master bb3b099: fix bug#39344

[Sam Steingold]

branch: master
commit bb3b0990d8505342ae14841144778df9e650ebdc
Author: Sam Steingold <address@hidden>
Commit: Sam Steingold <address@hidden>

    fix bug#39344
    
    * gnus.el (gnus-add-buffer): Use `cl-pushnew' instead of `push' to
      avoid duplicate entries.
---
 lisp/gnus/gnus.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/gnus/gnus.el b/lisp/gnus/gnus.el
index 6df26b4..caeab7f 100644
--- a/lisp/gnus/gnus.el
+++ b/lisp/gnus/gnus.el
@@ -660,7 +660,7 @@ be used directly.")
 (defun gnus-add-buffer ()
   "Add the current buffer to the list of Gnus buffers."
   (gnus-prune-buffers)
-  (push (current-buffer) gnus-buffers))
+  (cl-pushnew (current-buffer) gnus-buffers))
 
 (defmacro gnus-kill-buffer (buffer)
   "Kill BUFFER and remove from the list of Gnus buffers."