diff --git a/mercurial/copies.py b/mercurial/copies.py
--- a/mercurial/copies.py
+++ b/mercurial/copies.py
@@ -134,7 +134,7 @@
             if t[v] != k:
                 # file wasn't renamed back to itself (i.e. case 4, not 3)
                 t[k] = t[v]
-        if v in src:
+        elif v in src:
             # file is a copy of an existing file, i.e. case 6.
             t[k] = v