Fix the expunge command so that the current message index is correct.

* pmail.el (pmail-expunge-counter): New variable
  (pmail-set-attribute): Canonicalize the calling sequence to index, attribute, state.
  (pmail-show-message, pmail-delete-message, pmail-undelete-previous-message,
   pmail-delete-forward, pmail-mark-message): Use the new canonical calling sequence.
  (pmail-only-expunge): Use the expunge counter to update the current message index.
  (pmail-expunge-callback): Simplify.  Just count the expunged messages with a lower
   index than the current message index.

* pmaildesc.el (pmail-desc-get-previous): Fix an "off by one" issue.
  (pmail-desc-set-attribute): Canonicalize the calling sequence to index, attribute, state.

* pmailout.el (pmail-output-body-to-file): Use the canonical calling sequence.

3 files changed, 22 insertions, 20 deletions

diff --git a/lisp/mail/pmail.el b/lisp/mail/pmail.el
index cfa6c3f95ad..38a6a2cd6c5 100644
--- a/lisp/mail/pmail.el
+++ b/lisp/mail/pmail.el
@@ -186,6 +186,11 @@ please report it with \\[report-emacs-bug].")
 
 (defvar pmail-encoded-remote-password nil)
 
+(defvar pmail-expunge-counter 0
+  "A counter used to keep track of the number of expunged
+messages with a lower message number than the current message
+index.")
+
 (defcustom pmail-preserve-inbox nil
   "*Non-nil means leave incoming mail in the user's inbox--don't delete it."
   :type 'boolean
@@ -1908,7 +1913,7 @@ default, the current message is changed."
       (let ((attr-index (pmail-desc-get-attr-index attr)))
         (set-buffer pmail-buffer)
         (or msgnum (setq msgnum pmail-current-message))
-        (pmail-desc-set-attribute attr-index state msgnum)
+        (pmail-desc-set-attribute msgnum attr-index state)
         ;; Deal with the summary buffer.
         (when pmail-summary-buffer
           (pmail-summary-update msgnum))))))
@@ -2143,7 +2148,7 @@ If NO-SUMMARY is non-nil, then do not update the summary buffer."
         ;; Clear the "unseen" attribute when we show a message, unless
         ;; it is already cleared.
         (when (pmail-desc-attr-p pmail-desc-unseen-index n)
-          (pmail-desc-set-attribute pmail-desc-unseen-index nil n))
+          (pmail-desc-set-attribute n pmail-desc-unseen-index nil))
         (pmail-display-labels)
         ;; Deal with MIME
         (if (eq pmail-enable-mime t)
@@ -2554,7 +2559,7 @@ If N is negative, go forwards instead."
 (defun pmail-delete-message ()
   "Delete this message and stay on it."
   (interactive)
-  (pmail-desc-set-attribute pmail-desc-deleted-index t pmail-current-message)
+  (pmail-desc-set-attribute pmail-current-message pmail-desc-deleted-index t)
   (run-hooks 'pmail-delete-message-hook)
   (pmail-show-message pmail-current-message))
 
@@ -2568,7 +2573,7 @@ If N is negative, go forwards instead."
       (setq msg (1- msg)))
     (if (= msg 0)
         (error "No previous deleted message")
-      (pmail-desc-set-attribute pmail-desc-deleted-index nil msg)
+      (pmail-desc-set-attribute msg pmail-desc-deleted-index nil)
       (pmail-show-message msg)
       (if (pmail-summary-exists)
           (save-excursion
@@ -2584,7 +2589,7 @@ With prefix argument, delete and move backward.
 
