Re: RCS, again: another removed functionality: undo last-checkin

[Stefan Monnier]

> Maybe we should have both "rollback" and "revert" commands.  Multiple
> backends seem to distinguish them already.

They are indeed very different, so it makes a lot of sense to have them
as completely separate commands.

The "revert" (which IIUC just installs a new change which undoes the
effect of some earlier change) can mostly be implemented in
a backend-independent way.

But the "rollback" (which IIUC can destructively remove an previous
existing commit, I guess I'd call it "uncommit") is a lot more
problematic, since various backends support it in very different ways
with very different limitations.  Generalizing the "Amend:" support of
vc-git.el to other backends would probably cover 99% of the use cases.

If you feel it's really important that user be able to delete a revision
from within Emacs, why not provide a vc-rcs-delete-commits command in
vc-rcs.el?  That would be a lot simpler to implement and wouldn't force us
to come up with some weird pseudo-generic functionality that might end
up not even supporting 100% of RCS's use cases.


        Stefan