Fix bug #14170 with window-end returning a stale value.

This bug was introduced in 2012-10-15T09:03:56Z!rudalics@gmx.at
while solving bug #12600.

 src/window.c (Fwindow_end): Test more flags, including the buffer's
 last_overlay_modified flag, to determine whether the window's
 display is really up-to-date.  Prevents the function from
 returning a stale value.
 (Fwindow_line_height): Fix the test for up-to-date-ness of the
 current matrix.

2 files changed, 18 insertions, 3 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index ff6b9508d62..7f4c59b8eb4 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2013-04-11  Eli Zaretskii  <eliz@gnu.org>
+
+        * window.c (Fwindow_end): Test more flags, including the buffer's
+        last_overlay_modified flag, to determine whether the window's
+        display is really up-to-date.  Prevents the function from
+        returning a stale value.  (Bug#14170)
+        (Fwindow_line_height): Fix the test for up-to-date-ness of the
+        current matrix.
+
 2013-04-10  Eli Zaretskii  <eliz@gnu.org>
 
         * frame.c (do_switch_frame): Mark the TTY frame we switch to as
diff --git a/src/window.c b/src/window.c
index 2ddf742be99..fe5b5ec1e6e 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1493,7 +1493,12 @@ if it isn't already recorded.  */)
   b = XBUFFER (buf);
 
   if (! NILP (update)
-      && (windows_or_buffers_changed || !w->window_end_valid)
+      && (windows_or_buffers_changed
+          || !w->window_end_valid
+          || b->clip_changed
+          || b->prevent_redisplay_optimizations_p
+          || w->last_modified < BUF_MODIFF (b)
+          || w->last_overlay_modified < BUF_OVERLAY_MODIFF (b))
       && !noninteractive)
     {
       struct text_pos startp;
@@ -1702,8 +1707,9 @@ Return nil if window display is not up-to-date.  In that case, use
 
   /* Fail if current matrix is not up-to-date.  */
   if (!w->window_end_valid
-      || current_buffer->clip_changed
-      || current_buffer->prevent_redisplay_optimizations_p
+      || windows_or_buffers_changed
+      || b->clip_changed
+      || b->prevent_redisplay_optimizations_p
       || w->last_modified < BUF_MODIFF (b)
       || w->last_overlay_modified < BUF_OVERLAY_MODIFF (b))
     return Qnil;