From d7455686332eb8b4b8aa40498f960da2cbb7ef89 Mon Sep 17 00:00:00 2001
From: Osama Sayegh <asooomaasoooma90@gmail.com>
Date: Thu, 24 Sep 2020 01:58:53 +0300
Subject: [PATCH] DEV: Stop polluting `Class` with deprecated settings methods
 (#10736)
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`self.class` here evaluates to `Class` and then we're calling `define_method` on it which means all classes will have those methods defined in them. For example:

```
~/discourse(master*) » rails c
Loading development environment (Rails 6.0.3.3)
[1] pry(main)> Integer.methods
=> [:sqrt,
 :yaml_tag,
 :email_domains_blacklist=,
 :email_domains_whitelist=,
 :unicode_username_character_whitelist=,
 :user_website_domains_whitelist=,
 :whitelisted_link_domains=,
 :email_domains_blacklist,
 :email_domains_whitelist,
 :unicode_username_character_whitelist,
...
...
```

Fix here is to use `self.define_singleton_method`.
---
 app/models/site_setting.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/app/models/site_setting.rb b/app/models/site_setting.rb
index daef5fa3c96..89a5e923fc3 100644
--- a/app/models/site_setting.rb
+++ b/app/models/site_setting.rb
@@ -242,11 +242,11 @@ class SiteSetting < ActiveRecord::Base
   }
 
   ALLOWLIST_DEPRECATED_SITE_SETTINGS.each_pair do |old_method, new_method|
-    self.class.define_method(old_method) do
+    self.define_singleton_method(old_method) do
       Discourse.deprecate("#{old_method.to_s} is deprecated, use the #{new_method.to_s}.", drop_from: "2.6")
       send(new_method)
     end
-    self.class.define_method("#{old_method}=") do |args|
+    self.define_singleton_method("#{old_method}=") do |args|
       Discourse.deprecate("#{old_method.to_s} is deprecated, use the #{new_method.to_s}.", drop_from: "2.6")
       send("#{new_method}=", args)
     end