Adds method @initials@ to @Principal@ and return @nil@ by default (#42623).

git-svn-id: https://svn.redmine.org/redmine/trunk@23888 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/helpers/avatars_helper.rb

@@ -44,7 +44,7 @@ module AvatarsHelper
       if user.respond_to?(:mail)
         email = user.mail
         options[:title] = user.name unless options[:title]
-        options[:initials] = user.initials if options[:default] == "initials"
+        options[:initials] = user.initials if options[:default] == "initials" && user.initials.present?
       elsif user.to_s =~ %r{<(.+?)>}
         email = $1
       end

app/models/principal.rb

@@ -130,6 +130,11 @@ class Principal < ApplicationRecord
     to_s
   end
 
+  # Returns nil by default, subclasses should implement this method
+  def initials(formatter = nil)
+    nil
+  end
+
   def mail=(*args)
     nil
   end

test/unit/principal_test.rb

@@ -166,4 +166,8 @@ class PrincipalTest < ActiveSupport::TestCase
     r = Principal.like('vi_ci')
     assert_include user, r
   end
+
+  def test_initials_should_return_nil
+    assert_nil Group.first.initials
+  end
 end