diff --git a/mercurial/changelog.py b/mercurial/changelog.py
--- a/mercurial/changelog.py
+++ b/mercurial/changelog.py
@@ -570,7 +570,7 @@ class changelog(revlog.revlog):
         sortedfiles = sorted(files.touched)
         sidedata = None
         if self._copiesstorage == b'changeset-sidedata':
-            sidedata = metadata.encode_copies_sidedata(files)
+            sidedata = metadata.encode_files_sidedata(files)
 
         if extra:
             extra = encodeextra(extra)
diff --git a/mercurial/metadata.py b/mercurial/metadata.py
--- a/mercurial/metadata.py
+++ b/mercurial/metadata.py
@@ -318,7 +318,7 @@ def decodefileindices(files, data):
         return None
 
 
-def encode_copies_sidedata(files):
+def encode_files_sidedata(files):
     sortedfiles = sorted(files.touched)
     sidedata = {}
     p1copies = files.copied_from_p1