Fix bug #15437 with mouse highlight on overlay strings.

 src/xdisp.c (mouse_face_from_string_pos): Fix off-by-one error in
 computing the end column of mouse-highlight that comes from
 display or overlay strings.

2 files changed, 11 insertions, 7 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 093368568c2..8483bdc6216 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,9 @@
 2013-09-23  Eli Zaretskii  <eliz@gnu.org>
 
+        * xdisp.c (mouse_face_from_string_pos): Fix off-by-one error in
+        computing the end column of mouse-highlight that comes from
+        display or overlay strings.  (Bug#15437)
+
         * conf_post.h (__has_builtin): Define to zero, if undefined, on
         all platforms, not just for clang.
 
diff --git a/src/xdisp.c b/src/xdisp.c
index bfd86758a1e..0575c7b3282 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -27381,7 +27381,7 @@ fast_find_string_pos (struct window *w, ptrdiff_t pos, Lisp_Object object,
 #endif  /* not used */
 
 /* Find the positions of the first and the last glyphs in window W's
-   current matrix that occlude positions [STARTPOS..ENDPOS] in OBJECT
+   current matrix that occlude positions [STARTPOS..ENDPOS) in OBJECT
    (assumed to be a string), and return in HLINFO's mouse_face_*
    members the pixel and column/row coordinates of those glyphs.  */
 
@@ -27397,7 +27397,7 @@ mouse_face_from_string_pos (struct window *w, Mouse_HLInfo *hlinfo,
   int found = 0;
 
   /* Find the glyph row with at least one position in the range
-     [STARTPOS..ENDPOS], and the first glyph in that row whose
+     [STARTPOS..ENDPOS), and the first glyph in that row whose
      position belongs to that range.  */
   for (r = MATRIX_FIRST_TEXT_ROW (w->current_matrix);
        r->enabled_p && r->y < yb;
@@ -27409,7 +27409,7 @@ mouse_face_from_string_pos (struct window *w, Mouse_HLInfo *hlinfo,
           e = g + r->used[TEXT_AREA];
           for (gx = r->x; g < e; gx += g->pixel_width, ++g)
             if (EQ (g->object, object)
-                && startpos <= g->charpos && g->charpos <= endpos)
+                && startpos <= g->charpos && g->charpos < endpos)
               {
                 hlinfo->mouse_face_beg_row
                   = MATRIX_ROW_VPOS (r, w->current_matrix);
@@ -27427,7 +27427,7 @@ mouse_face_from_string_pos (struct window *w, Mouse_HLInfo *hlinfo,
           g = e + r->used[TEXT_AREA];
           for ( ; g > e; --g)
             if (EQ ((g-1)->object, object)
-                && startpos <= (g-1)->charpos && (g-1)->charpos <= endpos)
+                && startpos <= (g-1)->charpos && (g-1)->charpos < endpos)
               {
                 hlinfo->mouse_face_beg_row
                   = MATRIX_ROW_VPOS (r, w->current_matrix);
@@ -27455,7 +27455,7 @@ mouse_face_from_string_pos (struct window *w, Mouse_HLInfo *hlinfo,
       found = 0;
       for ( ; g < e; ++g)
         if (EQ (g->object, object)
-            && startpos <= g->charpos && g->charpos <= endpos)
+            && startpos <= g->charpos && g->charpos < endpos)
           {
             found = 1;
             break;
@@ -27478,7 +27478,7 @@ mouse_face_from_string_pos (struct window *w, Mouse_HLInfo *hlinfo,
       e = g + r->used[TEXT_AREA];
       for ( ; e > g; --e)
         if (EQ ((e-1)->object, object)
-            && startpos <= (e-1)->charpos && (e-1)->charpos <= endpos)
+            && startpos <= (e-1)->charpos && (e-1)->charpos < endpos)
           break;
       hlinfo->mouse_face_end_col = e - g;
 
@@ -27493,7 +27493,7 @@ mouse_face_from_string_pos (struct window *w, Mouse_HLInfo *hlinfo,
       for (gx = r->x ; e < g; ++e)
         {
           if (EQ (e->object, object)
-              && startpos <= e->charpos && e->charpos <= endpos)
+              && startpos <= e->charpos && e->charpos < endpos)
             break;
           gx += e->pixel_width;
         }