ArrayIndexOOB in o.a.c.c.serializers.util.Namespaces

[Andreas Hartmann]

Hi Cocoon developers,
I get the following exception when I use a certain logicsheet:
java.lang.ArrayIndexOutOfBoundsException: -3
at ...serializers.util.Namespaces.commit(Namespaces.java:158)
at 
...serializers.EncodingSerializer.startElement(EncodingSerializer.java:446)
at ...sax.XMLTeePipe.startElement(XMLTeePipe.java:83)

The problem occurs here (line marked with *):
    public String[][] commit() {
        int size = this.depth - this.last;
        String result[][] = new String[size][2];
        int k = 0;
        for (int x = this.last; x < this.depth; x++) {
*           result[k][NAMESPACE_PREFIX] = this.pre[x];

For debugging, I added some logging to the push() and pop() methods.
This is the result (the number at the end of the line is the current
Namespaces.last field):
[...]
        push [i18n] 4
          push [xsp] 4
            push [input] 4
              push [xspdoc] 4
                push [esql] 4
                  push [xsp-vvz-e] 4
                    push [tree] 4
                    pop  [tree] 3
                  pop  [xsp-vvz-e] 2
                pop  [esql] 1
              pop  [xspdoc] 0
            pop  [input] -1
          pop  [xsp] -2
        pop  [i18n] -3
      pop  [vvz] -4
[...]
Apparently this.last is increased on push, but not decreased on pop
which leads to a negative array index. Any ideas what goes wrong?
My logicsheet seems to be proper XSLT.
Thanks in advance,
-- Andreas