 Returns t if a new message is displayed after the delete, or nil otherwise."
   (interactive "P")
-  (pmail-desc-set-attribute pmail-desc-deleted-index t pmail-current-message)
+  (pmail-desc-set-attribute pmail-current-message pmail-desc-deleted-index t)
   (run-hooks 'pmail-delete-message-hook)
   (let ((del-msg pmail-current-message))
     (if (pmail-summary-exists)
@@ -2621,7 +2626,9 @@ See also user-option `pmail-confirm-expunge'."
   (or (eq buffer-undo-list t) (setq buffer-undo-list nil))
   ;; Remove the messages from the buffer and from the Pmail message
   ;; descriptor vector.
+  (setq pmail-expunge-counter 0)
   (pmail-desc-prune-deleted-messages 'pmail-expunge-callback)
+  (setq pmail-current-message (- pmail-current-message pmail-expunge-counter))
   ;; Deal with the summary buffer and update
   ;; the User status.
   (let* ((omax (- (buffer-size) (point-max)))
@@ -2650,13 +2657,9 @@ See also user-option `pmail-confirm-expunge'."
   message counter."
   ;; Process the various possible states to set the current message
   ;; counter.
-  (setq pmail-total-messages (1- pmail-total-messages)
-        pmail-current-message
-        (cond
-         ((= 0 pmail-total-messages) 0)
-         ((> pmail-current-message n) (pmail-desc-get-previous pmail-desc-deleted-index n))
-         ((> pmail-current-message n) 0)
-         (t pmail-current-message))))
+  (setq pmail-total-messages (1- pmail-total-messages))
+  (if (>= pmail-current-message n)
+      (setq pmail-expunge-counter (1+ pmail-expunge-counter))))
 
 ;;; mbox: ready
 (defun pmail-expunge ()
@@ -2793,7 +2796,7 @@ message buffers.  MSGNUM-LIST is a list of the form (MSGNUM)."
     (let ((n (car msgnum-list)))
       (set-buffer pmail-buffer)
       (pmail-narrow-to-message n)
-      (pmail-desc-set-attribute attr-index t n))))
+      (pmail-desc-set-attribute n attr-index t))))
 
 (defun pmail-narrow-to-message (n)
   "Narrow the current (pmail) buffer to bracket message N."
diff --git a/lisp/mail/pmaildesc.el b/lisp/mail/pmaildesc.el
index a63ea5cb207..9372be8ca20 100644
--- a/lisp/mail/pmaildesc.el
+++ b/lisp/mail/pmaildesc.el
@@ -355,18 +355,18 @@ This includes the attributes."
        (nth pmail-desc-date-index (pmail-desc-get-descriptor n))))
 
 (defun pmail-desc-get-previous (n attr-index &optional sense)
-  "Return the index for the previous matching descriptor.
+  "Return the message index for the previous matching descriptor.
 Starting with descriptor at index N locate the first previous
 descriptor such that the attribute ATTR is set.  SENSE, if
 non-null will reverse the sense of the attribute test."
   (let ((index (1- n)) flag result)
     (while (and (> index 0) (not result))
-      (if (listp (aref pmail-desc-vector index))
-          (setq result (pmail-desc-get-match-index attr-index sense index)))
+      (if (listp (aref pmail-desc-vector (1- index)))
+          (setq result (pmail-desc-get-match-index index attr-index sense)))
       (setq index (1- index)))
     (or result 0)))
 
-(defun pmail-desc-get-match-index (attr-index sense n)
+(defun pmail-desc-get-match-index (n attr-index sense)
   "Return the index N if the associated descriptor has a matching
 attribute, nil otherwise.  The attribute value must be set if
 SENSE is nil, or unset if SENSE is non-nil."
@@ -426,7 +426,7 @@ after a message has been deleted.."
           (vconcat (delq t (append pmail-desc-vector nil))))
     result))
 
-(defun pmail-desc-set-attribute (attr-index state n)
+(defun pmail-desc-set-attribute (n attr-index state)
   "Set the attribute denoted by ATTR-INDEX in message N according to STATE.
 If STATE is non-nil the attribute will be set to the single character code
 associated with ATTR-INDEX in pmail-desc-attr-alist, otherwise the attribute is
diff --git a/lisp/mail/pmailout.el b/lisp/mail/pmailout.el
index d8e71646f7a..4d776bf357d 100644
--- a/lisp/mail/pmailout.el
+++ b/lisp/mail/pmailout.el
@@ -244,8 +244,7 @@ FILE-NAME defaults, interactively, from the Subject field of the message."
          (error "Operation aborted"))
     (write-region (point) (point-max) file-name)
     (when (equal major-mode 'pmail-mode)
-      (pmail-desc-set-attribute pmail-desc-stored-index
-                                t pmail-current-message)))
+      (pmail-desc-set-attribute pmail-current-message pmail-desc-stored-index t)))
   (when pmail-delete-after-output
     (pmail-delete-forward)))