Critical Description
Section 4.3.4 of the Java Virtual Machine Specification, 2nd Edition, places the following restriction on Java byte code:
«A valid instruction sequence must not have an uninitialized object on the operand stack or in a local variable during a backwards branch, or in a local variable in code protected by an exception handler or a finally clause. Otherwise, a devious piece of code might fool the verifier into thinking it had initialized a class instance when it had, in fact, initialized a class instance created in a previous pass through a loop.»
There are a number of places where XSLTC generates code that violates this requirement; a strict implementation of the verification process described by the JVM specification would detect the invalid byte code. Most popular JVMs do not seem to detect this problem - presumably because their verification is less stringent - but this is a problem that needs to be fixed.
See copy16.xsl for an example of the offending code sequence. The id function seems to be involved in all cases that pose a problem.