Re: [PATCH 1/2] emacs: Refactor subprocess stderr propagation

[Tomi Ollila <tomi.ollila@iki.fi>]

On Thu, Aug 17 2017, Vladimir Panteleev wrote:

> Load subprocess error output to a string in the callers, and propagate
> the error messages as a string parameter instead of a path to file
> names.
>
> Required to be able to avoid using temporary files for subprocess
> error output.
>
> * notmuch-lib.el: Update notmuch-check-async-exit-status,
>   notmuch-check-exit-status: accept an err parameter instead of
>   err-file; shift the responsibility of loading error messages from
>   files up the call stack.


both changes Look Good To Me, and works on emacs 25.2

(changed notmuch-command to "git" and saw error buffer populated as
expected, then M-x debug-on-entry make-process to verify that make-process
is actually called)

Tomi



> ---
>  emacs/notmuch-lib.el | 47 ++++++++++++++++++++++++++---------------------
>  1 file changed, 26 insertions(+), 21 deletions(-)
>
> diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
> index 337b20ac..1f743eff 100644
> --- a/emacs/notmuch-lib.el
> +++ b/emacs/notmuch-lib.el
> @@ -768,23 +768,23 @@ signaled error.  This function does not return."
>    (error "%s" (concat msg (when extra
>  			    " (see *Notmuch errors* for more details)"))))
>  
> -(defun notmuch-check-async-exit-status (proc msg &optional command err-file)
> +(defun notmuch-check-async-exit-status (proc msg &optional command err)
>    "If PROC exited abnormally, pop up an error buffer and signal an error.
>  
>  This is a wrapper around `notmuch-check-exit-status' for
>  asynchronous process sentinels.  PROC and MSG must be the
> -arguments passed to the sentinel.  COMMAND and ERR-FILE, if
> -provided, are passed to `notmuch-check-exit-status'.  If COMMAND
> -is not provided, it is taken from `process-command'."
> +arguments passed to the sentinel.  COMMAND and ERR, if provided,
> +are passed to `notmuch-check-exit-status'.  If COMMAND is not
> +provided, it is taken from `process-command'."
>    (let ((exit-status
>  	 (case (process-status proc)
>  	   ((exit) (process-exit-status proc))
>  	   ((signal) msg))))
>      (when exit-status
>        (notmuch-check-exit-status exit-status (or command (process-command proc))
> -				 nil err-file))))
> +				 nil err))))
>  
> -(defun notmuch-check-exit-status (exit-status command &optional output err-file)
> +(defun notmuch-check-exit-status (exit-status command &optional output err)
>    "If EXIT-STATUS is non-zero, pop up an error buffer and signal an error.
>  
>  If EXIT-STATUS is non-zero, pop up a notmuch error buffer
> @@ -793,9 +793,9 @@ be a number indicating the exit status code of a process or a
>  string describing the signal that terminated the process (such as
>  returned by `call-process').  COMMAND must be a list giving the
>  command and its arguments.  OUTPUT, if provided, is a string
> -giving the output of command.  ERR-FILE, if provided, is the name
> -of a file containing the error output of command.  OUTPUT and the
> -contents of ERR-FILE will be included in the error message."
> +giving the output of command.  ERR, if provided, is the error
> +output of command.  OUTPUT and ERR will be included in the error
> +message."
>  
>    (cond
>     ((eq exit-status 0) t)
> @@ -808,12 +808,7 @@ You may need to restart Emacs or upgrade your notmuch Emacs package."))
>  Emacs requested a newer output format than supported by the notmuch CLI.
>  You may need to restart Emacs or upgrade your notmuch package."))
>     (t
> -    (let* ((err (when err-file
> -		  (with-temp-buffer
> -		    (insert-file-contents err-file)
> -		    (unless (eobp)
> -		      (buffer-string)))))
> -	   (command-string
> +    (let* ((command-string
>  	    (mapconcat (lambda (arg)
>  			 (shell-quote-argument
>  			  (cond ((stringp arg) arg)
> @@ -889,9 +884,13 @@ error."
>    (with-temp-buffer
>      (let ((err-file (make-temp-file "nmerr")))
>        (unwind-protect
> -	  (let ((status (notmuch-call-notmuch--helper (list t err-file) args)))
> +	  (let ((status (notmuch-call-notmuch--helper (list t err-file) args))
> +		(err (with-temp-buffer
> +		       (insert-file-contents err-file)
> +		       (unless (eobp)
> +			 (buffer-string)))))
>  	    (notmuch-check-exit-status status (cons notmuch-command args)
> -				       (buffer-string) err-file)
> +				       (buffer-string) err)
>  	    (goto-char (point-min))
>  	    (read (current-buffer)))
>  	(delete-file err-file)))))
> @@ -931,9 +930,14 @@ status."
>      proc))
>  
>  (defun notmuch-start-notmuch-sentinel (proc event)
> -  (let ((err-file (process-get proc 'err-file))
> -	(sub-sentinel (process-get proc 'sub-sentinel))
> -	(real-command (process-get proc 'real-command)))
> +  "Process sentinel function used by `notmuch-start-notmuch'."
> +  (let* ((err-file (process-get proc 'err-file))
> +	 (err (with-temp-buffer
> +		(insert-file-contents err-file)
> +		(unless (eobp)
> +		  (buffer-string))))
> +	 (sub-sentinel (process-get proc 'sub-sentinel))
> +	 (real-command (process-get proc 'real-command)))
>      (condition-case err
>  	(progn
>  	  ;; Invoke the sub-sentinel, if any
> @@ -945,12 +949,13 @@ status."
>  	  ;; and there's no point in telling the user that (but we
>  	  ;; still check for and report stderr output below).
>  	  (when (buffer-live-p (process-buffer proc))
> -	    (notmuch-check-async-exit-status proc event real-command err-file))
> +	    (notmuch-check-async-exit-status proc event real-command err))
>  	  ;; If that didn't signal an error, then any error output was
>  	  ;; really warning output.  Show warnings, if any.
>  	  (let ((warnings
>  		 (with-temp-buffer
>  		   (unless (= (second (insert-file-contents err-file)) 0)
> +		     (goto-char (point-min))
>  		     (end-of-line)
>  		     ;; Show first line; stuff remaining lines in the
>  		     ;; errors buffer.
> -- 
> 2.13.3
>
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