1 files changed, 7 insertions, 1 deletions

diff --git a/lisp/gnus/gnus-agent.el b/lisp/gnus/gnus-agent.el
index 97df48b4608..32d0a85d004 100644
--- a/lisp/gnus/gnus-agent.el
+++ b/lisp/gnus/gnus-agent.el
@@ -3627,7 +3627,7 @@ has been fetched."
           (when fetched-headers
             (setq headers
                   (delete-dups
-                   (sort (append headers fetched-headers)
+                   (sort (append headers (copy-sequence fetched-headers))
                          (lambda (l r)
                            (< (mail-header-number l)
                               (mail-header-number r))))))
@@ -3636,8 +3636,14 @@ has been fetched."
             (let ((coding-system-for-write
                    gnus-agent-file-coding-system))
               (with-current-buffer gnus-agent-overview-buffer
+                ;; We stick the new headers in at the end, then
+                ;; re-sort the whole buffer with
+                ;; `sort-numeric-fields'.  If this turns out to be
+                ;; slow, we could consider a loop to add the headers
+                ;; in sorted order to begin with.
                 (goto-char (point-max))
                 (mapc #'nnheader-insert-nov fetched-headers)
+                (sort-numeric-fields 1 (point-min) (point-max))
                 (gnus-agent-check-overview-buffer)
                 (write-region (point-min) (point-max) file nil 'silent)
                 (gnus-agent-update-view-total-fetched-for group t)