Re: Why is TAB-completion in shell not working for some commands?

[Jonathan Oddie]

Hi all,

One more detail about this that surprised me: the last component
of `exec-path' is always ignored by tab-completion in shell-mode. I
thought this was weird initially, but it's because by default
the last component of `exec-path' will be a directory of executables
Emacs uses internally: stuff like `vcdiff' and `movemail'.

This also means one needs to be a bit careful about setting the value of
`exec-path'. I wonder if there should be a note about this in the
docstring either for `exec-path' or `shell-dynamic-complete-as-command'?

cheers,
Jonathan

On 9 Nov 2011, at 18:05, Jonathan Oddie wrote:

> Hi Marius,
> 
> I did a couple of experiments and I think the below works better than
> my previous code:
> 
> (let ((path (shell-command-to-string ". ~/.profile; echo -n $PATH")))
>  (setenv "PATH" path)
>  (setq exec-path 
>       (append
>        (split-string-and-unquote path ":")
>        exec-path)))
> 
> This makes sure to read your bash startup before echoing the PATH env
> variable; I hadn't thought of that before.
> 
> Also, I'm pretty sure now it really is `exec-path' that makes the
> difference, not the PATH environment variable itself.  Here's the
> docstring for `shell-dynamic-complete-command':
> 
>> This function is similar to `comint-dynamic-complete-filename', except that 
>> it
>> searches `exec-path' (minus the trailing Emacs library path) for completion
>> candidates.  Note that this may not be the same as the shell's idea of the
>> path.
> 
> So as long as `exec-path' gets set correctly it *ought* to work. Let
> me know if that helps, I think we must be close to the solution now!
> 
> cheers,
> Jonathan
> 
> 
> 
> On 9 Nov 2011, at 17:51, Marius Hofert wrote:
> 
>> 
>> On 2011-11-09, at 18:38 , Jonathan Oddie wrote:
>> 
>>> 
>>> Hi Marius,
>>> 
>>>> 1) If I start emacs from the terminal, TAB-completion works (as reported 
>>>> earlier). Now the emacs I start from the terminal is actally (output of 
>>>> "which emacs"):
>>>> /Applications/Emacs.app/Contents/MacOS//emacs
>>>> and not the /Applications/Emacs.app (the GUI version one clicks on in the 
>>>> dock). So when I started emacs from the terminal, I used Options -> Keep 
>>>> in Dock to keep that in the dock instead of /Applications/Emacs.app. 
>>>> Starting the former, I again did not have TAB-completion, so it only works 
>>>> when (really) starting emacs from the terminal (which is funny cause I 
>>>> thought I can get rid of the Mac's terminal since I have a shell in 
>>>> emacs...)
>>>> Don't know if that makes sense to the experts, I just wanted to report on 
>>>> this.
>>> 
>>> Those two are actually the same
>>> thing. /Applications/Emacs.app/Contents/MacOS/emacs is just the
>>> executable file hidden inside the Emacs.app bundle. So it really does
>>> depend on starting from the Terminal and picking up your PATH
>>> settings.
>> 
>> okay
>> 
>>> 
>>>> [snip]
>>> 
>>>> 
>>>> => Clearly, the /opt-directories are missing. I haven't tried but one 
>>>> might just add all directories from PATH to exec-path, but whenever I 
>>>> change PATH, I have to remember to do the same for exec-path. Is there a 
>>>> nicer way?
>>> 
>>> Yes, I'd try adding your /opt directories to `exec-path' first and see if 
>>> that fixes
>>> the problem. You can either something like the (setq exec-path (append ... 
>>> )) solution in my last email, or the following:
>>> 
>>> (add-to-list 'exec-path "/some/path/here")
>>> 
>>> Note that you might *also* need to set the environment PATH variable
>>> from within Emacs; that's the line with `mapconcat' in my prev
>>> email. As I said, I forget exactly how each of these things interacts
>>> with shell-mode's tab-completion.
>>> 
>>> If that works, the nicer solution would probably involve having your
>>> .emacs run a short shell script to print out and parse the value of
>>> PATH set in your .bashrc (or wherever), and set PATH and `exec-path'
>>> based on that. I'll try and work out a quick hack for this later this
>>> evening, if someone doesn't beat me to it ;-)
>>> 
>>> cheers,
>>> Jonathan
>> 
>> 
>> Okay, in the meantime, I tried something like:
>> (setq exec-path (getenv "PATH"))
>> but that of course failed.
>> 
>> I then put in:
>> (setq exec-path (append exec-path '("/opt/local/bin"))); set exec-path
>> (setenv "PATH" (mapconcat 'identity exec-path ":")); set PATH
>> and restarted emacs. Still no TAB-completion :-(
>> 
>> If that helps, I originally had the following to get the same PATH as in the 
>> terminal:
>> (setq explicit-bash-args (list "--login" "-i"))
>> (that with the seq exec-path command above also did not work, though)
>> 
>> I'll try what you suggested in your recent mail, soon.
>> 
>> 
>> 
>