Re: buffer-undo-list

[Stefan Monnier <monnier@iro.umontreal.ca>]

>>>>> "Johan" == Johan Bockgård <bojohan> writes:

> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>>> When I move the undo_list to before name and redo the experiment, I hit
>>> the breakpoint many many times.
>> 
>>> So either the special undo_list handling code should be removed or the
>>> undo_list moved before name in buffer.h.
>> 
>> Agreed.  The field was moved by Richard on 14-Oct-2002 but the change
>> log doesn't say why this was done, so I just undid it.

> But now

>   (assq 'buffer-undo-list (buffer-local-variables))
>     => nil

>   (buffer-local-value 'buffer-undo-list (get-buffer "*scratch*"))
>     => nil (global value)

I installed the patch below which should fix these problems.


        Stefan


Index: src/buffer.c
===================================================================
RCS file: /sources/emacs/emacs/src/buffer.c,v
retrieving revision 1.550
diff -u -r1.550 buffer.c
--- src/buffer.c	10 Feb 2008 02:14:00 -0000	1.550
+++ src/buffer.c	11 Feb 2008 17:54:48 -0000
@@ -496,7 +496,9 @@
 
   XSETBUFFER (to_buffer, to);
 
-  for (offset = PER_BUFFER_VAR_OFFSET (name) + sizeof (Lisp_Object);
+  /* buffer-local Lisp variables start at `undo_list',
+     tho only the ones from `name' on are GC'd normally.  */
+  for (offset = PER_BUFFER_VAR_OFFSET (undo_list) + sizeof (Lisp_Object);
        offset < sizeof *to;
        offset += sizeof (Lisp_Object))
     {
@@ -808,7 +810,9 @@
   /* For each slot that has a default value,
      copy that into the slot.  */
 
-  for (offset = PER_BUFFER_VAR_OFFSET (name);
+  /* buffer-local Lisp variables start at `undo_list',
+     tho only the ones from `name' on are GC'd normally.  */
+  for (offset = PER_BUFFER_VAR_OFFSET (undo_list);
        offset < sizeof *b;
        offset += sizeof (Lisp_Object))
     {
@@ -940,7 +944,9 @@
       int found = 0;
 
       /* Look in special slots */
-      for (offset = PER_BUFFER_VAR_OFFSET (name);
+      /* buffer-local Lisp variables start at `undo_list',
+	 tho only the ones from `name' on are GC'd normally.  */
+      for (offset = PER_BUFFER_VAR_OFFSET (undo_list);
 	   offset < sizeof (struct buffer);
 	   /* sizeof EMACS_INT == sizeof Lisp_Object */
 	   offset += (sizeof (EMACS_INT)))
@@ -1051,7 +1057,9 @@
   {
     int offset, idx;
 
-    for (offset = PER_BUFFER_VAR_OFFSET (name);
+    /* buffer-local Lisp variables start at `undo_list',
+       tho only the ones from `name' on are GC'd normally.  */
+    for (offset = PER_BUFFER_VAR_OFFSET (undo_list);
 	 offset < sizeof (struct buffer);
 	 /* sizeof EMACS_INT == sizeof Lisp_Object */
 	 offset += (sizeof (EMACS_INT)))