Make `C-h b' work correctly in Gnus article buffer (bug#18257)

* lisp/gnus/gnus-art.el (gnus-article-describe-bindings):
Ignore summary commands that aren't bound to
gnus-article-read-summary-keys keys (bug#18257).

1 files changed, 6 insertions, 2 deletions

diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index a0f14402fbf..43e1231914c 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -6846,17 +6846,21 @@ then we display only bindings that start with that prefix."
   (let ((keymap (copy-keymap gnus-article-mode-map))
         (map (copy-keymap gnus-article-send-map))
         (sumkeys (where-is-internal 'gnus-article-read-summary-keys))
+        (summap (make-sparse-keymap))
         parent agent draft)
     (define-key keymap "S" map)
     (define-key map [t] nil)
+    (define-key summap [t] 'undefined)
     (with-current-buffer gnus-article-current-summary
+      (dolist (key sumkeys)
+        (define-key summap key (key-binding key (current-local-map))))
       (set-keymap-parent
        keymap
        (if (setq parent (keymap-parent gnus-article-mode-map))
            (prog1
                (setq parent (copy-keymap parent))
-             (set-keymap-parent parent (current-local-map)))
-         (current-local-map)))
+             (set-keymap-parent parent summap))
+         summap))
       (set-keymap-parent map (key-binding "S"))
       (let (key def gnus-pick-mode)
         (while sumkeys