fixes #2550

app/models/tag_alias.rb

@@ -82,6 +82,9 @@ class TagAlias < ActiveRecord::Base
       raise errors.full_messages.join("; ")
     end
 
+    tries = 0
+
+    begin
       admin = CurrentUser.user || User.admins.first
       CurrentUser.scoped(admin, "127.0.0.1") do
         update_column(:status, "processing")
@@ -94,9 +97,17 @@ class TagAlias < ActiveRecord::Base
         update_column(:status, "active")
       end
     rescue Exception => e
+      if tries < 5
+        tries += 1
+        sleep 2 ** tries
+        retry
+      end
+
+      update_forum_topic_for_error(e)
       update_column(:status, "error: #{e}")
       NewRelic::Agent.notice_error(e, :custom_params => {:tag_alias_id => id, :antecedent_name => antecedent_name, :consequent_name => consequent_name})
     end
+  end
 
   def is_pending?
     status == "pending"
@@ -246,6 +257,14 @@ class TagAlias < ActiveRecord::Base
     end
   end
 
+  def update_forum_topic_for_error(e)
+    if forum_topic
+      forum_topic.posts.create(
+        :body => "The tag alias #{antecedent_name} -> #{consequent_name} failed during processing. Reason: #{e}"
+      )
+    end
+  end
+
   def update_forum_topic_for_reject
     if forum_topic
       forum_topic.posts.create(

app/models/tag_implication.rb

@@ -125,6 +125,9 @@ class TagImplication < ActiveRecord::Base
       raise errors.full_messages.join("; ")
     end
 
+    tries = 0
+
+    begin
       admin = CurrentUser.user || User.admins.first
       CurrentUser.scoped(admin, "127.0.0.1") do
         update_column(:status, "processing")
@@ -134,9 +137,17 @@ class TagImplication < ActiveRecord::Base
         update_forum_topic_for_approve if update_topic
       end
     rescue Exception => e
+      if tries < 5
+        tries += 1
+        sleep 2 ** tries
+        retry
+      end
+
+      update_forum_topic_for_error(e)
       update_column(:status, "error: #{e}")
       NewRelic::Agent.notice_error(e, :custom_params => {:tag_implication_id => id, :antecedent_name => antecedent_name, :consequent_name => consequent_name})
     end
+  end
 
   def absence_of_circular_relation
     # We don't want a -> b && b -> a chains
@@ -237,6 +248,14 @@ class TagImplication < ActiveRecord::Base
     end
   end
 
+  def update_forum_topic_for_error(e)
+    if forum_topic
+      forum_topic.posts.create(
+        :body => "The tag implication #{antecedent_name} -> #{consequent_name} failed during processing. Reason: #{e}"
+      )
+    end
+  end
+
   def reject!
     update_forum_topic_for_reject
     destroy