ModuleNotFoundError: No module named 'packaging'

[johanndiedrick]

I started a fresh install of fastai2 and got the following error when installing with pip:

(fastai2) paperspace@ps4y32elp:~/fastai2$ pip install git+https://github.com/fastai/fastai2
Collecting git+https://github.com/fastai/fastai2
  Cloning https://github.com/fastai/fastai2 to /tmp/pip-req-build-osgksw0h
  Running command git clone -q https://github.com/fastai/fastai2 /tmp/pip-req-build-osgksw0h
    ERROR: Command errored out with exit status 1:
     command: /home/paperspace/anaconda3/envs/fastai2/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-req-build-osgksw0h/setup.py'"'"'; __file__='"'"'/tmp/pip-req-build-osgksw0h/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-req-build-osgksw0h/pip-egg-info
         cwd: /tmp/pip-req-build-osgksw0h/
    Complete output (5 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-req-build-osgksw0h/setup.py", line 1, in <module>
        from packaging.version import parse
    ModuleNotFoundError: No module named 'packaging'
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.

This was solved by running pip install packaging and re-rerunning the pip install command for fastai2, but I wasn't sure where upstream this fix could/should be made. Just wanted to let you all know.

[sgugger]

For a dev install, you need to pip install packaging before being able to run the setup. We can't work around by just putting as a dep since the setup file itself uses packaging.
Note that this is documented in the README.

[sgugger]

Oh actually you're right, it's only mentioned for the dev install, will fix that today!