Using marshal to manually "import" a python module

[David Hirschfield]

I had a situation recently that required I manually load python bytecode 
from a .pyc file on disk.

So, for the most part, I took code from imputil.py which loads the .pyc 
data via the marshal module and then exec's it into a newly created 
module object (created by imp.new_module()). The relevant pieces of code 
are in imputil.py_suffix_importer and imputil.Importer._process_result 
(where it exec's the code into the module's __dict__)

The strange thing is, it worked fine locally on my two machines (32bit 
running python 2.3.5 and 64bit running python 2.4.1), but when run by a 
64bit machine on the network, it would fail every time in the following 
manner:

My marshal/exec-based loader would load the module from the pyc 
apparently without problems, but if I then pulled a specific function 
attr out of the resulting module object, and that function called 
another function defined within the same module, it would raise a 
"TypeError: 'NoneType' object is not callable" exception when attempting 
to call that second function. So the setup is:

module blah:
    def A():
        ...

    def B():
        x = A()

compiled to bytecode: blah.pyc
then, in my program:

m = my_marshal_loader("blah.pyc")
f = getattr(m,"B")

x = f()

raises "TypeError: 'NoneType' object is not callable" inside that call 
to f(), on the line x = A(), as though A is a None and not the function 
object defined in the module.

I can't figure out why this would work locally, but not when the module 
is loaded across a network. In fact, I have no idea what would ever 
cause it not to see A as a function. I'm stumped, and this is over my 
head as far as intimate knowledge of the direct loading of python 
bytecode via marshal is concerned...so I'm not clear on the best way to 
debug it. If anyone has an inkling of what might be going on, I'd love 
to hear it.

Thanks in advance,
-Dave

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