Index: app/controllers/issues_controller.rb
===================================================================
--- app/controllers/issues_controller.rb	(revision 16111)
+++ app/controllers/issues_controller.rb	(working copy)
@@ -355,6 +355,9 @@
         if reassign_to.nil?
           flash.now[:error] = l(:error_issue_not_found_in_project)
           return
+        elsif @issues.include?(reassign_to)
+          flash.now[:error] = l(:error_reassigning_time_entries_to_deleting_issue)
+          return
         else
           TimeEntry.where(['issue_id IN (?)', @issues]).
             update_all("issue_id = #{reassign_to.id}")
Index: config/locales/en.yml
===================================================================
--- config/locales/en.yml	(revision 16111)
+++ config/locales/en.yml	(working copy)
@@ -218,6 +218,7 @@
   error_no_tracker_allowed_for_new_issue_in_project: "The project doesn't have any trackers for which you can create an issue"
   error_no_projects_with_tracker_allowed_for_new_issue: "There are no projects with trackers for which you can create an issue"
   error_move_of_child_not_possible: "Subtask %{child} could not be moved to the new project: %{errors}"
+  error_reassigning_time_entries_to_deleting_issue: "Cannot reassign reported hours to the issue about to be deleted."
 
   mail_subject_lost_password: "Your %{value} password"
   mail_body_lost_password: 'To change your password, click on the following link:'
Index: test/functional/issues_controller_test.rb
===================================================================
--- test/functional/issues_controller_test.rb	(revision 16111)
+++ test/functional/issues_controller_test.rb	(working copy)
@@ -4684,6 +4684,14 @@
       end
     end
     assert_response :success
+
+    assert_no_difference 'Issue.count' do
+      assert_no_difference 'TimeEntry.count' do
+        # try to reassign time to the issue about to be deleted
+        delete :destroy, :ids => [1, 3], :todo => 'reassign', :reassign_to_id => 3
+      end
+    end
+    assert_response :success
   end
 
   def test_destroy_issues_from_different_projects