diff --git a/lib/linguist/generated.rb b/lib/linguist/generated.rb
index fce3ab4b..9699bff9 100644
--- a/lib/linguist/generated.rb
+++ b/lib/linguist/generated.rb
@@ -486,6 +486,7 @@ module Linguist
     # Returns true or false.
     def generated_yarn_lock?
       return false unless name.match(/yarn\.lock/)
+      return false unless lines.count > 0
       return lines[0].include?("# THIS IS AN AUTOGENERATED FILE")
     end
   end