Spring social ProviderSignInController signupurl
===

I am trying to write a grails plugin using Spring social core plugin. I get the provider popup and after I enter user and password it is giving me 404. As I debugged the code, it is coming into SpringSocialProviderSignInController handleSignIn() method and it is not getting anything for signup url. In grails plugin this is the code snipet

    
    if (userIds.size() == 0) {
      if (log.isDebugEnabled()) {
        log.debug("No user found in the repository, creating a new one...")
      }
      ProviderSignInAttempt signInAttempt = new ProviderSignInAttempt(connection, connectionFactoryLocator, usersConnectionRepository)
      request.setAttribute(ProviderSignInAttempt.SESSION_ATTRIBUTE, signInAttempt, RequestAttributes.SCOPE_SESSION)
      //TODO: Document this setting
      result = request.session.ss_oauth_redirect_on_signIn_attempt ?: config.page.handleSignIn
    }


I see that even in the regular spring social web jar this has similar logic. Except in the web there is a default set on signupUrl. I tried giving the same value(/signup) in config.page.handleSignIn but it did not help.

    if (userIds.size() == 0) {
			ProviderSignInAttempt signInAttempt = new ProviderSignInAttempt(connection, connectionFactoryLocator, usersConnectionRepository);
			request.setAttribute(ProviderSignInAttempt.SESSION_ATTRIBUTE, signInAttempt, RequestAttributes.SCOPE_SESSION);
			return redirect(signUpUrl);
		}

In general, I am trying to understand what this signUpUrl does. I am not able to go further after this. Is it mandatory to give signUpUrl? My understanding was no.  

Have asked the same question in spring social forum, but is not getting any response there.  Trying my luck here.