Re: [rant] Should reverting a buffer really discard undo history?

[Dan Nicolaescu <dann@ics.uci.edu>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

  > > Maybe other users have a different experience, but for me 99% of the
  > > time I would like undo info after a revert is when revert was invoked
  > > by VC/pcl-cvs after a commit.
  > > So from this users point of view if VC/pcl-cvs were not to revert the
  > > buffer, saving undo after revert would not be missed much. 
  > 
  > Indeed, it may also be useful to allow the revert-undoability to be
  > specified on a revert-by-revert basis.  And VC/PCL-CVS would be well served
  > by a "revert carefully" which would do something like "diff+patch" rather
  > than an actual revert.  Note that revert already does a limited form of
  > diff+patch since it checks the prefix&suffix of the file/buffer which hasn't
  > changed, so if only one line was changed the undo would record only
  > a one-line change rather than a complete delete+insert of the whole buffer.

If saving undo after revert is not implemented/accepted would it be
possible to avoid the revert if it is not needed after a commit? 
Wouldn't a (string= (md5 FILE) (md5 BUFFER)) be enough to avoid
reverting?