Smarty registered classes check prevents use of class constants to avoid typo bugs in templates

My team makes extensive use of PHP class constants in our Smarty templates to avoid problems with typos in logic checks. With the new requirement that all classes be registered to access them statically our templates now generate deprecation warnings for each class constant.

It would be nice if class constants references (as opposed to static method calls) did not require class registration.

Alternatively I would like a supported way of overriding this behavior in a security policy. For example I would expect that overriding isTrustedStaticClass() or isTrustedStaticClassAccess() in my security policy would allow me to suppress the registered class requirement. However since the check for class registration is done outside the security policy this does not work unless the security policy also registers the class before returning. Calling Smarty::registerClass() from inside my security policy currently works but does not seem like it is a supported solution to the problem.

Start by tracing the registered-class check for static references and the security policy methods isTrustedStaticClass() and isTrustedStaticClassAccess(), which the issue names. Determine whether class constants can bypass registration or whether the policy can officially control it; done means the chosen behavior avoids unwanted deprecation warnings and has coverage for the affected template references.