From fdafd487a90fbd4febe853971f238c5395c12542 Mon Sep 17 00:00:00 2001
From: Matthias Dahl <ml_emacs-lists@binary-island.eu>
Date: Sat, 5 Apr 2014 10:25:52 +0300
Subject: [PATCH] Fix bug #16378 with mishandling of empty faces.

 lisp/faces.el (face-spec-choose): Accept additional optional argument,
 whose value is returned if no matching attributes are found.
 (face-spec-recalc): Use the new optional argument when calling
 face-spec-choose.
---
 lisp/ChangeLog |  4 ++++
 lisp/faces.el  | 30 +++++++++++++++++++++---------
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index a74e121c6bd..bb283ab84df 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -3,6 +3,10 @@
 	* faces.el (face-spec-recalc): Call make-face-x-resource-internal
 	only when inhibit-x-resources is nil, and do that earlier in the
 	function.  Doc fix.  (Bug#16694)
+	(face-spec-choose): Accept additional optional argument, whose
+	value is returned if no matching attributes are found.
+	(face-spec-recalc): Use the new optional argument when calling
+	face-spec-choose.  (Bug#16378)
 
 2014-04-04  Tassilo Horn  <tsdh@gnu.org>
 
diff --git a/lisp/faces.el b/lisp/faces.el
index c6dd8d7a2d5..1255d7c9ff7 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -1512,13 +1512,15 @@ If FRAME is nil, the current FRAME is used."
     match))
 
 
-(defun face-spec-choose (spec &optional frame)
-  "Choose the proper attributes for FRAME, out of SPEC.
-If SPEC is nil, return nil."
+(defun face-spec-choose (spec &optional frame no-match-retval)
+  "Return the proper attributes for FRAME, out of SPEC.
+
+If no match is found or SPEC is nil, return nil, unless NO-MATCH-RETVAL
+is given, in which case return its value instead."
   (unless frame
     (setq frame (selected-frame)))
   (let ((tail spec)
-	result defaults)
+	result defaults match-found)
     (while tail
       (let* ((entry (pop tail))
 	     (display (car entry))
@@ -1538,9 +1540,18 @@ If SPEC is nil, return nil."
 	    (setq defaults thisval)
 	  ;; Otherwise, if it matches, use it.
 	  (when (face-spec-set-match-display display frame)
-	    (setq result thisval)
-	    (setq tail nil)))))
-    (if defaults (append result defaults) result)))
+	    (setq result thisval
+	          tail nil
+		  match-found t)))))
+    ;; If defaults have been found, it's safe to just append those to the result
+    ;; list (which at this point will be either nil or contain actual specs) and
+    ;; return it to the caller. Since there will most definitely be something to
+    ;; return in this case, there's no need to know/check if a match was found.
+    (if defaults
+	(append result defaults)
+      (if match-found
+	  result
+	no-match-retval))))
 
 
 (defun face-spec-reset-face (face &optional frame)
@@ -1635,11 +1646,12 @@ After the reset, the specs are applied from the following sources in this order:
   ;; If FACE is customized or themed, set the custom spec from
   ;; `theme-face' records.
   (let ((theme-faces (get face 'theme-face))
+	(no-match-found 0)
 	spec theme-face-applied)
     (if theme-faces
 	(dolist (elt (reverse theme-faces))
-	  (setq spec (face-spec-choose (cadr elt) frame))
-	  (when spec
+	  (setq spec (face-spec-choose (cadr elt) frame no-match-found))
+	  (unless (eq spec no-match-found)
 	    (face-spec-set-2 face frame spec)
 	    (setq theme-face-applied t))))
     ;; If there was a spec applicable to FRAME, that overrides the
-- 
2.39.2