imp.reload - NoneType object has no attribute 'name'

Question

The following code:

def _IMPORT_(path)
    path = abspath(path)
    namespace = path[len(getcwd())+1:].replace('/', '_').strip('\\/;,. ')
    print(path)
    print(namespace)
    loader = importlib.machinery.SourceFileLoader(namespace, path+'.py')
    handle = loader.load_module(namespace)
    print(handle)
    importlib.reload(handle)
    return handle

Produces:

/home/torxed/git/test/unitest/unix
unitest_unix
<module 'unitest_unix' from '/home/torxed/git/test/unitest/unix.py'>

Traceback (most recent call last):
  File "network.py", line 17, in <module>
    handle = sock()
  File "network.py", line 9, in __init__
    sock = _IMPORT_('./unix')
  File "/home/torxed/git/test/unitest/helpers.py", line 13, in _IMPORT_
    imp.reload(handle)
  File "/usr/lib/python3.4/imp.py", line 315, in reload
    return importlib.reload(module)
  File "/usr/lib/python3.4/importlib/__init__.py", line 149, in reload
    methods.exec(module)
  File "<frozen importlib._bootstrap>", line 1134, in exec
AttributeError: 'NoneType' object has no attribute 'name'

This works perfectly in Python 3.3.5 where this sort of operation was introduced (there were some similar import-mechanics before this). However on Python 3.4.2 This apparently doesn't work.

What's changed since 3.3.5? Can't find any traces of it or the change is somewhere in the middle of the releases. There were a patch last year for this exact behavior where the environment variables wasn't passed down but that appears to be working here.

Weirdly, in my Python 3.4.2 (Mac OS X) it also doesn't work but I get: `AttributeError: 'module' object has no attribute 'machinery'`. — Simeon Visser, Dec 03 '14 at 14:45

score 11 · Answer 1 · answered Mar 23 '15 at 18:40

I get the same error when I try to reload a file after switching folders.

For example:

Create a simple module:

In [10]: %%file temp.py
    ...: message = "Hello World!"
    ...: 
Writing temp.py

Load the module and print a message:

In [14]: import temp
    ...: print(temp.message)
Hello World!

Change the message:

In [17]: temp.message = 'Hello brave new world!'
    ...: print(temp.message)
Hello brave new world!

Reload the module to get back the original message:

In [18]: import imp
    ...: imp.reload(temp)
    ...: print(temp.message)
Hello World!

Everything good so far...

Now change paths:

In [20]: cd ..

Try to reload the module:

In [24]: imp.reload(temp)
Traceback (most recent call last):

  File "<ipython-input-24-7fa95de0f250>", line 1, in <module>
imp.reload(temp)

  File "/home/user/anaconda3/lib/python3.4/imp.py", line 315, in reload
return importlib.reload(module)

  File "/home/user/anaconda3/lib/python3.4/importlib/__init__.py", line 149, in reload
methods.exec(module)

  File "<frozen importlib._bootstrap>", line 1134, in exec

AttributeError: 'NoneType' object has no attribute 'name'

In my case, the solution was to switch back to the path where the imports were made originally.

Thank you so much! I had the same problem and could not find it. When I read your answer, I realised that my script does its import with a path changing context manager. I was not aware that reload does not save the import path! Now I have to use the same context manager that I used for importing, and all is fine. But it is really annoying, because the module still knows the path... — Christian Tismer, Sep 04 '17 at 12:36
I changed the directory using os.chdir, that was the issue for me, i changed back to the original directory and reload worked fine. — SEDaradji, Apr 04 '18 at 17:25

score 1 · Answer 2 · answered Jul 25 '19 at 14:33

Indeed importlib.reload seems to only work if you are in the correct directory. To get around this, I wrote a helper function that I can call:

def reload( module ):
  import os
  import os.path
  import importlib

  cwd = os.getcwd()
  os.chdir( os.path.dirname(os.path.abspath(module.__file__)) )
  importlib.reload( module )
  os.chdir( cwd )

imp.reload - NoneType object has no attribute 'name'

2 Answers2