If you start a multifile commit from *vc-dir* and then change the
selected fileset, log-edit-done (C-c C-c) commits the original fileset
without comment.  The attached patch fixes this by recomputing the
fileset, and prompting the user if anything changed.  First, the user is
offered a chance to use the new fileset (since that is probably what was
intended), then to continue the commit with the original fileset.  If
both choices are refused, then the commit is aborted.  Most of the patch
factors vc-deduce-fileset-internal out of vc-deduce-fileset and
vc-filter-files-to-commit out of vc-next-action in order to avoid code
duplication.

   For symmetry, C-x v v ought to make the equivalent check when reusing
an existing log buffer.  It currently overwrites the changeset for any
commit in progress.  If that change is acceptable, I will submit a
separate patch.

   Along the way, I've also changed the name of the "observer" parameter
of vc-deduce-fileset to "nonviolent-p", and documented it as such, since
this seems to be what was intended:  This is passed non-nil only from
places that do not change VC state, such as vc-diff and vc-log.

					-- Bob Rogers
					   http://www.rgrjr.com/