--- a/hgext/transplant.py
+++ b/hgext/transplant.py
@@ -575,6 +575,7 @@ def transplant(ui, repo, *revs, **opts):
         tp.apply(repo, source, revmap, merges, opts)
     finally:
         if bundle:
+            source.close()
             os.unlink(bundle)
 
 cmdtable = {