[aspectj-users] VerifyError with inner classes

["FELBER Pascal" <pascal.felber@xxxxxxxx>]

Hi all,

I have encountered a problem with 'set' pointcuts and inner classes (not
sure whether this is a known limitation as I am new to this list).
Considering the code below, when I set a 'set' pointcut on the fields of
inner class Node, I get an error from the class verifier:

	Exception in thread "main" java.lang.VerifyError: (class:
test/List$Node, method: <init> signature: (Ltest/List;I)V) Expecting to
find object/array on stack

When I move the Node class out of the List class, it works fine. A quick
look at the decompiled code for the inner class (see below) shows that
the initial assignent of list$node.this$0, which happens before the call
to the constructor of the superclass, is intercepted while there is no
such assignment when I use an outer class. Is this the source of the
problem?

As a side question, what is the most efficient way to exclude from the
pointcut all accesses to instance fields made by the instance itself,
i.e., to exclude accesses of the form this.fieldName?

Thanks for your help,

Pascal

//////////////////////////////////////////////////////////////////////
// List.java
package test;

public class List {

	class Node {
		int value;
		Node next;

		Node(int v)
		{
			value = v;
		}
	}

	private Node head;

	public List()
	{
		head = null;
	}

	public void add(int v)
	{
		Node n = new Node(v);
		n.next = head;
		head = n;
	}

	public void print()
	{
		Node n = head;
		while (n != null) {
			System.out.print(" " + n.value);
			n = n.next;
		}
		System.out.println();
	}

	public static void main(String[] args) {
		List l = new List();
		for (int i = 0; i < 10; i++)
			l.add(i);
		l.print();
	}

}

//////////////////////////////////////////////////////////////////////
// ListAspect.aj
package test;

public aspect ListAspect {

	pointcut setField(Object t) : target(t) && set(* List.Node+.*);

	before(Object t) : setField(t) {
		System.out.println("WRITE");
		// Do something with t...
	}

}

//////////////////////////////////////////////////////////////////////
// List@xxxxxxxx
package test;


// Referenced classes of package test:
//            List, ListAspect

class List$Node
{

    int value;
    List$Node next;
    final List this$0;

    List$Node(int v)
    {
    //*   0    0:aload_0         
        List list1 = List.this;
    //    1    1:aload_1         
    //    2    2:astore_3        
        List$Node list$node = this;
    //    3    3:astore          4
 
ListAspect.aspectOf().ajc$before$test_ListAspect$1$3f3247a5(list$node);
    //    4    5:invokestatic    #37  <Method test.ListAspect
test.ListAspect.aspectOf()>
    //    5    8:aload           4
    //    6   10:invokevirtual   #41  <Method void
test.ListAspect.ajc$before$test_ListAspect$1$3f3247a5(java.lang.Object)>
        list$node.this$0 = list1;
    //    7   13:aload           4
    //    8   15:aload_3         
    //    9   16:putfield        #16  <Field test.List
test.List$Node.this$0>
        super();
    //   10   19:aload_0         
    //   11   20:invokespecial   #19  <Method void Object()>
    //*  12   23:aload_0         
        int i = v;
    //   13   24:iload_2         
    //   14   25:istore          5
        List$Node list$node1 = this;
    //   15   27:astore          6
 
ListAspect.aspectOf().ajc$before$test_ListAspect$1$3f3247a5(list$node1);
    //   16   29:invokestatic    #37  <Method test.ListAspect
test.ListAspect.aspectOf()>
    //   17   32:aload           6
    //   18   34:invokevirtual   #41  <Method void
test.ListAspect.ajc$before$test_ListAspect$1$3f3247a5(java.lang.Object)>
        list$node1.value = i;
    //   19   37:aload           6
    //   20   39:iload           5
    //   21   41:putfield        #21  <Field int test.List$Node.value>
    //   22   44:return          
    }
}