From 3bae6bfac34229064e5b539e7aa0b82dd14d9a8d Mon Sep 17 00:00:00 2001
From: Marius Balteanu <marius.balteanu@zitec.com>
Date: Tue, 10 Aug 2021 19:35:53 +0000
Subject: [PATCH] Fixed create duplicate follow relation fails with 500
 internal error (#35655).

git-svn-id: http://svn.redmine.org/redmine/trunk@21150 e93f8b46-1217-0410-a6f0-8f06a7374b81
---
 app/controllers/issue_relations_controller.rb |  9 ++++---
 .../issue_relations_controller_test.rb        | 25 +++++++++++++++++++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/app/controllers/issue_relations_controller.rb b/app/controllers/issue_relations_controller.rb
index 52be512f1..8143f4f4a 100644
--- a/app/controllers/issue_relations_controller.rb
+++ b/app/controllers/issue_relations_controller.rb
@@ -56,10 +56,13 @@ class IssueRelationsController < ApplicationController
       @relation.safe_attributes = params_relation
       @relation.init_journals(User.current)
 
-      unless saved = @relation.save
-        saved = false
-        unsaved_relations << @relation
+      begin
+        saved = @relation.save
+      rescue ActiveRecord::RecordNotUnique
+        @relation.errors.add :base, :taken
       end
+
+      unsaved_relations << @relation unless saved
     end
 
     respond_to do |format|
diff --git a/test/functional/issue_relations_controller_test.rb b/test/functional/issue_relations_controller_test.rb
index b5ea6cb93..099254979 100644
--- a/test/functional/issue_relations_controller_test.rb
+++ b/test/functional/issue_relations_controller_test.rb
@@ -216,6 +216,31 @@ class IssueRelationsControllerTest < Redmine::ControllerTest
     assert_include 'Related issue cannot be blank', response.body
   end
 
+  def test_create_duplicated_follows_relations_should_not_raise_exception
+    IssueRelation.create(
+      :issue_from => Issue.find(1), :issue_to => Issue.find(2),
+      :relation_type => IssueRelation::TYPE_PRECEDES
+    )
+
+    assert_no_difference 'IssueRelation.count' do
+      post(
+        :create,
+        :params => {
+          :issue_id => 2,
+          :relation => {
+            :issue_to_id => 1,
+            :relation_type => 'follows',
+            :delay => ''
+          }
+        },
+        :xhr => true
+      )
+    end
+
+    assert_response :success
+    assert_include 'has already been taken', response.body
+  end
+
   def test_bulk_create_with_multiple_issue_to_id_issues
     assert_difference 'IssueRelation.count', +3 do
       post :create, :params => {
-- 
2.39.5