Question

I’m doing some not-so standard import of python modules. I’m adding a finder object to sys.meta_path to do things like importing a module via http/ssh/svn/etc. I’m able to successfully import the module using code like:

def load_module(self, fullname, some_path=None):
    """
    fullname is something like:    this.is.a.module
    """

    is_package = figure_out_if_this_is_a_package(fullname)
    file_contents = get_file_contents(fullname) # via http/ssh/svn, whatever

    mod = sys.modules.setdefault(fullname, imp.new_module(fullname))
    mod.__file__ = "<MyFancyMagicImporter>"
    mod.__loader__ = self

    if is_package:
        mod.__path__ = []
        mod.__package__ = fullname
    else:
        mod.__package__ = fullname.rpartition(".")[0]

    exec(file_contents, mod.__dict__)

    return mod

the problem occurs when the dynamically imported module (let’s call it ssh.test_module) tries to import something. If the ssh.test_module does something like import os, it actually ends up trying to do a relative import like import ssh.test_module.os. If this relative looking import fails, the import fails completely.

Help?

Update: BTW, I’m using python 2.7

UPDATE Here’s a better example that demonstrates the problem I’m having:

#!/usr/bin/env python

import sys
import imp

class Loader(object):
    def load_module(self, fullname, some_path=None):
        file_contents = ""
        if fullname == "loader_testing":
            file_contents = "import os"
        elif fullname == "loader_testing.blah":
            file_contents = "import sys\nimport os\nimport loader_testing.halb"
        elif fullname == "loader_testing.halb":
            file_contents = "print('HALBHALBHALB')"

        mod = sys.modules.setdefault(fullname, imp.new_module(fullname))
        mod.__file__ = "<%s>" % self.__class__.__name__
        mod.__loader__ = self

        is_package = fullname.count(".") == 0

        if is_package:
            mod.__path__ = []
            mod.__package__ = fullname
        else:
            mod.__package__ = fullname.rpartition('.')[0]
            mod.__path__ = []

        exec(file_contents, mod.__dict__)

        return mod

    def find_module(self, fullname, path=None):
        if fullname.find("loader_testing") == 0:
            print "loader_testing, fullname: %s" % fullname
            return self

        return None

sys.meta_path.append(Loader())

import loader_testing.blah

I would expect the above code to output something like:

loader_testing, fullname: loader_testing
loader_testing, fullname: loader_testing.blah
loader_testing, fullname: loader_testing.halb
HALBHALBHALB

Instead, you get this:

loader_testing, fullname: loader_testing
loader_testing, fullname: loader_testing.os
loader_testing, fullname: loader_testing.blah
loader_testing, fullname: loader_testing.sys
loader_testing, fullname: loader_testing.loader_testing
loader_testing, fullname: loader_testing.loader_testing.halb

Notice what seems like relative importing with the loader_testing.loader_testing.halb and such

Answer 1

What ended up fixing this was importing absolute_path from future. I thought that was already active by default in python 2.7.3, but I guess I was mistaken:

from __future__ import absolute_path