diff --git a/Library/Homebrew/dev-cmd/bump-formula-pr.rb b/Library/Homebrew/dev-cmd/bump-formula-pr.rb
index 278f7914b7..dfd59f3a23 100644
--- a/Library/Homebrew/dev-cmd/bump-formula-pr.rb
+++ b/Library/Homebrew/dev-cmd/bump-formula-pr.rb
@@ -101,7 +101,7 @@ module Homebrew
         end
       end
     end
-    [formula.tap.full_name, "origin/master", "-"]
+    [formula.tap&.full_name, "origin/master", "-"]
   end
 
   def bump_formula_pr