Re: 4 minor suggestions for files.el

[Richard Stallman]

    VC does a revert-buffer after each version control operation, so that
    changes in version headers are picked up.

    If I understand correctly, the revert-buffer would be undoable.

I think that is what he is proposing.

I think that is a misguided feature.  It is not right to undo
the revert-buffer unless you can undo the whole VC operation with it.
But that, if we can implement it, must be a VC operation;
M-x undo should not be able to do it.

I think that the correct way for check-in and update to interact with
M-x undo is to transpose the old undo list somehow to the buffer as it
has been updated.

If I edit the buffer and then do an RCS check-in, and the check-in
updates an RCS header in the file, and then I undo, this should not
undo the change in the RCS header.  Rather, it should undo the change
that I made manually before the check-in.

Likewise, if I edit the buffer and then do a CVS update, I should
then be able to undo the edit I made, but not the changes made by
the CVS update.

Implementing this is nontrivial, but not impossible.

The revert-buffer should never be undone without (say