Merged r17056 to 3.3-stable (#27663).

git-svn-id: http://svn.redmine.org/redmine/branches/3.3-stable@17058 e93f8b46-1217-0410-a6f0-8f06a7374b81

1 files changed, 9 insertions, 1 deletions

diff --git a/app/models/issue_relation.rb b/app/models/issue_relation.rb
index ee3a642a1..51d97f6a0 100644
--- a/app/models/issue_relation.rb
+++ b/app/models/issue_relation.rb
@@ -204,13 +204,19 @@ class IssueRelation < ActiveRecord::Base
 
   # Reverses the relation if needed so that it gets stored in the proper way
   # Should not be reversed before validation so that it can be displayed back
-  # as entered on new relation form
+  # as entered on new relation form.
+  #
+  # Orders relates relations by ID, so that uniqueness index in DB is triggered
+  # on concurrent access.
   def reverse_if_needed
     if TYPES.has_key?(relation_type) && TYPES[relation_type][:reverse]
       issue_tmp = issue_to
       self.issue_to = issue_from
       self.issue_from = issue_tmp
       self.relation_type = TYPES[relation_type][:reverse]
+
+    elsif relation_type == TYPE_RELATES && issue_from_id > issue_to_id
+      self.issue_to, self.issue_from = issue_from, issue_to
     end
   end
 
@@ -225,6 +231,8 @@ class IssueRelation < ActiveRecord::Base
       issue_from.blocks? issue_to
     when 'blocks'
       issue_to.blocks? issue_from
+    when 'relates'
+      self.class.where(issue_from_id: issue_to, issue_to_id: issue_from).present?
     else
       false
     end