Can't find library python

[Lele Gaifax]

I'm trying out current python-mode 6.0.4, taken from launchpad.

My emacs setup, loosely based on an old version of emacs-starter-kit, started to fail with the strange error I gave in the summary above. Even more strange, on a different machine, starting Emacs does not raise the error, but rather "automatically" opens a buffer loading the "python.el.gz" file coming with standard Emacs (24.0.91 from PPA, btw).

Upon further investigation, I isolated the problem to the latest version of python-mode, that does not occur with the official 6.0.3 released version.

To confirm that, I cloned the current launchpad branch in a temporary location, say "/tmp/python-mode-trunk", started Emacs with "emacs -Q" and executed the following in the *scratch* buffer:

(add-to-list 'load-path "/tmp/python-mode-trunk")
("/tmp/python-mode-trunk" "/etc/emacs-snapshot" "/etc/emacs" "/usr/local/share/emacs/24.0.91/site-lisp" "/usr/local/share/emacs/site-lisp" "/usr/share/emacs/24.0.91/site-lisp" "/usr/share/emacs/site-lisp" "/usr/share/emacs/24.0.91/lisp" "/usr/share/emacs/24.0.91/lisp/vc" "/usr/share/emacs/24.0.91/lisp/url" "/usr/share/emacs/24.0.91/lisp/textmodes" "/usr/share/emacs/24.0.91/lisp/progmodes" ...)
(load-library "python-mode")

At this point Emacs yielded the following traceback:

Debugger entered--Lisp error: (error "Can't find library python")
  signal(error ("Can't find library python"))
  error("Can't find library %s" "python")
  find-library-name("python")
  find-function-search-for-symbol(python-mode nil "python")
  find-function-noselect(python-mode)
  (car (find-function-noselect (quote python-mode)))
  (buffer-file-name (car (find-function-noselect (quote python-mode))))
  (file-name-directory (buffer-file-name (car (find-function-noselect (quote python-mode)))))
  (setq py-install-directory (file-name-directory (buffer-file-name (car (find-function-noselect (quote python-mode))))))
  (cond (py-install-directory (add-to-list (quote load-path) (expand-file-name py-install-directory)) (add-to-list (quote load-path) (concat (expand-file-name py-install-directory) "/completion")) (add-to-list (quote load-path) (concat py-install-directory "/pymacs")) (add-to-list (quote load-path) (concat (expand-file-name py-install-directory) "/test")) (add-to-list (quote load-path) (concat (expand-file-name py-install-directory) "/tools"))) (t (setq py-install-directory (file-name-directory (buffer-file-name (car (find-function-noselect (quote python-mode))))))))
  py-set-load-path()
  eval-buffer(#<buffer *load*> nil "/tmp/python-mode-trunk/python-mode.el" nil t) ; Reading at buffer position 25576
  load-with-code-conversion("/tmp/python-mode-trunk/python-mode.el" "/tmp/python-mode-trunk/python-mode.el" nil nil)
  load("python-mode")
  load-library("python-mode")
  eval((load-library "python-mode") nil)
  eval-last-sexp-1(t)
  eval-last-sexp(t)
  eval-print-last-sexp()
  call-interactively(eval-print-last-sexp nil nil)

Examining the source code, I see that the function py-set-load-path uses the variable py-install-directory... and effectively if I set the variable *before* loading the module, everything works as expected.

So, am I doing something wrong, or does the INSTALL instructions need a tweak mentioning the py-install-directory?

Thanks in advance, lele.

[Andreas Roehler (a-roehler)]

Hi,

your rationale reads plausible. Also think seeing the reason:

(py-set-load-path) looks for a function python-mode, resp. it's buffer-file at a moment,
were it isn't defined yet.

However can't reproduce the bug.

When starting from Emacs -Q
(add-to-list 'load-path "MY_PATH_to_Python-mode.el")
and
(load-library "python-mode")

seeing

Loading python-mode...done
t

;;;;;;;;;;

Anyway, will follow your proposal,

thanks,

Andreas

[Andreas Roehler (a-roehler)]

error you experience might be caused due load-library being designed for interactive use.

its written:

   (list (completing-read "Load library: "
     (apply-partially 'locate-file-completion-table
                                           load-path
                                           (get-load-suffixes)))))

think apply-partially might have done some unexpected things from your environment

while python-mode developed here provides 'python-mode, load fails looking for 'python

[Lele Gaifax (lelegaifax)]

Hi Andreas, thank you for investigating!

Regarding you #1 comment, did you check the buffers list? As said, on a different machine I end up having a buffer "python.elc" loaded into Emacs, without errors...

[Andreas Roehler (a-roehler)]

Am 28.11.2011 10:20, schrieb Lele Gaifax:
> Hi Andreas, thank you for investigating!
>
> Regarding you #1 comment, did you check the buffers list?

Hi Lele,

don't see the buffers list mentioned, don't think it's related.

BTW as the error reported presumably is caused by the starter-kit stuff,
a Python Emacs Environment with python-mode.el and other python-mode is
nascending here:

https://github.com/pdee/pdee

it's still within first steps, but also relates to starter-kit

python-mode.el developed here is mirrored

https://github.com/pdee/pdee/tree/master/python-modes/python-mode-el

  As said, on a
> different machine I end up having a buffer "python.elc" loaded into
> Emacs, without errors...
>

well, that's the python-mode shipped with GNU Emacs probably.

Regards,

Andreas

[Lele Gaifax (lelegaifax)]

> don't see the buffers list mentioned, don't think it's related.

I mention that case in the second paragraph of the original report:
upon loading the python-mode.el, Emacs ended up with three active
buffers, "*scratch*", "*Messages*" and "python.el"

> BTW as the error reported presumably is caused by the starter-kit
> stuff

I don't think that's possible: being paranoid, I tried with "emacs -Q"
*after* a "mv ~/.emacs.d ~/.emacs.d-out-of-the-way"...

> a Python Emacs Environment with python-mode.el and other
> python-mode is nascending here:
>
> https://github.com/pdee/pdee

Yes, thank you, I kept an eye on that. To be exact, my "loosely
esk-based startup" is actually

  https://github.com/gabrielelanaro/emacs-starter-kit

which seems in some way originated the pdee project.

Thanks again for the quick fix,
ciao, lele.