Message9161

Some user of ours is trying to run an existing script which uses __file__ and finding that the value is undefined.

I distilled it down to a test case which I have verified on 2.7b3:

    public static void main(String[] args) throws Exception {
        ScriptEngine engine = new ScriptEngineManager().getEngineByExtension("py");
        engine.put(ScriptEngine.FILENAME, "/tmp/some_script.py");
        System.out.println(engine.eval("__file__"));
    }

Instead of printing the filename of the script, you get an exception:

    javax.script.ScriptException: NameError: name '__file__' is not defined in /tmp/some_script.py at line number 1
        at org.python.jsr223.PyScriptEngine.scriptException(PyScriptEngine.java:202)
        at org.python.jsr223.PyScriptEngine.eval(PyScriptEngine.java:42)
        at org.python.jsr223.PyScriptEngine.eval(PyScriptEngine.java:31)
        at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:264)

As an ironic twist, the error message itself the filename, so clearly *someone* knows the filename.

For the sake of comparison, the test program for JRuby's equivalent constant prints out the filename:

    public void testJRuby() throws Exception
    {
        ScriptEngine engine = new ScriptEngineManager().getEngineByExtension("rb");
        engine.put(ScriptEngine.FILENAME, "/tmp/some_script.rb");
        System.out.println(engine.eval("__FILE__"));
    }