[Emacs-diffs] /srv/bzr/emacs/trunk r108423: Do not avoid creating empty evaporating overlays (Bug#9642).

[Paul Eggert]

------------------------------------------------------------
revno: 108423
fixes bug: http://debbugs.gnu.org/9642
author: Troels Nielsen <address@hidden>
committer: Paul Eggert <address@hidden>
branch nick: trunk
timestamp: Tue 2012-05-29 09:13:38 -0700
message:
  Do not avoid creating empty evaporating overlays (Bug#9642).
  
  * buffer.c (Fmove_overlay): Reinstate the earlier fix for
  Bug#9642, but explicitly check that the buffer the overlay would
  be moved to is live and rearrange lines to make sure that errors
  will not put the overlay in an inconsistent state.
  (Fdelete_overlay): Cosmetics.
modified:
  src/ChangeLog
  src/buffer.c

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2012-05-28 17:22:40 +0000
+++ b/src/ChangeLog     2012-05-29 16:13:38 +0000
@@ -1,3 +1,12 @@
+2012-05-29  Troels Nielsen  <address@hidden>
+
+       Do not avoid creating empty evaporating overlays (Bug#9642).
+       * buffer.c (Fmove_overlay): Reinstate the earlier fix for
+       Bug#9642, but explicitly check that the buffer the overlay would
+       be moved to is live and rearrange lines to make sure that errors
+       will not put the overlay in an inconsistent state.
+       (Fdelete_overlay): Cosmetics.
+
 2012-05-28  Eli Zaretskii  <address@hidden>
 
        * w32term.c (my_bring_window_to_top): New function.

=== modified file 'src/buffer.c'
--- a/src/buffer.c      2012-05-27 01:06:44 +0000
+++ b/src/buffer.c      2012-05-29 16:13:38 +0000
@@ -3676,10 +3676,10 @@
 buffer.  */)
   (Lisp_Object overlay, Lisp_Object beg, Lisp_Object end, Lisp_Object buffer)
 {
-  struct buffer *b, *ob;
+  struct buffer *b, *ob = 0;
   Lisp_Object obuffer;
   ptrdiff_t count = SPECPDL_INDEX ();
-  ptrdiff_t n_beg, n_end;
+  ptrdiff_t n_beg, n_end, o_beg IF_LINT (= 0), o_end IF_LINT (= 0);
 
   CHECK_OVERLAY (overlay);
   if (NILP (buffer))
@@ -3688,6 +3688,9 @@
     XSETBUFFER (buffer, current_buffer);
   CHECK_BUFFER (buffer);
 
+  if (NILP (Fbuffer_live_p (buffer)))
+    error ("Attempt to move overlay to a dead buffer");
+
   if (MARKERP (beg)
       && ! EQ (Fmarker_buffer (beg), buffer))
     error ("Marker points into wrong buffer");
@@ -3697,38 +3700,45 @@
 
   CHECK_NUMBER_COERCE_MARKER (beg);
   CHECK_NUMBER_COERCE_MARKER (end);
-  n_beg = clip_to_bounds (PTRDIFF_MIN, XINT (beg), PTRDIFF_MAX);
-  n_end = clip_to_bounds (PTRDIFF_MIN, XINT (end), PTRDIFF_MAX);
-
-  if (n_beg == n_end && ! NILP (Foverlay_get (overlay, Qevaporate)))
-    return Fdelete_overlay (overlay);
-
-  if (n_beg > n_end)
+
+  if (XINT (beg) > XINT (end))
     {
-      ptrdiff_t temp;
-      temp = n_beg; n_beg = n_end; n_end = temp;
+      Lisp_Object temp;
+      temp = beg; beg = end; end = temp;
     }
 
   specbind (Qinhibit_quit, Qt);
 
