Re: pending-undo-list is not buffer local

[Richard Stallman]

    Various parts of Emacs manipulate `buffer-undo-list' in various ways.
    `revert-buffer' may reset it.  Some applications temporarily bind it to
    t to avoid, for example, recording text property changes.  Finally undo
    recording may be switched off.  Should `pending-undo-list' be affected
    by all these and how?

We have no need to worry about this now.
If and when someone implements a more powerful undo facility,
we will see what kind of support it needs.