diff --git a/mercurial/templatekw.py b/mercurial/templatekw.py
--- a/mercurial/templatekw.py
+++ b/mercurial/templatekw.py
@@ -355,6 +355,9 @@ def showchangessincelatesttag(repo, ctx,
 def showmanifest(**args):
     repo, ctx, templ = args['repo'], args['ctx'], args['templ']
     mnode = ctx.manifestnode()
+    if mnode is None:
+        # just avoid crash, we might want to use the 'ff...' hash in future
+        return
     args = args.copy()
     args.update({'rev': repo.manifest.rev(mnode), 'node': hex(mnode)})
     return templ('manifest', **args)
diff --git a/tests/test-command-template.t b/tests/test-command-template.t
--- a/tests/test-command-template.t
+++ b/tests/test-command-template.t
@@ -51,6 +51,12 @@ Second branch starting at nullrev:
   8 t
   7 f
 
+Some keywords are invalid for working-directory revision, but they should
+never cause crash:
+
+  $ hg log -r 'wdir()' -T '{manifest}\n'
+  
+
 Quoting for ui.logtemplate
 
   $ hg tip --config "ui.logtemplate={rev}\n"