Fix 2013-03-28T02:41:05Z!dmantipov@yandex.ru which brokes Fbuffer_swap_text.

* buffer.c (Fbuffer_swap_text): Adjust window start markers.
Fix comment.

2 files changed, 12 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 1e47fa0e1b6..fcc8bb5eaa3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -17,6 +17,8 @@
         which is verified by eassert.
         * editfns.c (save_excursion_save): Do not assume that
         selected_window always displays the buffer.
+        * buffer.c (Fbuffer_swap_text): Adjust window start markers.
+        Fix comment.
 
 2013-03-27  Stefan Monnier  <monnier@iro.umontreal.ca>
 
diff --git a/src/buffer.c b/src/buffer.c
index aa3fcf8c234..d02bcf7eceb 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2394,8 +2394,9 @@ DEFUN ("buffer-swap-text", Fbuffer_swap_text, Sbuffer_swap_text,
            BUF_MARKERS(buf) should either be for `buf' or dead.  */
         eassert (!m->buffer);
   }
-  { /* Some of the C code expects that w->buffer == w->pointm->buffer.
-       So since we just swapped the markers between the two buffers, we need
+  { /* Some of the C code expects that both window markers of a
+       live window points to that window's buffer.  So since we
+       just swapped the markers between the two buffers, we need
        to undo the effect of this swap for window markers.  */
     Lisp_Object w = Fselected_window (), ws = Qnil;
     Lisp_Object buf1, buf2;
@@ -2411,6 +2412,13 @@ DEFUN ("buffer-swap-text", Fbuffer_swap_text, Sbuffer_swap_text,
                        make_number
                        (BUF_BEGV (XBUFFER (XWINDOW (w)->buffer))),
                        XWINDOW (w)->buffer);
+        if (MARKERP (XWINDOW (w)->start)
+            && (EQ (XWINDOW (w)->buffer, buf1)
+                || EQ (XWINDOW (w)->buffer, buf2)))
+          Fset_marker (XWINDOW (w)->start,
+                       make_number
+                       (XBUFFER (XWINDOW (w)->buffer)->last_window_start),
+                       XWINDOW (w)->buffer);
         w = Fnext_window (w, Qt, Qt);
       }
   }