MethodHandles.publicLookup().in() returns Lookup with no permissions?

[Simone Bordet]

Hi,

testing the Jetty MethodHandle usages we encountered this situation:

.class org.openjdk.mh.Main
----
Class<?> klass = Main.class;
MethodHandles.Lookup lookup = MethodHandles.publicLookup().in(klass);
MethodHandle handle = lookup.findVirtual(klass, "test",
MethodType.methodType(String.class));
----

.module-info.java
----
module org.openjdk.mh {
    exports org.openjdk.mh to com.acme;
}
----

findVirtual() throws:
java.lang.IllegalAccessException: symbolic reference class is not
accessible: class org.openjdk.mh.Main, from
org.openjdk.mh.Main/noaccess (module org.openjdk.mh)

Removing the "to" clause from the exports in module-info.java fixes the issue.

Seems that a class cannot get a MethodHandle on itself, the reason
being that org.openjdk.mh is selectively exported in module-info.java.

Is this intended behavior?
I would have expected that a class could always get a MethodHandle on itself.
I tested this with 11, 15, and 16+25, all fail.

I have a simple reproducer, and I can open an OpenJDK bug.

Thanks!

-- 
Simone Bordet
---
Finally, no matter how good the architecture and design are,
to deliver bug-free software with optimal performance and reliability,
the implementation technique must be flawless.   Victoria Livschitz