Routeing error while doing email on push

In stable version 6.7.2, Ruby 1.9.3p194 and Rails 4.0.3 when Email on push service is switched on, sidekiq log produces following error:

"No route matches" ... missing required keys: [:id]

when calling

in app/mailers/emails/projects.rb line:29 @target_url = project_commit_url(@Project, @compare.commit)

workaround: @target_url = project_commit_url(@Project, id: @compare.commit.id)