Homebrew snippet to use a git branch as a patch

git_patch_download.rb

class GitPatchDownloadStrategy < GitDownloadStrategy
  def initialize name, resource
    super
    @baseref = meta[:base]
  end
  def stage
    Homebrew.system("git", "-C", cached_location, "diff", @baseref, @ref) do
      $stdout.reopen('patch')
    end
  end
end
  
#patch :p1 do
#  url "https://github.com/foo/bar.git", :using => GitPatchDownloadStrategy, :base => "some-tag"
#end