nightmare with relative imports, how does pep 366 work?

Posted by pygabriel on Stack Overflow See other posts from Stack Overflow or by pygabriel
Published on 2010-05-31T13:34:51Z Indexed on 2010/05/31 13:43 UTC
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I have a "canonical file structure" like that (I'm giving sensible names to ease the reading):

mainpack/

  __main__.py
  __init__.py 

  - helpers/
     __init__.py
     path.py

  - network/
     __init__.py
     clientlib.py
     server.py

  - gui/
     __init__.py
     mainwindow.py
     controllers.py

In this structure, for example modules contained in each package may want to access the helpers utilities through relative imports in something like:

# network/clientlib.py
from ..helpers.path import create_dir

The program is runned "as a script" using the __main__.py file in this way:

python mainpack/

Trying to follow the PEP 366 I've put in __main__.py these lines:

___package___ = "mainpack"
from .network.clientlib import helloclient

But when running:

$ python mainpack 
Traceback (most recent call last):
  File "/usr/lib/python2.6/runpy.py", line 122, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/lib/python2.6/runpy.py", line 34, in _run_code
    exec code in run_globals
  File "path/mainpack/__main__.py", line 2, in <module>
    from .network.clientlib import helloclient
SystemError: Parent module 'mainpack' not loaded, cannot perform relative import

What's wrong? What is the correct way to handle and effectively use relative imports?

I've tried also to add the current directory to the PYTHONPATH, nothing changes.

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