In split-window-below fix handling of split-window-keep-point (Bug#10971).

* window.el (split-window-below): Fix bug in case where
split-window-keep-point is nil (Bug#10971).

2 files changed, 27 insertions, 17 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 56ebb5fc948..50e012ad77b 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2012-03-11  Martin Rudalics  <rudalics@gmx.at>
+
+        * window.el (split-window-below): Fix bug in case where
+        split-window-keep-point is nil (Bug#10971).
+
 2012-03-11  Juri Linkov  <juri@jurta.org>
 
         * replace.el (replace-highlight): Set isearch-word to nil
diff --git a/lisp/window.el b/lisp/window.el
index edd8a113876..f79041e0e6c 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -3273,7 +3273,7 @@ Otherwise, the window starts are chosen so as to minimize the
 amount of redisplay; this is convenient on slow terminals."
   (interactive "P")
   (let ((old-window (selected-window))
-        (old-point (point))
+        (old-point (window-point-1))
         (size (and size (prefix-numeric-value size)))
         moved-by-window-height moved new-window bottom)
     (when (and size (< size 0) (< (- size) window-min-height))
@@ -3282,22 +3282,27 @@ amount of redisplay; this is convenient on slow terminals."
     (setq new-window (split-window nil size))
     (unless split-window-keep-point
       (with-current-buffer (window-buffer)
-        (goto-char (window-start))
-        (setq moved (vertical-motion (window-height)))
-        (set-window-start new-window (point))
-        (when (> (point) (window-point new-window))
-          (set-window-point new-window (point)))
-        (when (= moved (window-height))
-          (setq moved-by-window-height t)
-          (vertical-motion -1))
-        (setq bottom (point)))
-      (and moved-by-window-height
-           (<= bottom (point))
-           (set-window-point old-window (1- bottom)))
-      (and moved-by-window-height
-           (<= (window-start new-window) old-point)
-           (set-window-point new-window old-point)
-           (select-window new-window)))
+        ;; Use `save-excursion' around vertical movements below
+        ;; (Bug#10971).  Note: When the selected window's buffer has a
+        ;; header line, up to two lines of the buffer may not show up
+        ;; in the resulting configuration.
+        (save-excursion
+          (goto-char (window-start))
+          (setq moved (vertical-motion (window-height)))
+          (set-window-start new-window (point))
+          (when (> (point) (window-point new-window))
+            (set-window-point new-window (point)))
+          (when (= moved (window-height))
+            (setq moved-by-window-height t)
+            (vertical-motion -1))
+          (setq bottom (point)))
+        (and moved-by-window-height
+             (<= bottom (point))
+             (set-window-point-1 old-window (1- bottom)))
+        (and moved-by-window-height
+             (<= (window-start new-window) old-point)
+             (set-window-point new-window old-point)
+             (select-window new-window))))
     ;; Always copy quit-restore parameter in interactive use.
     (let ((quit-restore (window-parameter old-window 'quit-restore)))
       (when quit-restore