A student of mine send me a code that can be reduced to this code
---
import java.lang.invoke.MethodHandles;
import java.lang.invoke.VarHandle;
public class ThereIsABugButWhere {
private static final VarHandle TEXT;
static {
try {
TEXT = MethodHandles.lookup().findVarHandle(ThereIsABugButWhere.class,
"text", String.class);
} catch (NoSuchFieldException | IllegalAccessException e) {
throw new AssertionError(e);
}
}
private final String text;
ThereIsABugButWhere() {
text = "FOO";
}
public void update(String s) {
TEXT.compareAndSet(this, "FOO", s);
}
public static void main(String[] args) {
new ThereIsABugButWhere().update("BAR");
}
}
---
If you execute it, you get
Exception in thread "main" java.lang.UnsupportedOperationException
at java.base/java.lang.invoke.VarForm.getMemberName(VarForm.java:99)
at
java.base/java.lang.invoke.VarHandleGuards.guard_LLL_Z(VarHandleGuards.java:77)
at ThereIsABugButWhere.update(ThereIsABugButWhere.java:22)
at ThereIsABugButWhere.main(ThereIsABugButWhere.java:26)
It takes me 20 mins to find the issue ...
I think we can improve the error message or even better report the issue at the
right location :)
regards,
Rémi
