diff --git a/Library/Homebrew/formula_cellar_checks.rb b/Library/Homebrew/formula_cellar_checks.rb
index da14f38e17..939b55b1cc 100644
--- a/Library/Homebrew/formula_cellar_checks.rb
+++ b/Library/Homebrew/formula_cellar_checks.rb
@@ -150,7 +150,6 @@ module FormulaCellarChecks
   private
 
   def relative_glob(dir, pattern)
-    return [] unless Pathname.new(dir).directory?
-    Dir.chdir(dir) { Dir[pattern] }
+    File.directory?(dir) ? Dir.chdir(dir) { Dir[pattern] } : []
   end
 end