diff --git a/hgext/narrow/narrowcommands.py b/hgext/narrow/narrowcommands.py
--- a/hgext/narrow/narrowcommands.py
+++ b/hgext/narrow/narrowcommands.py
@@ -433,7 +433,7 @@
 
     if update_working_copy:
         with repo.wlock(), repo.lock(), repo.transaction('narrow-wc') as tr:
-            narrowspec.updateworkingcopy(repo, tr)
+            narrowspec.updateworkingcopy(repo)
             narrowspec.copytoworkingcopy(repo, tr)
         return 0
 
diff --git a/mercurial/narrowspec.py b/mercurial/narrowspec.py
--- a/mercurial/narrowspec.py
+++ b/mercurial/narrowspec.py
@@ -266,7 +266,7 @@
         raise error.Abort(_("working copy's narrowspec is stale"),
                           hint=_("run 'hg tracked --update-working-copy'"))
 
-def updateworkingcopy(repo, tr):
+def updateworkingcopy(repo):
     oldspec = repo.vfs.tryread(DIRSTATE_FILENAME)
     newspec = repo.svfs.tryread(FILENAME)
 
@@ -294,5 +294,3 @@
     for f in newfiles:
         ds.normallookup(f)
     _writeaddedfiles(repo, pctx, newfiles)
-
-    ds.write(tr)