Fix L2R code using bug #1220 as a test case.

 xdisp.c (mouse_face_from_buffer_pos): before_string and after_string
 are also relevant when they come from an overlay.

2 files changed, 17 insertions, 9 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 242018c4061..9b7c11d3bde 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2010-08-28  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (mouse_face_from_buffer_pos): Fix code using bug#1220 as
+        test case.
+
 2010-08-21  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (mouse_face_from_buffer_pos): Support mouse highlight in
diff --git a/src/xdisp.c b/src/xdisp.c
index 7fcbab718b1..c6d441fa6c1 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -23897,7 +23897,7 @@ mouse_face_from_buffer_pos (Lisp_Object window,
          between START_CHARPOS and END_CHARPOS, and highlight all the
          glyphs between those two.  This may cover more than just the
          text between START_CHARPOS and END_CHARPOS if the range of
-         characters strides the the bidi level boundary, e.g. if the
+         characters strides the bidi level boundary, e.g. if the
          beginning is in R2L text while the end is in L2R text or vice
          versa.  */
       if (!row->reversed_p)
@@ -23929,18 +23929,21 @@ mouse_face_from_buffer_pos (Lisp_Object window,
             {
               /* BEFORE_STRING or AFTER_STRING are only relevant if
                  they are present at buffer positions between
-                 START_CHARPOS and END_CHARPOS.  */
+                 START_CHARPOS and END_CHARPOS, or if they come from
+                 an overlay.  */
               if (EQ (glyph->object, before_string))
                 {
                   pos = string_buffer_position (w, before_string,
                                                 start_charpos);
-                  if (pos && pos >= start_charpos && pos < end_charpos)
+                  /* If pos == 0, it means before_string came from an
+                     overlay, not from a buffer position.  */
+                  if (!pos || pos >= start_charpos && pos < end_charpos)
                     break;
                 }
               else if (EQ (glyph->object, after_string))
                 {
                   pos = string_buffer_position (w, after_string, end_charpos);
-                  if (pos && pos >= start_charpos && pos < end_charpos)
+                  if (!pos || pos >= start_charpos && pos < end_charpos)
                     break;
                 }
               x += glyph->pixel_width;
@@ -24001,19 +24004,19 @@ mouse_face_from_buffer_pos (Lisp_Object window,
                       && end->charpos < end_charpos));
            --end)
         {
-          /* BEFORE_STRING or AFTER_STRING are only relevant if
-             they are present at buffer positions between
-             START_CHARPOS and END_CHARPOS.  */
+          /* BEFORE_STRING or AFTER_STRING are only relevant if they
+             are present at buffer positions between START_CHARPOS and
+             END_CHARPOS, or if they come from an overlay.  */
           if (EQ (end->object, before_string))
             {
               pos = string_buffer_position (w, before_string, start_charpos);
-              if (pos && pos >= start_charpos && pos < end_charpos)
+              if (!pos || pos >= start_charpos && pos < end_charpos)
                 break;
             }
           else if (EQ (end->object, after_string))
             {
               pos = string_buffer_position (w, after_string, end_charpos);
-              if (pos && pos >= start_charpos && pos < end_charpos)
+              if (!pos || pos >= start_charpos && pos < end_charpos)
                 break;
             }
         }