Re: python-try-complete

[Julian Scheid <julians37@googlemail.com>]

> Did you have any thoughts about the second problem I described in the 
> same mail - python-try-complete locking up when used in a remote buffer? 
> To quote from my previous mail,
> 
>   Either python-try-complete should refrain from launching the process
>   remotely by looking at (file-remote-p default-directory), or the
>   scripts it launches need to be prepared (e.g. in terms of quoting) for
>   being run remotely via ssh.

I had a chance to narrow it down a bit more. Here is the stack trace I 
get when I quit while python-try-complete blocks:

Debugger entered--Lisp error: (quit)
   accept-process-output(#<process Python> 5)
   python-send-receive("import emacs; print '_emacs_out ()'")
   run-python(nil t)
   python-proc()
   python-send-string("emacs.complete(\"exitCode\",\"import os\\nimport 
logging\\nimport Queue\\nimport threading\\n\")")
   python-send-receive("emacs.complete(\"exitCode\",\"import os\\nimport 
logging\\nimport Queue\\nimport threading\\n\")")
   byte-code("..." [symbol python-imports read-from-string 
python-send-receive format "emacs.complete(%S,%s)"] 6)
   python-symbol-completions("exitCode")
   (and symbol (python-symbol-completions symbol))
   (setq he-expand-list (and symbol (python-symbol-completions symbol)))
   (let ((symbol ...)) (he-init-string (- ... ...) (point)) (if (not 
...) (push he-search-string he-tried-table)) (setq he-expand-list (and 
symbol ...)))
   (if old nil (let (...) (he-init-string ... ...) (if ... ...) (setq 
he-expand-list ...)))
   (unless old (let (...) (he-init-string ... ...) (if ... ...) (setq 
he-expand-list ...)))
   (progn (unless old (let ... ... ... ...)) (while (and he-expand-list 
...) (pop he-expand-list)) (if he-expand-list (progn ... t) (if old ...) 
nil))
   (if (derived-mode-p (quote python-mode)) (progn (unless old ...) 
(while ... ...) (if he-expand-list ... ... nil)))
   (when (derived-mode-p (quote python-mode)) (unless old (let ... ... 
... ...)) (while (and he-expand-list ...) (pop he-expand-list)) (if 
he-expand-list (progn ... t) (if old ...) nil))
   python-try-complete(nil)
   apply(python-try-complete nil)
   hippie-expand(nil)
   call-interactively(hippie-expand)

And in *Python* I have:

Python 2.3.4 (#1, Feb  2 2005, 12:11:53)
[GCC 3.4.2 20041017 (Red Hat 3.4.2-6.fc3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> Traceback (most recent call last):
   File "<stdin>", line 1, in ?
ImportError: No module named emacs
 >>>

Now the interesting thing with the second line of this output is that my 
Emacs is running on top of OS X; Linux is running on the box on which 
the Python file lives that I've opened using Tramp (that was visited 
when I ran hippie-expand.)

So apparently Python gets run remotely (by the magic of Tramp?) but the 
"emacs" package which I suspect python-mode uses for helping with 
completion isn't available on the remote host; thus the whole completion 
attempt fails, but instead of gracefully failing python-try-complete 
sits there indefinitely.

There seem to be two problems here:

1) Proper exception and/or exit code handling is missing which would 
allow the Python script to exit with an error without locking up Emacs.

2) Either the external Python process should be forced to run locally 
even if the file is remote; or python-try-complete should refrain from 
launching a Python process at all if the file is remote; or 
python-try-complete should be prepared for its external process to run 
remotely and set up its environment properly (by uploading the emacs 
module and setting PYTHONPATH accordingly.)

As I said earlier I don't use python-try-complete anymore but FWIW 
simply not running Python when file-remote-p looks to me to be the best 
option.

I'm using Emacs 22.1.2 and tramp 2.1.13.

Hope this helps,

Julian