Question

I create a file called foo_module.py containing the following code:

import shelve, whichdb, os

from foo_package.g import g

g.shelf = shelve.open("foo_path")
g.shelf.close() 

print whichdb.whichdb("foo_path")  # => dbhash
os.remove("foo_path")

Next to that file I create a directory called foo_package than contains an empty __init__.py file and a file called g.py that just contains:

class g:
    pass

Now when I run foo_module.py I get a weird error message:

Exception TypeError: "'NoneType' object is not callable" in ignored

But then, if I rename the directory from foo_package to foo, and change the import line in foo_module.py, I don’t get any error. Wtf is going on here?

Running Python 2.6.4 on WinXP.

Answer 1

I think you’ve hit a minor bug in 2.6.4’s code related to the cleanup at end of program. If you run python -v you can see exactly at what point of the cleanup the error comes:

# cleanup[1] foo_package.g
Exception TypeError: "'NoneType' object is not callable" in  ignored

Python sets references to None during the cleanup at the end of program, and it looks like it’s getting confused about the status of g.shelf. As a workaround you could set g.shelf = None after the close. I would also recommend opening a bug in Python’s bug tracker!