--- a/hgext3rd/topic/__init__.py	Wed Jun 21 13:21:08 2017 +0200
+++ b/hgext3rd/topic/__init__.py	Wed Jun 21 13:18:47 2017 +0200
@@ -62,6 +62,7 @@
     context,
     error,
     extensions,
+    hg,
     localrepo,
     lock,
     merge,
@@ -306,8 +307,9 @@
 def _changetopics(ui, repo, revset, newtopic):
     rewrote = 0
     needevolve = False
-    l = txn = None
+    wl = l = txn = None
     try:
+        wl = repo.wlock()
         l = repo.lock()
         txn = repo.transaction('rewrite-topics')
         p1 = None
@@ -358,9 +360,19 @@
             needevolve = needevolve or (len(c.children()) > 0)
             obsolete.createmarkers(repo, [(c, (repo[newnode],))])
             rewrote += 1
+        # move the working copy too
+        wctx = repo[None]
+        # in-progress merge is a bit too complexe for now.
+        if len(wctx.parents()) == 1:
+            newid = successors.get(wctx.p1().node())
+            if newid is not None:
+                # this provide some useless output we shoudl eventually suppress
+                #
+                # 0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+                hg.update(repo, newid)
         txn.close()
     finally:
-        lock.release(txn, l)
+        lock.release(txn, l, wl)
         repo.invalidate()
     ui.status('changed topic on %d changes\n' % rewrote)
     if needevolve: