Create instance actor if it hasn't been properly seeded (#15693)

An uncommon but somewhat difficult to digagnose issue is dealing with
improperly-seeded databases. In such cases, instance-signed fetches will
fail with a ActiveRecord::RecordNotFound error, usually caught and handled
as generic 404, leading people to think the remote resource itself has not
been found, while it's the local instance actor that does not exist.

This commit changes the code so that failure to find the instance actor
automatically creates a new one, so that improperly-seeded databases do
not cause any issue.

2 files changed, 3 insertions, 1 deletions

diff --git a/app/controllers/instance_actors_controller.rb b/app/controllers/instance_actors_controller.rb
index 4b074ca19..b3b5476e2 100644
--- a/app/controllers/instance_actors_controller.rb
+++ b/app/controllers/instance_actors_controller.rb
@@ -13,7 +13,7 @@ class InstanceActorsController < ApplicationController
   private
 
   def set_account
-    @account = Account.find(-99)
+    @account = Account.representative
   end
 
   def restrict_fields_to
diff --git a/app/models/concerns/account_finder_concern.rb b/app/models/concerns/account_finder_concern.rb
index 04b2c981b..0dadddad1 100644
--- a/app/models/concerns/account_finder_concern.rb
+++ b/app/models/concerns/account_finder_concern.rb
@@ -14,6 +14,8 @@ module AccountFinderConcern
 
     def representative
       Account.find(-99)
+    rescue ActiveRecord::RecordNotFound
+      Account.create!(id: -99, actor_type: 'Application', locked: true, username: Rails.configuration.x.local_domain)
     end
 
     def find_local(username)