emacs: Prefer '[No Subject]' to blank subjects.

emacs/notmuch-lib.el

@@ -133,6 +133,15 @@ the user hasn't set this variable with the old or new value."
   (interactive)
   (kill-buffer (current-buffer)))
 
+(defun notmuch-prettify-subject (subject)
+  ;; This function is used by `notmuch-search-process-filter' which
+  ;; requires that we not disrupt its' matching state.
+  (save-match-data
+    (if (and subject
+	     (string-match "^[ \t]*$" subject))
+	"[No Subject]"
+      subject)))
+
 ;;
 
 (defun notmuch-common-do-stash (text)

emacs/notmuch-print.el

@@ -19,6 +19,8 @@
 ;;
 ;; Authors: David Edmondson <dme@dme.org>
 
+(require 'notmuch-lib)
+
 (declare-function notmuch-show-get-prop "notmuch-show" (prop &optional props))
 
 (defcustom notmuch-print-mechanism 'notmuch-print-lpr
@@ -58,14 +60,16 @@ Optional OUTPUT allows passing a list of flags to muttprint."
 
 (defun notmuch-print-ps-print (msg)
   "Print a message buffer using the ps-print package."
-  (let ((subject (plist-get (notmuch-show-get-prop :headers msg) :Subject)))
+  (let ((subject (notmuch-prettify-subject
+		  (plist-get (notmuch-show-get-prop :headers msg) :Subject))))
     (rename-buffer subject t)
     (ps-print-buffer)))
 
 (defun notmuch-print-ps-print/evince (msg)
   "Preview a message buffer using ps-print and evince."
   (let ((ps-file (make-temp-file "notmuch"))
-	(subject (plist-get (notmuch-show-get-prop :headers msg) :Subject)))
+	(subject (notmuch-prettify-subject
+		  (plist-get (notmuch-show-get-prop :headers msg) :Subject))))
     (rename-buffer subject t)
     (ps-print-buffer ps-file)
     (notmuch-print-run-evince ps-file)))

emacs/notmuch-show.el

@@ -1018,7 +1018,7 @@ buffer."
       (notmuch-show-next-open-message))
 
     ;; Set the header line to the subject of the first open message.
-    (setq header-line-format (notmuch-show-strip-re (notmuch-show-get-subject)))
+    (setq header-line-format (notmuch-show-strip-re (notmuch-show-get-pretty-subject)))
 
     (notmuch-show-mark-read)))
 
@@ -1250,6 +1250,9 @@ Some useful entries are:
 (defun notmuch-show-get-depth ()
   (notmuch-show-get-prop :depth))
 
+(defun notmuch-show-get-pretty-subject ()
+  (notmuch-prettify-subject (notmuch-show-get-subject)))
+
 (defun notmuch-show-set-tags (tags)
   "Set the tags of the current message."
   (notmuch-show-set-prop :tags tags)

emacs/notmuch.el

@@ -467,18 +467,14 @@ Complete list of currently available key bindings:
   "Display the currently selected thread."
   (interactive "P")
   (let ((thread-id (notmuch-search-find-thread-id))
-	(subject (notmuch-search-find-subject)))
+	(subject (notmuch-prettify-subject (notmuch-search-find-subject))))
     (if (> (length thread-id) 0)
-	(progn
-	  (if (string-match "^[ \t]*$" subject)
-	      (setq subject "[No Subject]"))
-
-	  (notmuch-show thread-id
-			(current-buffer)
-			notmuch-search-query-string
-			;; Name the buffer based on the subject.
-			(concat "*" (truncate-string-to-width subject 30 nil nil t) "*")
-			crypto-switch))
+	(notmuch-show thread-id
+		      (current-buffer)
+		      notmuch-search-query-string
+		      ;; Name the buffer based on the subject.
+		      (concat "*" (truncate-string-to-width subject 30 nil nil t) "*")
+		      crypto-switch)
       (message "End of search results."))))
 
 (defun notmuch-search-reply-to-thread (&optional prompt-for-sender)
@@ -853,7 +849,8 @@ non-authors is found, assume that all of the authors match."
 		      (if (/= (match-beginning 1) line)
 			  (insert (concat "Error: Unexpected output from notmuch search:\n" (substring string line (match-beginning 1)) "\n")))
 		      (let ((beg (point)))
-			(notmuch-search-show-result date count authors subject tags)
+			(notmuch-search-show-result date count authors
+						    (notmuch-prettify-subject subject) tags)
 			(notmuch-search-color-line beg (point) tag-list)
 			(put-text-property beg (point) 'notmuch-search-thread-id thread-id)
 			(put-text-property beg (point) 'notmuch-search-authors authors)