Fix Idempotency-Key ignored when scheduling a post (#30084)

app/services/post_status_service.rb

@@ -160,7 +160,7 @@ class PostStatusService < BaseService
 
   def idempotency_duplicate
     if scheduled?
-      @account.schedule_statuses.find(@idempotency_duplicate)
+      @account.scheduled_statuses.find(@idempotency_duplicate)
     else
       @account.statuses.find(@idempotency_duplicate)
     end
@@ -211,7 +211,7 @@ class PostStatusService < BaseService
   end
 
   def scheduled_options
-    @options.tap do |options_hash|
+    @options.dup.tap do |options_hash|
       options_hash[:in_reply_to_id]  = options_hash.delete(:thread)&.id
       options_hash[:application_id]  = options_hash.delete(:application)&.id
       options_hash[:scheduled_at]    = nil

spec/services/post_status_service_spec.rb

@@ -54,6 +54,13 @@ RSpec.describe PostStatusService do
         .to not_change { account.statuses_count }
         .and(not_change { previous_status.replies_count })
     end
+
+    it 'returns existing status when used twice with idempotency key' do
+      account = Fabricate(:account)
+      status1 = subject.call(account, text: 'test', idempotency: 'meepmeep', scheduled_at: future)
+      status2 = subject.call(account, text: 'test', idempotency: 'meepmeep', scheduled_at: future)
+      expect(status2.id).to eq status1.id
+    end
   end
 
   it 'creates response to the original status of boost' do