revert: add -n/--dry-run option

mercurial/commands.py

@@ -2417,6 +2417,7 b' def revert(ui, repo, *pats, **opts):'
                 bakname = "%s.orig" % rel
                 ui.note(_('saving current version of %s as %s\n') %
                         (rel, bakname))
+                if not opts.get('dry_run'):
                 shutil.copyfile(rel, bakname)
                 shutil.copymode(rel, bakname)
             if ui.verbose or not exact:
@@ -2449,6 +2450,7 b' def revert(ui, repo, *pats, **opts):'
                 else:
                     handle(remove, False)
 
+    if not opts.get('dry_run'):
     repo.dirstate.forget(forget[0])
     r = repo.update(node, False, True, update.has_key, False, wlock=wlock,
                     show_stats=False)
@@ -3075,7 +3077,8 b' table = {'
          [('r', 'rev', '', _('revision to revert to')),
           ('', 'no-backup', None, _('do not save backup copies of files')),
           ('I', 'include', [], _('include names matching given patterns')),
-          ('X', 'exclude', [], _('exclude names matching given patterns'))],
+          ('X', 'exclude', [], _('exclude names matching given patterns')),
+          ('n', 'dry-run', None, _('print what would be done'))],
          _('hg revert [-r REV] [NAME]...')),
     "rollback": (rollback, [], _('hg rollback')),
     "root": (root, [], _('hg root')),