diff --git a/Library/Homebrew/utils/git.rb b/Library/Homebrew/utils/git.rb
index 56727092dd78446b144a0e441fc8b5a9718cd849..4bb3eb2df57b793969c73f288516f49216bc5e4d 100644
--- a/Library/Homebrew/utils/git.rb
+++ b/Library/Homebrew/utils/git.rb
@@ -119,5 +119,10 @@ module Utils
       ENV["GIT_AUTHOR_EMAIL"] = Homebrew::EnvConfig.git_email if author
       ENV["GIT_COMMITTER_EMAIL"] = Homebrew::EnvConfig.git_email if committer
     end
+
+    def origin_branch(repo)
+      Utils.popen_read("git", "-C", repo, "symbolic-ref", "-q", "--short",
+                       "refs/remotes/origin/HEAD").chomp.presence
+    end
   end
 end