[PATCH 3/6] Add `gnus-select-group-with-message-id'

[Dave Abrahams <dave@boostpro.com>]

---
 lisp/gnus-int.el |   43 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/lisp/gnus-int.el b/lisp/gnus-int.el
index 2e10263..048f442 100644
--- a/lisp/gnus-int.el
+++ b/lisp/gnus-int.el
@@ -531,6 +531,49 @@ If BUFFER, insert the article in that group."
 	     header
 	     (gnus-group-real-name group))))
 
+(defun gnus-select-group-with-message-id (group message-id)
+  "Activate and select GROUP with the given MESSAGE-ID selected.
+Returns the article number of the message.
+
+If GROUP is not already selected, the message will be the only one in
+the group's summary.
+"
+  ;; TODO: is there a way to know at this point whether the group will
+  ;; be newly-selected?  If so we could clean up the logic at the end
+  ;;
+  ;; save the new group's display parameter, if any, so we
+  ;; can replace it temporarily with zero.
+  (let ((saved-display
+         (gnus-group-get-parameter group 'display :allow-list)))
+
+    ;; Tell gnus we really don't want any articles 
+    (gnus-group-set-parameter group 'display 0)
+
+    (unwind-protect
+        (gnus-summary-read-group-1
+         group (not :show-all) :no-article (not :kill-buffer)
+         ;; The combination of no-display and this dummy list of
+         ;; articles to select somehow makes it possible to open a
+         ;; group with no articles in it.  Black magic.
+         :no-display '(-1); select-articles
+         )
+      ;; Restore the new group's display parameter
+      (gnus-group-set-parameter group 'display saved-display)))
+
+  ;; The summary buffer was suppressed by :no-display above.
+  ;; Create it now and insert the message
+  (let ((group-is-new (gnus-summary-setup-buffer group)))
+    (condition-case err
+        (let ((article-number 
+               (gnus-summary-insert-subject message-id)))
+          (unless article-number
+            (signal 'error "message-id not in group"))
+          (gnus-summary-select-article nil nil nil article-number)
+          article-number)
+      ;; Clean up the new summary and propagate the error
+      (error (when group-is-new (gnus-summary-exit))
+             (apply 'signal err)))))
+
 (defun gnus-warp-to-article ()
   "Warps from an article in a virtual group to the article in its
 real group. Does nothing on a real group."
-- 
1.7.6.1