _, user := range users {
-		displayName := user.DisplayName()
-		assert.Equal(t, strings.TrimSpace(displayName), displayName)
-		if len(strings.TrimSpace(user.FullName)) == 0 {
-			assert.Equal(t, user.Name, displayName)
-		}
-		assert.NotEmpty(t, strings.TrimSpace(displayName))
-	}
+	u = &user_model.User{Name: "name", FullName: "Full Name"}
+	assert.Equal(t, "Full Name", u.DisplayName())
+	assert.Equal(t, "name (Full Name)", u.DisplayNameWithFullName())
 }
 
 func TestCreateUserEmailAlreadyUsed(t *testing.T) {