Do not avoid creating empty evaporating overlays (Bug#9642).

* buffer.c (Fmove_overlay): Revert the change of 2012-04-23.
That is, do not delete an evaporating overlay if it becomes
empty after its bounds are adjusted to fit within its buffer.
This fix caused other problems, and I'm reverting it until we get
to the bottom of them.

diff --git a/src/ChangeLog b/src/ChangeLog
index 55caf3c..6cef4f6 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2012-04-28  Paul Eggert  <eggert@cs.ucla.edu>
+
+       Do not avoid creating empty evaporating overlays (Bug#9642).
+       * buffer.c (Fmove_overlay): Revert the change of 2012-04-23.
+       That is, do not delete an evaporating overlay if it becomes
+       empty after its bounds are adjusted to fit within its buffer.
+       This fix caused other problems, and I'm reverting it until we get
+       to the bottom of them.
+
 2012-04-27  Chong Yidong  <cyd@gnu.org>
 
        * xselect.c (x_convert_selection): Initialize a pointer (Bug#11315).

diff --git a/src/buffer.c b/src/buffer.c
index 6c2e21c..9bac3ec 100644 (file)
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -3682,7 +3682,6 @@ buffer.  */)
   struct buffer *b, *ob;
   Lisp_Object obuffer;
   int count = SPECPDL_INDEX ();
-  ptrdiff_t n_beg, n_end;
 
   CHECK_OVERLAY (overlay);
   if (NILP (buffer))
@@ -3701,23 +3700,15 @@ buffer.  */)
   CHECK_NUMBER_COERCE_MARKER (beg);
   CHECK_NUMBER_COERCE_MARKER (end);
 
+  if (XINT (beg) == XINT (end) && ! NILP (Foverlay_get (overlay, Qevaporate)))
+    return Fdelete_overlay (overlay);
+
   if (XINT (beg) > XINT (end))
     {
       Lisp_Object temp;
       temp = beg; beg = end; end = temp;
     }
 
-  /* First 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));
-
-  /* Now, 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 Fdelete_overlay (overlay);
-
   specbind (Qinhibit_quit, Qt);
 
   obuffer = Fmarker_buffer (OVERLAY_START (overlay));
@@ -3740,7 +3731,7 @@ buffer.  */)
        }
 
       /* Redisplay where the overlay is going to be.  */
-      modify_overlay (b, n_beg, n_end);
+      modify_overlay (b, XINT (beg), XINT (end));
     }
   else
     /* Redisplay the area the overlay has just left, or just enclosed.  */
@@ -3750,12 +3741,16 @@ buffer.  */)
       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)
-       modify_overlay (b, o_beg, n_beg);
+      if (o_beg == XINT (beg))
+       modify_overlay (b, o_end, XINT (end));
+      else if (o_end == XINT (end))
+       modify_overlay (b, o_beg, XINT (beg));
       else
-       modify_overlay (b, min (o_beg, n_beg), max (o_end, n_end));
+       {
+         if (XINT (beg) < o_beg) o_beg = XINT (beg);
+         if (XINT (end) > o_end) o_end = XINT (end);
+         modify_overlay (b, o_beg, o_end);
+       }
     }
 
   if (!NILP (obuffer))
@@ -3767,8 +3762,12 @@ buffer.  */)
       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.  */
-  if (n_end < b->overlay_center)
+  end = OVERLAY_END (overlay);
+  if (OVERLAY_POSITION (end) < b->overlay_center)
     {
       XOVERLAY (overlay)->next = b->overlays_after;
       b->overlays_after = XOVERLAY (overlay);