--- a/mercurial/revlogutils/nodemap.py	Mon Feb 15 15:13:20 2021 +0530
+++ b/mercurial/revlogutils/nodemap.py	Wed Feb 10 17:08:34 2021 +0530
@@ -128,6 +128,14 @@
         notr._postclose[k](None)
 
 
+def delete_nodemap(tr, repo, revlog):
+    """ Delete nodemap data on disk for a given revlog"""
+    if revlog.nodemap_file is None:
+        msg = "calling persist nodemap on a revlog without the feature enabled"
+        raise error.ProgrammingError(msg)
+    repo.svfs.unlink(revlog.nodemap_file)
+
+
 def persist_nodemap(tr, revlog, pending=False, force=False):
     """Write nodemap data on disk for a given revlog"""
     if getattr(revlog, 'filteredrevs', ()):