diff --git a/hgext/narrow/narrowbundle2.py b/hgext/narrow/narrowbundle2.py
--- a/hgext/narrow/narrowbundle2.py
+++ b/hgext/narrow/narrowbundle2.py
@@ -50,40 +50,6 @@
     caps[NARROWCAP] = ['v0']
     return caps
 
-def _packellipsischangegroup(repo, common, match, relevant_nodes,
-                             ellipsisroots, visitnodes, depth, source, version):
-    if version in ('01', '02'):
-        raise error.Abort(
-            'ellipsis nodes require at least cg3 on client and server, '
-            'but negotiated version %s' % version)
-    # We wrap cg1packer.revchunk, using a side channel to pass
-    # relevant_nodes into that area. Then if linknode isn't in the
-    # set, we know we have an ellipsis node and we should defer
-    # sending that node's data. We override close() to detect
-    # pending ellipsis nodes and flush them.
-    packer = changegroup.getbundler(version, repo,
-                                    filematcher=match)
-    # Give the packer the list of nodes which should not be
-    # ellipsis nodes. We store this rather than the set of nodes
-    # that should be an ellipsis because for very large histories
-    # we expect this to be significantly smaller.
-    packer.full_nodes = relevant_nodes
-    # Maps ellipsis revs to their roots at the changelog level.
-    packer.precomputed_ellipsis = ellipsisroots
-    # Maps CL revs to per-revlog revisions. Cleared in close() at
-    # the end of each group.
-    packer.clrev_to_localrev = {}
-    packer.next_clrev_to_localrev = {}
-    # Maps changelog nodes to changelog revs. Filled in once
-    # during changelog stage and then left unmodified.
-    packer.clnode_to_rev = {}
-    packer.changelog_done = False
-    # If true, informs the packer that it is serving shallow content and might
-    # need to pack file contents not introduced by the changes being packed.
-    packer.is_shallow = depth is not None
-
-    return packer.generate(common, visitnodes, False, source)
-
 # Serve a changegroup for a client with a narrow clone.
 def getbundlechangegrouppart_narrow(bundler, repo, source,
                                     bundlecaps=None, b2caps=None, heads=None,
@@ -150,7 +116,7 @@
         newvisit, newfull, newellipsis = exchange._computeellipsis(
             repo, set(), common, known, newmatch)
         if newvisit:
-            cg = _packellipsischangegroup(
+            cg = changegroup._packellipsischangegroup(
                 repo, common, newmatch, newfull, newellipsis,
                 newvisit, depth, source, version)
             part = bundler.newpart('changegroup', data=cg)
@@ -163,7 +129,7 @@
 
     repo.ui.debug('Found %d relevant revs\n' % len(relevant_nodes))
     if visitnodes:
-        cg = _packellipsischangegroup(
+        cg = changegroup._packellipsischangegroup(
             repo, common, newmatch, relevant_nodes, ellipsisroots,
             visitnodes, depth, source, version)
         part = bundler.newpart('changegroup', data=cg)
diff --git a/mercurial/changegroup.py b/mercurial/changegroup.py
--- a/mercurial/changegroup.py
+++ b/mercurial/changegroup.py
@@ -1055,3 +1055,36 @@
                     (f, hex(n)))
 
     return revisions, files
+
+def _packellipsischangegroup(repo, common, match, relevant_nodes,
+                             ellipsisroots, visitnodes, depth, source, version):
+    if version in ('01', '02'):
+        raise error.Abort(
+            'ellipsis nodes require at least cg3 on client and server, '
+            'but negotiated version %s' % version)
+    # We wrap cg1packer.revchunk, using a side channel to pass
+    # relevant_nodes into that area. Then if linknode isn't in the
+    # set, we know we have an ellipsis node and we should defer
+    # sending that node's data. We override close() to detect
+    # pending ellipsis nodes and flush them.
+    packer = getbundler(version, repo, filematcher=match)
+    # Give the packer the list of nodes which should not be
+    # ellipsis nodes. We store this rather than the set of nodes
+    # that should be an ellipsis because for very large histories
+    # we expect this to be significantly smaller.
+    packer.full_nodes = relevant_nodes
+    # Maps ellipsis revs to their roots at the changelog level.
+    packer.precomputed_ellipsis = ellipsisroots
+    # Maps CL revs to per-revlog revisions. Cleared in close() at
+    # the end of each group.
+    packer.clrev_to_localrev = {}
+    packer.next_clrev_to_localrev = {}
+    # Maps changelog nodes to changelog revs. Filled in once
+    # during changelog stage and then left unmodified.
+    packer.clnode_to_rev = {}
+    packer.changelog_done = False
+    # If true, informs the packer that it is serving shallow content and might
+    # need to pack file contents not introduced by the changes being packed.
+    packer.is_shallow = depth is not None
+
+    return packer.generate(common, visitnodes, False, source)