From f0a5936091adb753e7aa8b90621dbe11defca152 Mon Sep 17 00:00:00 2001
From: evazion <noizave@gmail.com>
Date: Tue, 8 Mar 2022 03:15:16 -0600
Subject: [PATCH] Fix #5035: Double flags being created in certain conditions.

Lock the post to prevent a race condition when validating that the user
hasn't already flagged the post.
---
 app/models/post_flag.rb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/app/models/post_flag.rb b/app/models/post_flag.rb
index b46acb631..977274c1d 100644
--- a/app/models/post_flag.rb
+++ b/app/models/post_flag.rb
@@ -8,6 +8,8 @@ class PostFlag < ApplicationRecord
 
   belongs_to :creator, class_name: "User"
   belongs_to :post
+
+  before_validation { post.lock! }
   validates :reason, presence: true, length: { in: 1..140 }
   validate :validate_creator_is_not_limited, on: :create
   validate :validate_post, on: :create