Currently we pass 2 arguments to the script render function: the template content, and the model. The purpose of this improvement is to add an optional 3rd argument, which is the template url. That may be very useful for some use cases (cache management on script side for example).
#19630 Support i18n and nested template loading in ScriptTemplateView render function
Important note: this is a seamless change for Nashorn users that can still invoke either render(template, model) or render(template, model, url), but Jython and JRuby are less permissive and make it mandatory to declare the 3 parameters.
As a consequence, Spring 4.2.0/4.2.1 Script templating users with Jython or JRuby should update their render function declaration from render(template, model) to render(template, model, url).