Fix part 1 of bug #9771 with assertion violation in move_it_by_lines.

 src/xdisp.c (move_it_vertically_backward): Don't look for character position
 immediately after the newline when in a continuation line.

2 files changed, 7 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 53e67a30c38..07b0418b399 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -3,6 +3,9 @@
         * xdisp.c (push_display_prop): Determine whether to record string
         or buffer position by IT->string, not by IT->method.  Allow
         GET_FROM_DISPLAY_VECTOR as IT->method on entry.  (Bug#9771, part 4)
+        (move_it_vertically_backward): Don't look for character position
+        immediately after the newline when in a continuation line.
+        (Bug#9771, part 1)
 
 2011-10-15  Martin Rudalics  <rudalics@gmx.at>
 
diff --git a/src/xdisp.c b/src/xdisp.c
index e796eb98f19..43907ccc03a 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -8768,7 +8768,10 @@ move_it_vertically_backward (struct it *it, int dy)
          reordering.  We want to get to the character position
          that is immediately after the newline of the previous
          line.  */
-      if (it->bidi_p && IT_CHARPOS (*it) > BEGV
+      if (it->bidi_p
+          && !it->continuation_lines_width
+          && !STRINGP (it->string)
+          && IT_CHARPOS (*it) > BEGV
           && FETCH_BYTE (IT_BYTEPOS (*it) - 1) != '\n')
         {
           EMACS_INT nl_pos =