diff -r 0b5716ec8500 -r 3da4bd50103d mercurial/cmdutil.py
--- a/mercurial/cmdutil.py	Tue Nov 28 11:00:54 2017 -0500
+++ b/mercurial/cmdutil.py	Wed Nov 29 07:57:17 2017 +0530
@@ -3445,6 +3445,7 @@
     return repo.status(match=scmutil.match(repo[None], pats, opts))
 
 def revert(ui, repo, ctx, parents, *pats, **opts):
+    opts = pycompat.byteskwargs(opts)
     parent, p2 = parents
     node = ctx.node()
 
@@ -3722,7 +3723,8 @@
             # Revert the subrepos on the revert list
             for sub in targetsubs:
                 try:
-                    wctx.sub(sub).revert(ctx.substate[sub], *pats, **opts)
+                    wctx.sub(sub).revert(ctx.substate[sub], *pats,
+                                         **pycompat.strkwargs(opts))
                 except KeyError:
                     raise error.Abort("subrepository '%s' does not exist in %s!"
                                       % (sub, short(ctx.node())))