diff --git a/hgext/patchbomb.py b/hgext/patchbomb.py
--- a/hgext/patchbomb.py
+++ b/hgext/patchbomb.py
@@ -213,8 +213,8 @@ def _formatflags(ui, repo, rev, flags):
     if not tmpl:
         return b' '.join(flags)
     out = util.stringio()
-    opts = {b'template': templater.unquotestring(tmpl)}
-    with formatter.templateformatter(ui, out, b'patchbombflag', opts) as fm:
+    spec = formatter.templatespec(b'', templater.unquotestring(tmpl), None)
+    with formatter.templateformatter(ui, out, b'patchbombflag', {}, spec) as fm:
         fm.startitem()
         fm.context(ctx=repo[rev])
         fm.write(b'flags', b'%s', fm.formatlist(flags, name=b'flag'))
diff --git a/mercurial/formatter.py b/mercurial/formatter.py
--- a/mercurial/formatter.py
+++ b/mercurial/formatter.py
@@ -475,10 +475,9 @@ class _templateconverter(object):
 
 
 class templateformatter(baseformatter):
-    def __init__(self, ui, out, topic, opts):
+    def __init__(self, ui, out, topic, opts, spec):
         baseformatter.__init__(self, ui, topic, opts, _templateconverter)
         self._out = out
-        spec = lookuptemplate(ui, topic, opts.get(b'template', b''))
         self._tref = spec.ref
         self._t = loadtemplater(
             ui,
@@ -723,7 +722,8 @@ def formatter(ui, out, topic, opts):
     elif template == b"debug":
         return debugformatter(ui, out, topic, opts)
     elif template != b"":
-        return templateformatter(ui, out, topic, opts)
+        spec = lookuptemplate(ui, topic, opts.get(b'template', b''))
+        return templateformatter(ui, out, topic, opts, spec)
     # developer config: ui.formatdebug
     elif ui.configbool(b'ui', b'formatdebug'):
         return debugformatter(ui, out, topic, opts)