Re: undo after repeatedly calling 'repeat' leaves cursor in the wrong place

[martin rudalics <rudalics@gmx.at>]

 > Type
 >   "x C-x z z z z C-x u"
 > (to insert an 'x', repeat the insert 4 times, then undo the last of the 4)
 >
 > Before the "C-x u" there were 5 'x's with the cursor after them all.
 > After the "C-x u" there are 4 'x's, as expected, but the cursor is on
 > the 2nd one, whereas I would expect it to be after the 4th one.
 >
 > If "C-x z" is used in full each time, instead of just hitting 'z' over
 > and over, then the undo works as expected.

`repeat' has the loop

         (while (eq (read-event) repeat-repeat-char)
	  ;; Make each repetition undo separately.
	  (undo-boundary)
           (repeat repeat-arg))

Note that `read-event' does not update `last_point_position' and
`undo-boundary' inserts nil into `buffer-undo-list' which prevents
combining the insertions.  `record_insert' calls `record_point' with the
positions where an "x" shall be inserted (2, 3, ...) but `record_point'
still relies on the old position (namely 2) stored for
`last_point_position', decides that it is not equal to point in

       if (last_point_position != pt)
	current_buffer->undo_list
	  = Fcons (make_number (last_point_position), current_buffer->undo_list);

and repeatedly inserts a 2 into `buffer-undo-list'.  Note that
replacing the latter by

       if (last_point_position != pt)
	{
	  current_buffer->undo_list
	    = Fcons (make_number (last_point_position), current_buffer->undo_list);
	  last_point_position = pt;
	}

still gets an off-by-one error.  I think two changes are needed:

(1) For a self-insert-command `repeat' should not construct undo
boundaries.  This would correct the bug reported by Chris but fail for
more complex commands.

(2) Use a separate variable, locally bound in `repeat' around the
recursive call to itself, to assert that `record_point' updates
`last_point_position' before comparing it with `pt'.  Maybe someone has
an idea how to avoid such a variable.  I'd rather not remove such items
from `buffer-undo-list' manually.