Fix #3378 - If favourite/reblog already exists, return it instead of failing (#3641)

app/services/favourite_service.rb

@@ -10,6 +10,10 @@ class FavouriteService < BaseService
   def call(account, status)
     authorize_with account, status, :show?
 
+    favourite = Favourite.find_by(account: account, status: status)
+
+    return favourite unless favourite.nil?
+
     favourite = Favourite.create!(account: account, status: status)
 
     if status.local?

app/services/reblog_service.rb

@@ -13,6 +13,10 @@ class ReblogService < BaseService
 
     authorize_with account, reblogged_status, :reblog?
 
+    reblog = account.statuses.find_by(reblog: reblogged_status)
+
+    return reblog unless reblog.nil?
+
     reblog = account.statuses.create!(reblog: reblogged_status, text: '')
 
     DistributionWorker.perform_async(reblog.id)