Question

When run from the command-line (emacs filename.py) flymake and pylint work perfectly together. Errors are highlighted properly. (Although I can’t tooltip hover to get error details because it’s text-mode.)

When run from the GUI (Carbon Emacs) Flymake returns immediately, and the first line in the file is highlighted with the error “in <module>“. The first line is shows the error even on a “Hello World” script.) I’d like to get it working properly in GUI mode so that I can navigate with the mouse (I know, I know) and use tooltips to get details on the pylint reported errors.

I installed pylint with “easy_install pylint“, and the pylint and epylint scripts are in “~/py/scripts“. I added that directory to my PATH in my .bashrc:

export PATH=$PATH:~/py/scripts

(My .profile is a symlink to my .bashrc.)

I realized that Emacs-GUI was not loading the path from my .bashrc, so I created a ~/.MacOSX/environment.plist file, setting the PATH variable with the full PATH I see in the terminal.

Now in Emacs-GUI “(getenv "PATH")” the output appears correct:

"/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin:/usr/X11/bin:/Users/schof/py/scripts:/usr/X11R6/bin"

Similarly, the output of “C-h v exec-path” appears correct:

("/usr/bin" "/bin" "/usr/sbin" "/sbin" "/usr/local/bin" "/usr/local/git/bin" "/usr/X11/bin" "/Users/schof/py/scripts" "/Applications/Emacs.app/Contents/MacOS/libexec" "/Applications/Emacs.app/Contents/MacOS/bin" "/usr/X11R6/bin")

That leaves me with no further ideas for how I should resolve this. I’m by no means an emacs guru, so it’s possible I’m missing something obvious here; feel free to ask for more details.

OS X 10.6.7; Carbon Emacs 22.3.1; pylint 0.23.0.

Flymake / Pylint code from .emacs:

  (when (load "flymake" t)
      (defun flymake-pylint-init ()
        (let* ((temp-file (flymake-init-create-temp-buffer-copy
                           'flymake-create-temp-inplace))
           (local-file (file-relative-name
                        temp-file
                        (file-name-directory buffer-file-name))))
          (list "epylint" (list local-file))))

      (add-to-list 'flymake-allowed-file-name-masks
               '("\\.py\\'" flymake-pylint-init)))


;; Auto-start flymake-mode when you go into python-mode
(add-hook 'python-mode-hook
          '(lambda ()
                   (setq python-indent 4)
                   (flymake-mode)))

Update 2011-04-05 in response to @sanityinc’s answer:

Verbosity level 3 output of flymake in *messages*: (This does not make the source of the problem obvious to me.)

starting syntax check as new-line has been seen
flymake is running: nil
file /Users/schof/pytest.py, init=flymake-pylint-init [3 times]
create-temp-inplace: file=/Users/schof/pytest.py temp=/Users/schof/pytest_flymake.py
saved buffer pytest.py in file /Users/schof/pytest_flymake.py
started process 3221, command=(epylint pytest_flymake.py), dir=/Users/schof/
received 704 byte(s) of output from process 3221
file /Users/schof/pytest.py, init=flymake-pylint-init
parsed 'Traceback (most recent call last):', no line-err-info
parse line: file-idx=2 line-idx=3 file=/Users/schof/py/scripts/epylint line=4 text=in <module>
get-real-file-name: file-name=/Users/schof/py/scripts/epylint real-name=~/py/scripts/epylint
parsed '  File "/Users/schof/py/scripts/epylint", line 4, in <module>', got line-err-info
parsed '    import pkg_resources', no line-err-info
parse line: file-idx=2 line-idx=3 file=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py line=2556 text=in <module>
get-real-file-name: file-name=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py real-name=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py
parsed '  File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py", line 2556, in <module>', got line-err-info
parsed '    working_set.require(__requires__)', no line-err-info
parse line: file-idx=2 line-idx=3 file=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py line=620 text=in require
get-real-file-name: file-name=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py real-name=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py
parsed '  File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py", line 620, in require', got line-err-info
parsed '    needed = self.resolve(parse_requirements(requirements))', no line-err-info
parse line: file-idx=2 line-idx=3 file=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py line=518 text=in resolve
get-real-file-name: file-name=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py real-name=/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py
parsed '  File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py", line 518, in resolve', got line-err-info
parsed '    raise DistributionNotFound(req)  # XXX put more info here', no line-err-info
parsed 'pkg_resources.DistributionNotFound: pylint==0.23.0', no line-err-info
file /Users/schof/pytest.py, init=flymake-pylint-init
process 3221 exited with code 1
cleaning up using flymake-simple-cleanup
deleted file /Users/schof/pytest_flymake.py
created an overlay at (1-18)
pytest.py: 4 error(s), 0 warning(s) in 0.47 second(s)

For comparison, here is the output from flymake verbosity 3 when run from emacs text mode. The “hello world” file passed all pylint tests.

starting syntax check as new-line has been seen                                                                         
flymake is running: nil                                                                                                 
file /Users/schof/pytest.py, init=flymake-pylint-init [3 times]                                                         
create-temp-inplace: file=/Users/schof/pytest.py temp=/Users/schof/pytest_flymake.py                                    
saved buffer pytest.py in file /Users/schof/pytest_flymake.py                                                           
started process 3395, command=(epylint pytest_flymake.py), dir=/Users/schof/                                            
file /Users/schof/pytest.py, init=flymake-pylint-init                                                                   
process 3395 exited with code 0                                                                                         
cleaning up using flymake-simple-cleanup                                                                                
deleted file /Users/schof/pytest_flymake.py                                                                             
pytest.py: 0 error(s), 0 warning(s) in 0.30 second(s) 

Answer 1

To more clearly see what’s going wrong, increase flymake’s log level, then look in *messages*:

(setq flymake-log-level 3)

Without that info, I wouldn’t speculate on the likely problem.

There’s a trick for avoiding the environment.plist approach, BTW; you can get Emacs to ask your regular shell for your preferred PATH:

(defun set-exec-path-from-shell-PATH ()
  (let ((path-from-shell (replace-regexp-in-string
                          "[ \t\n]*$"
                          ""
                          (shell-command-to-string "$SHELL --login -i -c 'echo $PATH'"))))
    (setenv "PATH" path-from-shell)
    (setq exec-path (split-string path-from-shell path-separator))))

(when (and window-system (eq system-type 'darwin))
  ;; When started from Emacs.app or similar, ensure $PATH
  ;; is the same the user would see in Terminal.app
  (set-exec-path-from-shell-PATH))

(That’s lifted from my Emacs config, which has a bunch of flymake code in it, including a config for python using pyflakes, so you might want to take a look.)

Update: Now that you’ve added the verbose output, I see that your ~/py/epylint program can’t find pkg_resources, which points to PYTHONPATH being wrong. So, using a variation on the above technique, try this:

(defun setenv-from-shell (varname)
  (setenv varname (replace-regexp-in-string
                   "[ \t\n]*$"
                   ""
                   (shell-command-to-string (concat "$SHELL --login -i -c 'echo $" varname "'")))))

(setenv-from-shell "PYTHONPATH")