Pylint gets confused: No name 'path' in module 'path'

[nedbat]

Pylint doesn't understand that path.py defines the name "path". It does so with the @alias decorator, which is only used once in the file. So there are six extra lines of code to define a decorator which only serves to confuse pylint.

Would you mind getting rid of the decorator and replacing it with path = Path? Then pylint will understand.

[sarina]

👍

[chrisidefix]

This latest fix (release 8.0) breaks compatibility with other packages using path.py (in particular pickleshare, which is used in ipython / jupyter). I had to revert to release 7.7.1 for now to get ipython working again.

It looks like pickleshare uses path.py like this: from path import path as Path and may need to be updated now, but I thought anyone else who has this problem might wanted to know.

Traceback (most recent call last):
  File "/usr/local/bin/ipython", line 7, in <module>
    from IPython import start_ipython
  File "/usr/local/lib/python2.7/site-packages/IPython/__init__.py", line 48, in <module>
    from .terminal.embed import embed
  File "/usr/local/lib/python2.7/site-packages/IPython/terminal/embed.py", line 16, in <module>
    from IPython.core.interactiveshell import DummyMod
  File "/usr/local/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 31, in <module>
    from pickleshare import PickleShareDB
  File "/usr/local/lib/python2.7/site-packages/pickleshare.py", line 41, in <module>
    from path import path as Path
ImportError: cannot import name path

[nedbat]

Wow, this isn't what I was hoping for at all. Why break the public interface of the package?

[ViktorHaag]

Well, it was broken around a major release boundary, so one could say at least this wasn't done with a 7.8.0 release. But still, I've had to revert back to 7.7.1 as well, as tools I need depend on the previous public interface.

[jaraco]

The intention has been to remove the deprecated path name since the 6.2 release, which was made almost a year ago, so this change was planned. The presence of the alias was to make the path name easily visible alongside the canonical Path declaration, rather than burying it near the end of the file.

The client libraries should be able to require path.py >= 6.2 and change their imports to reference the preferred name.

[whitmo]

is keeping path = Path really that big a deal? this change just broken a huge amount of code we are running here at canonical. 😿 🙍

[Nodd]

@whitmo 👍
"almost one year ago" isn't very far in the past for lots of codebases. Given that a simple path = Path keeps back compatibility, it seems logical to keep it. A big warning in the documentation would be useful too.

[jaraco]

Fair enough.

[chuckbutler]

@jaraco are we going to see a backwords compat release hit pypi? This is effecting by and large about 30 projects that I'm aware of here in the Juju ecosystem alone, I'm willing to bet it spins much larger when you start looking at other tools we're using.

[jaraco]

I've pulled 8.0 from PyPI

[chuckbutler]

Thanks! We'll start going through and pinning our dependencies so its far less of an impact when design decisions like this surface in the future. Thanks for the rapid response @jaraco

[codewarrior0]

IPython 4.0.0 (and previous) will do from path import * which doesn't work with 8.1 since path isn't in __all__. It also declares path.py as a requirement without pinning a version, so running pip install ipython on a clean install will give you a broken ipython

I'm going to pin 7.7.1 in my project now as a workaround.

[asampat3090]

@codewarrior0 could you specifically show how you did this? I tried to reinstall 7.7.1 for path.py but my Ipython 4.0.0 is still broken. Is there a specific version I should be using for pickleshare?

[codewarrior0]

I don't know about pickleshare. I must have been wrong about IPython 4.0.0, as it doesn't seem to be broken on a clean install - but IPython 3.2.1 certainly is.

[codewarrior0]

Here's what I did to get a broken IPython:

$ virtualenv ipytest
$ . ipytest/scripts/activate
$ pip install ipython==3.2.1
$ ipython
[...]
  File "ipytest\lib\site-packages\IPython\utils\text.py", line 28, in <module>
    from IPython.external.path import path
ImportError: cannot import name path

(IPython/external/path/__init__.py does from path import *)

And this is what it took to fix it:

$ pip install py.path==7.7.1
$ ipython
[...]
IPython 3.2.1 -- An enhanced Interactive Python.

In [1]:

[asampat3090]

Cool thanks! Worked for me. Definitely looking forward to a fix in IPython 4.0.0.