Review Request: JDK-8157464: StackWalker.getCallerClass() is not

[Daniel Fuchs]

Hi Mandy,

This looks good to me.
But I wonder about these 5 lines - isn't this introducing a change
of behavior if the caller is an anonymous class?

  149       InstanceKlass* ik = method->method_holder();
  150       if (ik->is_anonymous()) {
  151         // use the host class as the caller class
  152         ik = ik->host_klass();
  153       }

What is the reason for returning the host class instead?

best regards,

-- daniel

On 13/09/16 19:24, Mandy Chung wrote:
> Webrev:
>  http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8157464/webrev.01
>
> This revises the proposal posted some time ago [1].
>
> StackWalker::getCallerClass is a convenient method to find the caller class. It will return the invoker of the MethodHandle and java.lang.reflect.Method for the method calling StackWalker::getCallerClass, as it’s currently specified.
>
> This issue is related to MethodHandle for @CallerSensitive method.  It behaves as if the caller is the lookup class and in the current implementation, the actual caller class is not the lookup class but a generated class.
>
> One intended usage of StackWalker::getCallerClass is to be called by library code acting as an agent that calls @CallerSensitive method on behalf of the true caller and typically it will call an appropriate method with the appropriate parameter (e.g. ResourceBundle.getBundle(String, ClassLoader).
>
> Given that StackWalker::getCallerClass is not expected to be used by any @CS method, this patch proposes to catch and throw an exception if StackWalker::getCallerClass is called by a @CS method.  This will allow time to revisit this when such need is identified.
>
> thanks
> Mandy
> [1] http://mail.openjdk.java.net/pipermail/core-libs-dev/2016-July/042345.html
>