timers and undo

[Luc Teirlinck]

The way timers treat undo is really peculiar.

Do `emacs -q'.  Then:

M-: (run-at-time 5 5 (lambda () (with-current-buffer "*scratch*"
(insert "aaaaaaa\n"))))

Wait till enough lines are inserted.  C-/.  The entire block of
inserted lines gets deleted all at once.  This apparently causes
problems with undo-outer-limit as I pointed out before.

But there is more.

Wait until once more a bunch of lines are inserted.  I now expected
that C-/ would get rid of these inserted lines once more.  But no.
It deletes the introductory comment lines.  The "aaaaaaa" lines
stay and they are impossible to undo after repaeting C-/

undo-more: No further undo information

It seems hard to consider this a deliberate "feature".

Sincerely,

Luc.