Fixes #7038: No error when hostgroup name exceeds 245 characters

app/models/hostgroup.rb

@@ -13,6 +13,7 @@ class Hostgroup < ActiveRecord::Base
   has_many :users, :through => :user_hostgroups
   validates :name, :format => { :with => /\A(\S+\s?)+\Z/, :message => N_("can't contain trailing white spaces.")}
   validates :root_pass, :allow_blank => true, :length => {:minimum => 8, :message => _('should be 8 characters or more')}
+  validate :title_and_lookup_key_length
   has_many :group_parameters, :dependent => :destroy, :foreign_key => :reference_id
   accepts_nested_attributes_for :group_parameters, :allow_destroy => true
   has_many_hosts
@@ -171,4 +172,11 @@ def used_taxonomy_ids(type)
     Host::Base.where(:hostgroup_id => self.path_ids).pluck(type).compact.uniq
   end
 
+  def title_and_lookup_key_length
+    max_length_for_name = self.send(:obj_type).length + 1
+    max_length_for_name += parent.title.length unless parent.nil?
+
+    errors.add(:name, _("Maximum for this name is #{255 - max_length_for_name} characters")) if 255 - (name.length + max_length_for_name) < 0
+  end
+
 end