diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 850e72ac79..8b8fcd7c5b 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -383,6 +383,7 @@ class GitDownloadStrategy < AbstractDownloadStrategy
         safe_system 'git', 'submodule', '--quiet', 'foreach', '--recursive', sub_cmd
       end
     end
+    ENV['GIT_DIR'] = cached_location+'.git'
   end
 end