PyLint “Unable to import” error - how to set PYTHO

Question

I'm running PyLint from inside Wing IDE on Windows. I have a sub-directory (package) in my project and inside the package I import a module from the top level, ie.

__init__.py
myapp.py
one.py
subdir\
    __init__.py
    two.py

Inside two.py I have import one and this works fine at runtime, because the top-level directory (from which myapp.py is run) is in the Python path. However, when I run PyLint on two.py it gives me an error:

F0401: Unable to import 'one'

How do I fix this?

Answer 1

I had this same issue and fixed it by installing pylint in my virtualenv and then adding a .pylintrc file to my project directory with the following in the file:

[Master]
init-hook='sys.path = list(); sys.path.append("./Lib/site-packages/")'

Answer 2

1) sys.path is a list.

2) The problem is sometimes the sys.path is not your virtualenv.path and you want to use pylint in your virtualenv

3) So like said, use init-hook (pay attention in ' and " the parse of pylint is strict)

[Master]
init-hook='sys.path = ["/path/myapps/bin/", "/path/to/myapps/lib/python3.3/site-packages/", ... many paths here])'

or

[Master]
init-hook='sys.path = list(); sys.path.append("/path/to/foo")'

.. and

pylint --rcfile /path/to/pylintrc /path/to/module.py

Answer 3

I had to update the system PYTHONPATH variable to add my App Engine path. In my case I just had to edit my ~/.bashrc file and add the following line:

export PYTHONPATH=$PYTHONPATH:/path/to/google_appengine_folder

In fact, I tried setting the init-hook first but this did not resolve the issue consistently across my code base (not sure why). Once I added it to the system path (probably a good idea in general) my issues went away.

Answer 4

I had the same problem and since i could not find a answer I hope this can help anyone with a similar problem.

I use flymake with epylint. Basically what i did was add a dired-mode-hook that check if the dired directory is a python package directory. If it is I add it to the PYTHONPATH. In my case I consider a directory to be a python package if it contains a file named "setup.py".

;;;;;;;;;;;;;;;;;
;; PYTHON PATH ;;
;;;;;;;;;;;;;;;;;

(defun python-expand-path ()
  "Append a directory to the PYTHONPATH."
  (interactive
   (let ((string (read-directory-name 
          "Python package directory: " 
          nil 
          'my-history)))
     (setenv "PYTHONPATH" (concat (expand-file-name string)
                  (getenv ":PYTHONPATH"))))))

(defun pythonpath-dired-mode-hook ()
  (let ((setup_py (concat default-directory "setup.py"))
    (directory (expand-file-name default-directory)))
    ;;   (if (file-exists-p setup_py)
    (if (is-python-package-directory directory)
    (let ((pythonpath (concat (getenv "PYTHONPATH") ":" 
                  (expand-file-name directory))))
      (setenv "PYTHONPATH" pythonpath)
      (message (concat "PYTHONPATH=" (getenv "PYTHONPATH")))))))

(defun is-python-package-directory (directory)
  (let ((setup_py (concat directory "setup.py")))
    (file-exists-p setup_py)))

(add-hook 'dired-mode-hook 'pythonpath-dired-mode-hook)

Hope this helps.

Answer 5

if you using vscode,make sure your package directory is out of the _pychache__ directory.

Answer 6

The solution to alter path in init-hook is good, but I dislike the fact that I had to add absolute path there, as result I can not share this pylintrc file among the developers of the project. This solution using relative path to pylintrc file works better for me:

[MASTER]
init-hook="from pylint.config import find_pylintrc; import os, sys; sys.path.append(os.path.dirname(find_pylintrc()))"

Note that pylint.config.PYLINTRC also exists and has the same value as find_pylintrc().