From: Eugen Rochko <eugen@zeonfederated.com>
Date: Thu, 26 May 2022 20:14:47 +0000 (+0200)
Subject: Fix concurrent unfollowing decrementing follower count more than once (#18527)
X-Git-Url: https://git.xn--scling-oua.cat.family/?a=commitdiff_plain;h=2850503c6f6cbcc45e8cbdd693d906a505ceef8b;p=mastodon.git

Fix concurrent unfollowing decrementing follower count more than once (#18527)
---

diff --git a/app/services/unfollow_service.rb b/app/services/unfollow_service.rb
index 151f3674f..d83a60e4e 100644
--- a/app/services/unfollow_service.rb
+++ b/app/services/unfollow_service.rb
@@ -2,6 +2,8 @@
 
 class UnfollowService < BaseService
   include Payloadable
+  include Redisable
+  include Lockable
 
   # Unfollow and notify the remote user
   # @param [Account] source_account Where to unfollow from
@@ -13,7 +15,9 @@ class UnfollowService < BaseService
     @target_account = target_account
     @options        = options
 
-    unfollow! || undo_follow_request!
+    with_lock("relationship:#{[source_account.id, target_account.id].sort.join(':')}") do
+      unfollow! || undo_follow_request!
+    end
   end
 
   private