From: Mark Walters <markwalters1009@gmail.com>
To: Austin Clements <amdragon@MIT.EDU>,notmuch@notmuchmail.org
Subject: Re: [PATCH 07/10] emacs: Use --use-schema for search
In-Reply-To: <20121213014341.GC6187@mit.edu>
References: <1354416002-3557-1-git-send-email-amdragon@mit.edu>
	<1354416002-3557-7-git-send-email-amdragon@mit.edu>
	<87ehj1gc9x.fsf@qmul.ac.uk> <20121213014341.GC6187@mit.edu>
User-Agent: Notmuch/0.14+155~g7edfdc3 (http://notmuchmail.org) Emacs/23.4.1
	(x86_64-pc-linux-gnu)
Date: Thu, 13 Dec 2012 11:00:32 +0000
Message-ID: <87wqwmdxnz.fsf@qmul.ac.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Precedence: list

On Thu, 13 Dec 2012, Austin Clements <amdragon@MIT.EDU> wrote:
> Quoth Mark Walters on Dec 08 at  8:48 am:
>> On Sun, 02 Dec 2012, Austin Clements <amdragon@MIT.EDU> wrote:
>> > We detect the special exit statuses and use these to produce specific
>> > diagnostic messages.
>> > ---
>> >  emacs/notmuch-lib.el |   32 ++++++++++++++++++++++++++++++++
>> >  emacs/notmuch.el     |   17 +++++++++++++----
>> >  2 files changed, 45 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
>> > index 9402456..49b0da6 100644
>> > --- a/emacs/notmuch-lib.el
>> > +++ b/emacs/notmuch-lib.el
>> > @@ -325,6 +325,38 @@ string), a property list of face attributes, or a list of these."
>> >  	(put-text-property pos next 'face (cons face cur))
>> >  	(setq pos next)))))
>> >  
>> > +(defun notmuch-pop-up-error (msg)
>> > +  "Pop up an error buffer displaying MSG."
>> > +
>> > +  (let ((buf (get-buffer-create "*Notmuch errors*")))
>> > +    (with-current-buffer buf
>> > +      (view-mode)
>> > +      (let ((inhibit-read-only t))
>> > +	(erase-buffer)
>> > +	(insert msg)
>> > +	(unless (bolp)
>> > +	  (insert "\n"))
>> > +	(goto-char (point-min))))
>> > +    (pop-to-buffer buf)))
>> 
>> I am not sure about the erase-buffer in the above: do we definitely want
>> to remove all previous error information? For version mismatch possibly
>> we do but in patch 9 it is done for all show command-line error returns.
>
> Why wouldn't we want to use a cleared buffer in all cases?
> notmuch-pop-up-error is only ever used when a command terminates, so
> there's no danger of us clearing errors that the user hasn't seen yet.

Just to make sure I understand this: whenever an error occurs the error
popup appears so we see the message. Then the next error can safely
erase buffer before showing the new error message?

>> Incidentally why does show always pop-up an error but search only for
>> version-mismatches?
>
> Historical reasons, I suppose.  I was maintaining the status quo for
> search (which already had *some* error handling), but there was no
> error-handling status quo for show.  Probably search should be more
> vocal when the command fails.

Should notmuch-call-notmuch-process also be switched to this framework?
In particular that also puts errors in "*Notmuch errors*" so my earlier
concern may be valid in this case.

Best wishes

Mark
>
>> Otherwise this looks good to me (but I am not that familiar with lisp
>> error handling)
>> 
>> Best wishes
>> 
>> Mark
>> 
>> 
>> 
>> 
>> 
>> 
>> > +(defun notmuch-version-mismatch-error (exit-status)
>> > +  "Signal a schema version mismatch error.
>> > +
>> > +EXIT-STATUS must be the exit status of the notmuch CLI command,
>> > +and must have the value 20 or 21.  This function will pop up an
>> > +error buffer with a descriptive message and signal an error."
>> > +  (cond ((= exit-status 20)
>> > +	 (notmuch-pop-up-error "Error: Version mismatch.
>> > +Emacs requested an older output format than supported by the notmuch CLI.
>> > +You may need to restart Emacs or upgrade your notmuch Emacs package."))
>> > +	((= exit-status 21)
>> > +	 (notmuch-pop-up-error "Error: Version mismatch.
>> > +Emacs requested a newer output format than supported by the notmuch CLI.
>> > +You may need to restart Emacs or upgrade your notmuch package."))
>> > +	(t
>> > +	 (error "Bad exit status %d" exit-status)))
>> > +  (error "notmuch CLI version mismatch"))
>> > +
>> >  ;; Compatibility functions for versions of emacs before emacs 23.
>> >  ;;
>> >  ;; Both functions here were copied from emacs 23 with the following copyright:
>> > diff --git a/emacs/notmuch.el b/emacs/notmuch.el
>> > index f9454d8..e1f28ca 100644
>> > --- a/emacs/notmuch.el
>> > +++ b/emacs/notmuch.el
>> > @@ -644,6 +644,7 @@ of the result."
>> >  	(exit-status (process-exit-status proc))
>> >  	(never-found-target-thread nil))
>> >      (when (memq status '(exit signal))
>> > +      (catch 'return
>> >  	(kill-buffer (process-get proc 'parse-buf))
>> >  	(if (buffer-live-p buffer)
>> >  	    (with-current-buffer buffer
>> > @@ -655,8 +656,16 @@ of the result."
>> >  		      (insert "Incomplete search results (search process was killed).\n"))
>> >  		  (when (eq status 'exit)
>> >  		    (insert "End of search results.")
>> > -		    (unless (= exit-status 0)
>> > -		      (insert (format " (process returned %d)" exit-status)))
>> > +		    (cond ((or (= exit-status 20) (= exit-status 21))
>> > +			   (kill-buffer)
>> > +			   (condition-case err
>> > +			       (notmuch-version-mismatch-error exit-status)
>> > +			     ;; Strange things happen when you signal
>> > +			     ;; an error from a sentinel.
>> > +			     (error (throw 'return nil))))
>> > +			  ((/= exit-status 0)
>> > +			   (insert (format " (process returned %d)"
>> > +					   exit-status))))
>> >  		    (insert "\n")
>> >  		    (if (and atbob
>> >  			     (not (string= notmuch-search-target-thread "found")))
>> > @@ -664,7 +673,7 @@ of the result."
>> >  	      (when (and never-found-target-thread
>> >  		       notmuch-search-target-line)
>> >  		  (goto-char (point-min))
>> > -		  (forward-line (1- notmuch-search-target-line))))))))
>> > +		  (forward-line (1- notmuch-search-target-line)))))))))
>> >  
>> >  (defcustom notmuch-search-line-faces '(("unread" :weight bold)
>> >  				       ("flagged" :foreground "blue"))
>> > @@ -938,7 +947,7 @@ Other optional parameters are used as follows:
>> >  	(let ((proc (start-process
>> >  		     "notmuch-search" buffer
>> >  		     notmuch-command "search"
>> > -		     "--format=json"
>> > +		     "--format=json" "--use-schema=1"
>> >  		     (if oldest-first
>> >  			 "--sort=oldest-first"
>> >  		       "--sort=newest-first")
>> >
>> > _______________________________________________
>> > notmuch mailing list
>> > notmuch@notmuchmail.org
>> > http://notmuchmail.org/mailman/listinfo/notmuch
>
> -- 
> Austin Clements                                      MIT/'06/PhD/CSAIL
> amdragon@mit.edu                           http://web.mit.edu/amdragon
>        Somewhere in the dream we call reality you will find me,
>               searching for the reality we call dreams.