Fix vertical-motion and posn-at-point when word-wrap is on (Bug#19769)

 src/xdisp.c (move_it_in_display_line_to): Handle the case where the
 last character of a screen line is whitespace, and we are under
 word-wrap with overflow-newline-into-fringe turned on.

2 files changed, 37 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 8e7ab9363f6..135f28fb20f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2015-02-05  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (move_it_in_display_line_to): Handle the case where the
+        last character of a screen line is whitespace, and we are under
+        word-wrap with overflow-newline-into-fringe turned on.
+        (Bug#19769)
+
 2015-02-03  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (handle_stop, handle_single_display_spec)
diff --git a/src/xdisp.c b/src/xdisp.c
index 5e552ca2fdb..8cb43538dcc 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -8798,7 +8798,16 @@ move_it_in_display_line_to (struct it *it,
                           if (BUFFER_POS_REACHED_P ())
                             {
                               if (it->line_wrap != WORD_WRAP
-                                  || wrap_it.sp < 0)
+                                  || wrap_it.sp < 0
+                                  /* If we've just found whitespace to
+                                     wrap, effectively ignore the
+                                     previous wrap point -- it is no
+                                     longer relevant, but we won't
+                                     have an opportunity to update it,
+                                     since we've reached the edge of
+                                     this screen line.  */
+                                  || (may_wrap
+                                      && IT_OVERFLOW_NEWLINE_INTO_FRINGE (it)))
                                 {
                                   it->hpos = hpos_before_this_char;
                                   it->current_x = x_before_this_char;
@@ -8862,7 +8871,26 @@ move_it_in_display_line_to (struct it *it,
                   else
                     IT_RESET_X_ASCENT_DESCENT (it);
 
-                  if (wrap_it.sp >= 0)
+                  /* If the screen line ends with whitespace, and we
+                     are under word-wrap, don't use wrap_it: it is no
+                     longer relevant, but we won't have an opportunity
+                     to update it, since we are done with this screen
+                     line.  */
+                  if (may_wrap && IT_OVERFLOW_NEWLINE_INTO_FRINGE (it))
+                    {
+                      /* If we've found TO_X, go back there, as we now
+                         know the last word fits on this screen line.  */
+                      if ((op & MOVE_TO_X) && new_x == it->last_visible_x
+                          && atx_it.sp >= 0)
+                        {
+                          RESTORE_IT (it, &atx_it, atx_data);
+                          atpos_it.sp = -1;
+                          atx_it.sp = -1;
+                          result = MOVE_X_REACHED;
+                          break;
+                        }
+                    }
+                  else if (wrap_it.sp >= 0)
                     {
                       RESTORE_IT (it, &wrap_it, wrap_data);
                       atpos_it.sp = -1;