Fix redisplay crash (Bug#6177).

* xdisp.c (redisplay_window): After redisplay, check if point is
still valid before setting it (Bug#6177).

2 files changed, 15 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index d7128960af7..883d603bf35 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2010-05-27  Chong Yidong  <cyd@stupidchicken.com>
+
+        * xdisp.c (redisplay_window): After redisplay, check if point is
+        still valid before setting it (Bug#6177).
+
 2010-05-27  Glenn Morris  <rgm@gnu.org>
 
         * Makefile.in, autodeps.mk, deps.mk, ns.mk:
diff --git a/src/xdisp.c b/src/xdisp.c
index 699f375e2f4..31fa5f39d5f 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -14788,8 +14788,16 @@ redisplay_window (window, just_this_one_p)
         (*FRAME_TERMINAL (f)->redeem_scroll_bar_hook) (w);
     }
 
-  /* Restore current_buffer and value of point in it.  */
-  TEMP_SET_PT_BOTH (CHARPOS (opoint), BYTEPOS (opoint));
+  /* Restore current_buffer and value of point in it.  The window
+     update may have changed the buffer, so first make sure `opoint'
+     is still valid (Bug#6177).  */
+  if (CHARPOS (opoint) < BEGV)
+    TEMP_SET_PT_BOTH (BEGV, BEGV_BYTE);
+  else if (CHARPOS (opoint) > ZV)
+    TEMP_SET_PT_BOTH (Z, Z_BYTE);
+  else
+    TEMP_SET_PT_BOTH (CHARPOS (opoint), BYTEPOS (opoint));
+
   set_buffer_internal_1 (old);
   /* Avoid an abort in TEMP_SET_PT_BOTH if the buffer has become
      shorter.  This can be caused by log truncation in *Messages*. */