diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -1492,9 +1492,9 @@ class changeset_templater(changeset_prin
             self.t = templater.templater.frommapfile(mapfile, filters=filters,
                                                      cache=defaulttempl)
         else:
-            self.t = templater.templater(filters=filters, cache=defaulttempl)
-            if tmpl:
-                self.t.cache['changeset'] = tmpl
+            self.t = formatter.maketemplater(ui, 'changeset', tmpl,
+                                             filters=filters,
+                                             cache=defaulttempl)
 
         self.cache = {}
 
diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -46,6 +46,7 @@ from . import (
     exchange,
     extensions,
     fileset,
+    formatter,
     graphmod,
     hbisect,
     help,
@@ -3681,8 +3682,7 @@ def debugtemplate(ui, repo, tmpl, **opts
     mapfile = None
     if revs is None:
         k = 'debugtemplate'
-        t = templater.templater()
-        t.cache[k] = tmpl
+        t = formatter.maketemplater(ui, k, tmpl)
         ui.write(templater.stringify(t(k, **props)))
     else:
         displayer = cmdutil.changeset_templater(ui, repo, None, opts, tmpl,
diff --git a/mercurial/filemerge.py b/mercurial/filemerge.py
--- a/mercurial/filemerge.py
+++ b/mercurial/filemerge.py
@@ -17,6 +17,7 @@ from .node import nullid, short
 
 from . import (
     error,
+    formatter,
     match,
     scmutil,
     simplemerge,
@@ -526,7 +527,7 @@ def _formatlabels(repo, fcd, fco, fca, l
 
     ui = repo.ui
     template = ui.config('ui', 'mergemarkertemplate', _defaultconflictmarker)
-    tmpl = templater.templater(cache={'conflictmarker': template})
+    tmpl = formatter.maketemplater(ui, 'conflictmarker', template)
 
     pad = max(len(l) for l in labels)
 
diff --git a/mercurial/formatter.py b/mercurial/formatter.py
--- a/mercurial/formatter.py
+++ b/mercurial/formatter.py
@@ -193,7 +193,11 @@ def gettemplater(ui, topic, spec):
     assert not (tmpl and mapfile)
     if mapfile:
         return templater.templater.frommapfile(mapfile)
-    t = templater.templater()
+    return maketemplater(ui, topic, tmpl)
+
+def maketemplater(ui, topic, tmpl, filters=None, cache=None):
+    """Create a templater from a string template 'tmpl'"""
+    t = templater.templater(filters=filters, cache=cache)
     if tmpl:
         t.cache[topic] = tmpl
     return t