[PATCH 07/10] emacs: Use --use-schema for search

[Austin Clements]

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)))
+
+(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")
-- 
1.7.10.4