Fixes NoMethodError: undefined method 'first' for nil:NilClass (#3036)

app/models/status.rb

@@ -124,7 +124,7 @@ class Status < ApplicationRecord
   def ancestors(account = nil)
     ids      = Rails.cache.fetch("ancestors:#{id}") { (Status.find_by_sql(['WITH RECURSIVE search_tree(id, in_reply_to_id, path) AS (SELECT id, in_reply_to_id, ARRAY[id] FROM statuses WHERE id = ? UNION ALL SELECT statuses.id, statuses.in_reply_to_id, path || statuses.id FROM search_tree JOIN statuses ON statuses.id = search_tree.in_reply_to_id WHERE NOT statuses.id = ANY(path)) SELECT id FROM search_tree ORDER BY path DESC', id]) - [self]).pluck(:id) }
     statuses = Status.where(id: ids).group_by(&:id)
-    results  = ids.map { |id| statuses[id].first }
+    results  = ids.map { |id| statuses[id]&.first }.compact
     results  = results.reject { |status| filter_from_context?(status, account) }
 
     results

spec/models/status_spec.rb

@@ -179,6 +179,19 @@ RSpec.describe Status, type: :model do
     end
   end
 
+  describe '#ancestors' do
+    it 'ignores deleted records' do
+      first_status = Fabricate(:status, account: bob)
+      second_status = Fabricate(:status, thread: first_status, account: alice)
+
+      # Create cache and delete cached record
+      second_status.ancestors
+      first_status.destroy
+
+      expect(second_status.ancestors).to eq([])
+    end
+  end
+
   describe '#filter_from_context?' do
     pending
   end