From 1f88ecf6d85347fdbd1114c5447947f690d0eaef Mon Sep 17 00:00:00 2001
From: David Taylor <david@taylorhq.com>
Date: Thu, 31 Oct 2019 15:16:26 +0000
Subject: [PATCH] FIX: Cache `Discourse.system_user` separately for each
 multisite tenant (#8276)

This was not causing any known issue, because the system user ID is always the same across all sites. However, we should cache this on a per-site basis to be safe.
---
 lib/discourse.rb                  | 4 +++-
 spec/components/discourse_spec.rb | 6 ++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/discourse.rb b/lib/discourse.rb
index b7b65762fb1..561a4e979fa 100644
--- a/lib/discourse.rb
+++ b/lib/discourse.rb
@@ -536,7 +536,9 @@ module Discourse
   SYSTEM_USER_ID ||= -1
 
   def self.system_user
-    @system_user ||= User.find_by(id: SYSTEM_USER_ID)
+    @system_users ||= {}
+    current_db = RailsMultisite::ConnectionManagement.current_db
+    @system_users[current_db] ||= User.find_by(id: SYSTEM_USER_ID)
   end
 
   def self.store
diff --git a/spec/components/discourse_spec.rb b/spec/components/discourse_spec.rb
index 76a832c6d08..70559a5038d 100644
--- a/spec/components/discourse_spec.rb
+++ b/spec/components/discourse_spec.rb
@@ -130,6 +130,12 @@ describe Discourse do
 
   end
 
+  context '#system_user' do
+    it 'returns the system user' do
+      expect(Discourse.system_user.id).to eq(-1)
+    end
+  end
+
   context "#store" do
 
     it "returns LocalStore by default" do