bug#9229: 24.0.50; Bidi problem with `cursor' property

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 03 Aug 2011 19:19:45 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 9229@debbugs.gnu.org
> 
> > From: Johan Bockgård <bojohan@gnu.org>
> > Date: Wed, 03 Aug 2011 16:29:52 +0200
> > 
> > 
> >     (let ((o (make-overlay (point-max) (point-max)))
> >           (s (make-string (+ 5 (window-width)) ?-)))
> >       (put-text-property 0 1 'cursor t s)
> >       (overlay-put o 'after-string s)
> >       (goto-char (point-max)))
> > 
> > The cursor is expected to be displayed before the overlay, but is
> > displayed after it.
> > 
> > (This bug makes icomplete-mode very confusing to use.)

Does the patch below give good results?  If it solves this particular
problem, please try it in your regular use for a day or two, and see
if there are any adverse effects.  If you don't spot any trouble, I
will install this on the trunk.

Thanks.

Here's the patch to try:

=== modified file 'src/xdisp.c'
--- src/xdisp.c	2011-08-03 05:24:30 +0000
+++ src/xdisp.c	2011-08-03 19:04:49 +0000
@@ -13706,14 +13706,15 @@ set_cursor_from_row (struct window *w, s
       w->cursor.vpos >= 0
       /* that candidate is not the row we are processing */
       && MATRIX_ROW (matrix, w->cursor.vpos) != row
-      /* the row we are processing is part of a continued line */
-      && (row->continued_p || MATRIX_ROW_CONTINUATION_LINE_P (row))
       /* Make sure cursor.vpos specifies a row whose start and end
 	 charpos occlude point.  This is because some callers of this
 	 function leave cursor.vpos at the row where the cursor was
 	 displayed during the last redisplay cycle.  */
       && MATRIX_ROW_START_CHARPOS (MATRIX_ROW (matrix, w->cursor.vpos)) <= pt_old
-      && pt_old < MATRIX_ROW_END_CHARPOS (MATRIX_ROW (matrix, w->cursor.vpos)))
+      && (pt_old < MATRIX_ROW_END_CHARPOS (MATRIX_ROW (matrix, w->cursor.vpos))
+	  /* the entire line is from display string */
+	  || (pt_old == MATRIX_ROW_START_CHARPOS (MATRIX_ROW (matrix, w->cursor.vpos))
+	      && pt_old == MATRIX_ROW_END_CHARPOS (MATRIX_ROW (matrix, w->cursor.vpos)))))
     {
       struct glyph *g1 =
 	MATRIX_ROW_GLYPH_START (matrix, w->cursor.vpos) + w->cursor.hpos;
@@ -13722,15 +13723,20 @@ set_cursor_from_row (struct window *w, s
       if (!(row->reversed_p ? glyph > glyphs_end : glyph < glyphs_end))
 	return 0;
       /* Keep the candidate whose buffer position is the closest to
-	 point.  */
+	 point or has the `cursor' property.  */
       if (/* previous candidate is a glyph in TEXT_AREA of that row */
 	  w->cursor.hpos >= 0
 	  && w->cursor.hpos < MATRIX_ROW_USED (matrix, w->cursor.vpos)
-	  && BUFFERP (g1->object)
-	  && (g1->charpos == pt_old /* an exact match always wins */
-	      || (BUFFERP (glyph->object)
-		  && eabs (g1->charpos - pt_old)
-		   < eabs (glyph->charpos - pt_old))))
+	  && ((BUFFERP (g1->object)
+	       && (g1->charpos == pt_old /* an exact match always wins */
+		   || (BUFFERP (glyph->object)
+		       && eabs (g1->charpos - pt_old)
+		       < eabs (glyph->charpos - pt_old))))
+	      /* previous candidate is a glyph from a string that has
+		 a non-nil `cursor' property */
+	      || (STRINGP (g1->object)
+		  && !NILP (Fget_char_property (make_number (g1->charpos),
+						Qcursor, g1->object)))))
 	return 0;
       /* If this candidate gives an exact match, use that.  */
       if (!(BUFFERP (glyph->object) && glyph->charpos == pt_old)