It happens once in a while, a path gets into a mail, but with this patch it should happen nevermore.
Looks for paths in non-production and raises if it finds one.
unless Rails.env.production?
class ActionMailer::Base
def render_message_with_path_protection(method_name, body)
body = render_message_without_path_protection(method_name, body)
if body =~ %r{((href|src)=['"]/.*)}
raise "Use absolute path in mail urls! #{$1}"
end
body
end
alias_method_chain :render_message, :path_protection
end
end