Message12944

If I perform the module creation (on engine creation) unconditionally, I get a behaviour quite similar to Python script execution from the command-line and standard eval in the REPL:

>>> from javax.script import *
>>> engine = ScriptEngineManager().getEngineByName("python")
>>> c = SimpleScriptContext()
>>> engine.eval("print globals().keys()")
['__builtins__', '__doc__', '__name__', '__package__']
>>> engine.eval("print __name__")
__main__

So __name__ == "__main__" and a module with the engine's name space is added to sys.modules.

This does not otherwise interfere with the thread-bound globals/locals, so although I don't understand the use case for it, I feel this can't have broken it.

I *do* understand the use case for swapping the name space, when a Bindings object (or a ScriptContext) is given explicitly. These behave (as before) parallel with exec/eval when explicitly given a dictionary:

>>> engine.eval("print globals().keys()", c)
['__builtins__']
>>> engine.eval("print __name__", c)
__builtin__

The isolation of name spaces supports re-use of the engine, but there is no security value in it. With an explicit Bindings or ScriptContext, the namespace of the engine is reachable via sys.modules:

>>> engine.eval("import sys; print sys.modules['__main__'].__dict__.keys()", c)
['__builtins__', '__doc__', '__name__', '__package__']

Now in the code base at https://hg.python.org/jython/rev/58d45a33c32f .