Handle validation errors on reverse issue relations (#27695).

Patch by Holger Just.


git-svn-id: http://svn.redmine.org/redmine/trunk@17141 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/controllers/issue_relations_controller.rb

@@ -46,7 +46,13 @@ class IssueRelationsController < ApplicationController
     @relation.issue_from = @issue
     @relation.safe_attributes = params[:relation]
     @relation.init_journals(User.current)
-    saved = @relation.save
+
+    begin
+      saved = @relation.save
+    rescue ActiveRecord::RecordNotUnique
+      saved = false
+      @relation.errors.add :base, :taken
+    end
 
     respond_to do |format|
       format.html { redirect_to issue_path(@issue) }