diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 3a8f3d24a6..2447777ff3 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -76,6 +76,8 @@ class AbstractDownloadStrategy
   end
 
   def basename_without_params
+    return unless @url
+
     # Strip any ?thing=wad out of .c?thing=wad style extensions
     File.basename(@url)[/[^?]+/]
   end