(face-spec-set): Interpret a nil in specs for

foreground and background colors as `unspecified', for
compatibility with 20.x.

1 files changed, 4 insertions, 0 deletions

diff --git a/lisp/faces.el b/lisp/faces.el
index e93bc2ae518..491410992e9 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -1230,6 +1230,10 @@ If SPEC is nil, do nothing."
         (case attribute
           (:bold (setq attribute :weight value (if value 'bold 'normal)))
           (:italic (setq attribute :slant value (if value 'italic 'normal)))
+          ((:foreground :background)
+           ;; Compatibility with 20.x.  Some bogus face specs seem to 
+           ;; exist containing things like `:foreground nil'.
+           (if (null value) (setq value 'unspecified)))
           (t (unless (assq attribute face-x-resources)
                (setq attribute nil))))
         (when attribute