* mail/rmail.el (rmail-set-message-counters):

Call rmail-set-message-counters-counter just once.
It returns # msgs after point.
(rmail-set-message-counters-counter):
Arg is now SPOT-TO-FIND.  Return # messages after that one.

* mail/rmail.el (rmail-forget-messages):
Ignore nil elt in rmail-message-vector.  Use dotimes.

2 files changed, 35 insertions, 21 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index ad18578e4c4..9bd9643568e 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -3,6 +3,9 @@
         * mail/rmail.el (rmail-get-attr-names):
         Accept an attribute header that is too short.
 
+        * mail/rmail.el (rmail-forget-messages):
+        Ignore nil elt in rmail-message-vector.  Use dotimes.
+
         * progmodes/compile.el (compilation-goto-locus):
         Use next-error-move-function.
 
diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index 2fd99fbd282..c61efeb30be 100644
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -2369,12 +2369,11 @@ change the invisible header text."
 (defun rmail-forget-messages ()
   (unwind-protect
       (if (vectorp rmail-message-vector)
-          (let* ((i 0)
-                 (v rmail-message-vector)
+          (let* ((v rmail-message-vector)
                  (n (length v)))
-            (while (< i n)
-              (move-marker (aref v i)  nil)
-              (setq i (1+ i)))))
+            (dotimes (i n)
+              (if (aref v i)
+                  (move-marker (aref v i)  nil)))))
     (setq rmail-message-vector nil)
     (setq rmail-msgref-vector nil)
     (setq rmail-deleted-vector nil)))
@@ -2440,20 +2439,25 @@ Output a helpful message unless NOMSG is non-nil."
         ;; the entry for message N+1, which marks
         ;; the end of message N.  (N = number of messages).
         (setq messages-head (list (point-marker)))
-        (rmail-set-message-counters-counter (min (point) point-save))
-        (setq messages-after-point total-messages)
+        (setq messages-after-point 
+              (or (rmail-set-message-counters-counter (min (point) point-save))
+                  0))
 
-        ;; Determine how many precede point.
-        (rmail-set-message-counters-counter)
         (setq rmail-total-messages total-messages)
         (setq rmail-current-message
               (min total-messages
                    (max 1 (- total-messages messages-after-point))))
-        (setq rmail-message-vector
-              (apply 'vector (cons (point-min-marker) messages-head))
-              rmail-deleted-vector (concat "0" deleted-head)
-              rmail-summary-vector (make-vector rmail-total-messages nil)
+
+        ;; Make an element 0 in rmail-message-vector and rmail-deleted-vector
+        ;; which will never be used.
+        (push nil messages-head)
+        (push ?0 deleted-head)
+        (setq rmail-message-vector (apply 'vector messages-head)
+              rmail-deleted-vector (concat deleted-head))
+
+        (setq rmail-summary-vector (make-vector rmail-total-messages nil)
               rmail-msgref-vector (make-vector (1+ rmail-total-messages) nil))
+
         (let ((i 0))
           (while (<= i rmail-total-messages)
             (aset rmail-msgref-vector i (list i))
@@ -2480,12 +2484,17 @@ the message.  Point is at the beginning of the message."
                     ?D
                   ?\s) deleted-head))))
 
-(defun rmail-set-message-counters-counter (&optional stop)
-  ;; Collect the start position for each message into 'messages-head.
-  (let ((start (point)))
-    (while (search-backward "\n\nFrom " stop t)
+(defun rmail-set-message-counters-counter (&optional spot-to-find)
+  "Collect the start positions of messages in list `messages-head'.
+Return the number of messages after the one containing SPOT-TO-FIND."
+  (let ((start (point))
+        messages-after-spot)
+    (while (search-backward "\n\nFrom " nil t)
       (forward-char 2)
       (when (looking-at rmail-unix-mail-delimiter)
+        (if (and (<= (point) spot-to-find)
+                 (null messages-after-spot))
+            (setq messages-after-spot total-messages))
         (rmail-collect-deleted start)
         (setq messages-head (cons (point-marker) messages-head)
               total-messages (1+ total-messages)
@@ -2494,13 +2503,15 @@ the message.  Point is at the beginning of the message."
         (if (zerop (% total-messages 20))
             (message "Counting messages...%d" total-messages))))
     ;; Handle the first message, maybe.
-    (if stop
-        (goto-char stop)
-      (goto-char (point-min)))
+    (goto-char (point-min))
     (unless (not (looking-at rmail-unix-mail-delimiter))
+      (if (and (<= (point) spot-to-find)
+               (null messages-after-spot))
+          (setq messages-after-spot total-messages))
       (rmail-collect-deleted start)
       (setq messages-head (cons (point-marker) messages-head)
-            total-messages (1+ total-messages)))))
+            total-messages (1+ total-messages)))
+    messages-after-spot))
 
 ;; Display a message.