1 files changed, 23 insertions, 4 deletions

diff --git a/src/dispnew.c b/src/dispnew.c
index 7f795a4dc40..dc109883b53 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -935,6 +935,10 @@ adjust_window_charstarts (w, vpos, adjust)
     }
 }
 
+/* Check the charstarts values in the area of window W
+   for internal consistency.  We cannot check that they are "right";
+   we can only look for something nonsensical.  */
+
 verify_charstarts (w)
      struct window *w;
 {
@@ -945,17 +949,32 @@ verify_charstarts (w)
   int left = XFASTINT (w->left);
   int right = left + window_internal_width (w);
   int next_line;
+  int truncate = (XINT (w->hscroll)
+                  || (truncate_partial_width_windows
+                      && (XFASTINT (w->width) < FRAME_WIDTH (f)))
+                  || !NILP (XBUFFER (w->buffer)->truncate_lines));
 
   for (i = top; i < bottom; i++)
     {
       int j;
       int last;
-      int *charstart
-        = FRAME_CURRENT_GLYPHS (XFRAME (WINDOW_FRAME (w)))->charstarts[i];
+      int *charstart = FRAME_CURRENT_GLYPHS (f)->charstarts[i];
 
       if (i != top)
-        if (charstart[left] != next_line)
-          abort ();
+        {
+          if (truncate)
+            {
+              /* If we are truncating lines, allow a jump
+                 in charstarts from one line to the next.  */
+              if (charstart[left] < next_line)
+                abort ();
+            }
+          else
+            {
+              if (charstart[left] != next_line)
+                abort ();
+            }
+        }
 
       for (j = left; j < right; j++)
         if (charstart[j] > 0)