Re: [PATCH] Make the Emacs Erlang mode TRAMP-aware when compiling

On 08/21/2013 10:35 PM, Tomas Abrahamsson wrote:
> In Emacs it is possible to remotely edit a file, by opening for
> example /ssh:somehost.com:/path/to/file.erl.  In Emacs, the feature
> that makes this possible, is called TRAMP.  When compiling such a file,
> by typing C-c C-k, an inferior Erlang shell is opened on the remote
> host, but the compilation expression that was evaluated in the remote
> Erlang shell was:
>
>     c("/ssh:somehost.com:/path/to/file", [...]).
>
> which resulted in a "no such file or directory" error.
> This commit changes the compilation expression into:
>
>     c("/path/to/file", [...]).
>
> for files opened remotely via TRAMP.  The file name is adjusted
> similarly when compiling .yrl and .xrl files.
>
> In a buffer opened remotely, the Elisp function buffer-file-name
> returns the full path with TRAMP syntax.  In this example it would
> be "/ssh:somehost.com:/path/to/file.erl".  A new function,
> erlang-local-buffer-file-name, has been introduced, which peels off
> the TRAMP syntax on remotely opened files, while for locally opened
> files, it just calls buffer-file-name.
> ---
>   lib/tools/emacs/erlang.el | 44 +++++++++++++++++++++++++++++++++++++-------
>   1 file changed, 37 insertions(+), 7 deletions(-)
>
> diff --git a/lib/tools/emacs/erlang.el b/lib/tools/emacs/erlang.el
> index b5da9e7..6589047 100644
> --- a/lib/tools/emacs/erlang.el
> +++ b/lib/tools/emacs/erlang.el
> @@ -5286,7 +5286,7 @@ There exists two workarounds for this bug:
>     (inferior-erlang-prepare-for-input)
>     (let* ((dir (inferior-erlang-compile-outdir))
>   ;;; (file (file-name-nondirectory (buffer-file-name)))
> -	 (noext (substring (buffer-file-name) 0 -4))
> +	 (noext (substring (erlang-local-buffer-file-name) 0 -4))
>   	 (opts (append (list (cons 'outdir dir))
>   		       (if current-prefix-arg
>   			   (list 'debug_info 'export_all))
> @@ -5324,7 +5324,7 @@ unless the optional NO-DISPLAY is non-nil."
>   (defun inferior-erlang-compile-outdir ()
>     "Return the directory to compile the current buffer into."
>     (let* ((buffer-dir (directory-file-name
> -		      (file-name-directory (buffer-file-name))))
> +		      (file-name-directory (erlang-local-buffer-file-name))))
>   	 (parent-dir (directory-file-name
>   		      (file-name-directory buffer-dir)))
>            (ebin-dir (concat (file-name-as-directory parent-dir) "ebin"))
> @@ -5342,11 +5342,11 @@ unless the optional NO-DISPLAY is non-nil."
>   	(res (inferior-erlang-compute-erl-compile-command module-name opts))
>   	ccfn-entry
>   	done)
> -    (if (not (null (buffer-file-name)))
> +    (if (not (null (erlang-local-buffer-file-name)))
>   	(while (and (not done) (not (null ccfn)))
>   	  (setq ccfn-entry (car ccfn))
>   	  (setq ccfn (cdr ccfn))
> -	  (if (string-match (car ccfn-entry) (buffer-file-name))
> +	  (if (string-match (car ccfn-entry) (erlang-local-buffer-file-name))
>   	      (let ((c-fn (cdr ccfn-entry)))
>   		(setq done t)
>   		(if (not (null c-fn))
> @@ -5378,7 +5378,7 @@ unless the optional NO-DISPLAY is non-nil."
>   	 tmpvar tmpvar tmpvar2)))))
>
>   (defun inferior-erlang-compute-leex-compile-command (module-name opts)
> -  (let ((file-name        (buffer-file-name))
> +  (let ((file-name        (erlang-local-buffer-file-name))
>   	(erl-compile-expr (inferior-erlang-remove-any-trailing-dot
>   			   (inferior-erlang-compute-erl-compile-command
>   			    module-name opts))))
> @@ -5397,7 +5397,7 @@ unless the optional NO-DISPLAY is non-nil."
>   	    erl-compile-expr)))
>
>   (defun inferior-erlang-compute-yecc-compile-command (module-name opts)
> -  (let ((file-name        (buffer-file-name))
> +  (let ((file-name        (erlang-local-buffer-file-name))
>   	(erl-compile-expr (inferior-erlang-remove-any-trailing-dot
>   			   (inferior-erlang-compute-erl-compile-command
>   			    module-name opts))))
> @@ -5448,6 +5448,36 @@ unless the optional NO-DISPLAY is non-nil."
>         (setq strs (cdr strs)))
>       result))
>
> +(defun erlang-local-buffer-file-name ()
> +  ;; When editing a file remotely via tramp,
> +  ;; the buffer's file name may be for example
> +  ;; "/ssh:host.example.com:/some/path/x.erl"
> +  ;;
> +  ;; If I try to compile such a file using C-c C-k, an
> +  ;; erlang shell on the remote host is automatically
> +  ;; started if needed, but for it to successfully compile
> +  ;; the file, the c(...)  command that is sent must contain
> +  ;; the file name "/some/path/x.erl" without the
> +  ;; tramp-prefix "/ssh:host.example.com:".
> +  (cond ((null (buffer-file-name))
> +	 nil)
> +	((erlang-tramp-remote-file-p)
> +	 (erlang-tramp-get-localname))
> +	(t
> +	 (buffer-file-name))))
> +
> +(defun erlang-tramp-remote-file-p ()
> +  (and (fboundp 'tramp-tramp-file-p)
> +       (tramp-tramp-file-p (buffer-file-name))))
> +
> +(defun erlang-tramp-get-localname ()
> +  (let ((tramp-info (tramp-dissect-file-name (buffer-file-name))))
> +    (if (fboundp 'tramp-file-name-localname)
> +	(tramp-file-name-localname tramp-info)
> +      ;; In old versions of tramp, it was `tramp-file-name-path'
> +      ;; instead of the newer `tramp-file-name-localname'
> +      (tramp-file-name-path tramp-info))))
> +
>   ;; `next-error' only accepts buffers with major mode `compilation-mode'
>   ;; or with the minor mode `compilation-minor-mode' activated.
>   ;; (To activate the minor mode is out of the question, since it will
> @@ -5482,7 +5512,7 @@ Capable of finding error messages in an inferior Erlang buffer."
>     "Make the inferior Erlang change directory.
>   The default is to go to the directory of the current buffer."
>     (interactive)
> -  (or dir (setq dir (file-name-directory (buffer-file-name))))
> +  (or dir (setq dir (file-name-directory (erlang-local-buffer-file-name))))
>     (or (inferior-erlang-running-p)
>         (error "No inferior Erlang is running"))
>     (inferior-erlang-display-buffer)
Hello Tomas,
Thanks for the patch. I've applied it and assigned it to be reviewed by 
responsible developers.


-- 

BR Fredrik Gustafsson
Erlang OTP Team

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