Show the username as a fallback on feeds if full name is blank (#10438)

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lauris BH <lauris@nix.lv>

models/action.go

@@ -120,10 +120,13 @@ func (a *Action) ShortActUserName() string {
 	return base.EllipsisString(a.GetActUserName(), 20)
 }
 
-// GetDisplayName gets the action's display name based on DEFAULT_SHOW_FULL_NAME
+// GetDisplayName gets the action's display name based on DEFAULT_SHOW_FULL_NAME, or falls back to the username if it is blank.
 func (a *Action) GetDisplayName() string {
 	if setting.UI.DefaultShowFullName {
-		return a.GetActFullName()
+		trimmedFullName := strings.TrimSpace(a.GetActFullName())
+		if len(trimmedFullName) > 0 {
+			return trimmedFullName
+		}
 	}
 	return a.ShortActUserName()
 }

models/user.go

@@ -739,9 +739,11 @@ func (u *User) DisplayName() string {
 // GetDisplayName returns full name if it's not empty and DEFAULT_SHOW_FULL_NAME is set,
 // returns username otherwise.
 func (u *User) GetDisplayName() string {
-	trimmed := strings.TrimSpace(u.FullName)
+	if setting.UI.DefaultShowFullName {
-	if len(trimmed) > 0 && setting.UI.DefaultShowFullName {
+		trimmed := strings.TrimSpace(u.FullName)
-		return trimmed
+		if len(trimmed) > 0 {
+			return trimmed
+		}
 	}
 	return u.Name
 }