2 files changed, 10 insertions, 6 deletions

diff --git a/lisp/gnus/ChangeLog b/lisp/gnus/ChangeLog
index 5867a5c0bc9..8859ce8c4ad 100644
--- a/lisp/gnus/ChangeLog
+++ b/lisp/gnus/ChangeLog
@@ -81,6 +81,9 @@
 
 2010-10-06  Julien Danjou  <julien@danjou.info>
 
+        * gnus.el (gnus-expand-group-parameter): Only return and act on what
+        was matched.
+
         * sieve-manage.el: Update example in `Commentary'.
 
         * sieve.el (sieve-open-server): Use sieve-manage-authenticate.
diff --git a/lisp/gnus/gnus.el b/lisp/gnus/gnus.el
index 12215dee702..b62bf051c5d 100644
--- a/lisp/gnus/gnus.el
+++ b/lisp/gnus/gnus.el
@@ -3815,12 +3815,13 @@ You should probably use `gnus-find-method-for-group' instead."
 
 (defun gnus-expand-group-parameter (match value group)
   "Use MATCH to expand VALUE in GROUP."
-  (with-temp-buffer
-    (insert group)
-    (goto-char (point-min))
-    (while (re-search-forward match nil t)
-      (replace-match value))
-    (buffer-string)))
+  (let ((start (string-match match group)))
+    (if start
+        (let ((matched-string (substring group start (match-end 0))))
+          ;; Build match groups
+          (string-match match matched-string)
+          (replace-match value nil nil matched-string))
+      group)))
 
 (defun gnus-expand-group-parameters (match parameters group)
   "Go through PARAMETERS and expand them according to the match data."