[Jython-users] Bug in version 2.0 compiler!

[D-Man <ds...@ri...>]

Through a small piece of stupid code, I found a bug in the Jython 2.0
compiler.

In a function (in a class, in a module if it matters) I had the
following code :

    del some_var

Originally some_var existed (a temporary local), but though some
modifications some_var no longer existed.  Trying to run the app
yielded the following (partial) result :

./run.bash Main.py
Traceback (innermost last):
  File "Main.py", line 33, in ?
  File "SessionTests\__init__.py", line 25, in ?
java.lang.NullPointerException
        at org.python.compiler.CodeCompiler.Name(Compiled Code)
        at org.python.parser.SimpleNode.visit(Compiled Code)
        at org.python.compiler.CodeCompiler.del_stmt(CodeCompiler.java:470)
        at org.python.parser.SimpleNode.visit(Compiled Code)
        at org.python.compiler.CodeCompiler.suite(Compiled Code)
        at org.python.parser.SimpleNode.visit(Compiled Code)
        at org.python.compiler.CodeCompiler.parse(Compiled Code)
        
        ... (very long stack trace)

        at org.python.core.PyTableCode.call(Compiled Code)
        at org.python.core.Py.runCode(Py.java:1055)
        at org.python.core.__builtin__.execfile(__builtin__.java:288)
        at org.python.core.__builtin__.execfile(__builtin__.java:292)
        at org.python.util.PythonInterpreter.execfile(PythonInterpreter.java:155)
        at org.python.util.jython.main(jython.java:159)

java.lang.NullPointerException: java.lang.NullPointerException



Obviously the error was on my part (can't del a var that DNE), but the
compiler should give a more informative error message (;-)).  Maybe it
should wait and give a NameError during exection, since it is possible
that I created the name through exec() or something.  (I didn't use
any fancy dynamism in this case)


I just checked against CPython and found this:

>>> def foo( ):
...     del dne
...
>>> foo()
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "<stdin>", line 2, in foo
UnboundLocalError: Local variable 'dne' referenced before assignment
>>>


All of this is on a Win2k box.  Version 2.0 for both python
interpreters, jdk1.1.8 for the jvm.

If you want any more info just yell ;-).

-D