   obuffer = Fmarker_buffer (OVERLAY_START (overlay));
   b = XBUFFER (buffer);
-  ob = BUFFERP (obuffer) ? XBUFFER (obuffer) : (struct buffer *) 0;
+
+  if (!NILP (obuffer))
+    {
+      ob = XBUFFER (obuffer);
+
+      o_beg = OVERLAY_POSITION (OVERLAY_START (overlay));
+      o_end = OVERLAY_POSITION (OVERLAY_END (overlay));
+
+      ob->overlays_before =
+        unchain_overlay (ob->overlays_before, XOVERLAY (overlay));
+      ob->overlays_after =
+        unchain_overlay (ob->overlays_after, XOVERLAY (overlay));
+      eassert (XOVERLAY (overlay)->next == NULL);
+    }
+
+  /* Set the overlay boundaries, which may clip them.  */
+  Fset_marker (OVERLAY_START (overlay), beg, buffer);
+  Fset_marker (OVERLAY_END (overlay), end, buffer);
+
+  n_beg = marker_position (OVERLAY_START (overlay));
+  n_end = marker_position (OVERLAY_END (overlay));
 
   /* If the overlay has changed buffers, do a thorough redisplay.  */
   if (!EQ (buffer, obuffer))
     {
       /* Redisplay where the overlay was.  */
-      if (!NILP (obuffer))
-       {
-         ptrdiff_t o_beg;
-         ptrdiff_t o_end;
-
-         o_beg = OVERLAY_POSITION (OVERLAY_START (overlay));
-         o_end = OVERLAY_POSITION (OVERLAY_END (overlay));
-
-         modify_overlay (ob, o_beg, o_end);
-       }
+      if (ob)
+        modify_overlay (ob, o_beg, o_end);
 
       /* Redisplay where the overlay is going to be.  */
       modify_overlay (b, n_beg, n_end);
@@ -3736,11 +3746,6 @@
   else
     /* Redisplay the area the overlay has just left, or just enclosed.  */
     {
-      ptrdiff_t o_beg, o_end;
-
-      o_beg = OVERLAY_POSITION (OVERLAY_START (overlay));
-      o_end = OVERLAY_POSITION (OVERLAY_END (overlay));
-
       if (o_beg == n_beg)
        modify_overlay (b, o_end, n_end);
       else if (o_end == n_end)
@@ -3749,21 +3754,14 @@
        modify_overlay (b, min (o_beg, n_beg), max (o_end, n_end));
     }
 
-  if (!NILP (obuffer))
-    {
-      ob->overlays_before
-       = unchain_overlay (ob->overlays_before, XOVERLAY (overlay));
-      ob->overlays_after
-       = unchain_overlay (ob->overlays_after, XOVERLAY (overlay));
-      eassert (XOVERLAY (overlay)->next == NULL);
-    }
-
-  Fset_marker (OVERLAY_START (overlay), beg, buffer);
-  Fset_marker (OVERLAY_END   (overlay), end, buffer);
-
-  /* Put the overlay on the wrong list.  */
-  end = OVERLAY_END (overlay);
-  if (OVERLAY_POSITION (end) < b->overlay_center)
+  /* Delete the overlay if it is empty after clipping and has the
+     evaporate property.  */
+  if (n_beg == n_end && !NILP (Foverlay_get (overlay, Qevaporate)))
+    return unbind_to (count, Fdelete_overlay (overlay));
+
+  /* Put the overlay into the new buffer's overlay lists, first on the
+     wrong list.  */
+  if (n_end < b->overlay_center)
     {
       XOVERLAY (overlay)->next = b->overlays_after;
       b->overlays_after = XOVERLAY (overlay);
@@ -3797,9 +3795,12 @@
   b = XBUFFER (buffer);
   specbind (Qinhibit_quit, Qt);
 
-  b->overlays_before = unchain_overlay (b->overlays_before,XOVERLAY (overlay));
-  b->overlays_after  = unchain_overlay (b->overlays_after, XOVERLAY (overlay));
+  b->overlays_before
+    = unchain_overlay (b->overlays_before, XOVERLAY (overlay));
+  b->overlays_after
+    = unchain_overlay (b->overlays_after, XOVERLAY (overlay));
   eassert (XOVERLAY (overlay)->next == NULL);
+
   modify_overlay (b,
                  marker_position (OVERLAY_START (overlay)),
                  marker_position (OVERLAY_END   (overlay)));