# HG changeset patch
# User Gregory Szorc <gregory.szorc@gmail.com>
# Date 2018-02-12 00:56:29
# Node ID c02771617a70bb662a776306330ce4ef752f0718
# Parent  b587a889b97ead86dd3bb2125b47588d2d371779

py3: avoid changing dictionary during iteration

dict.items() and friends are iterators/views in Python 3. You
aren't allowed to mutate the underlying dictionary when iterating
on these views. So iterate over a copy of things.

Differential Revision: https://phab.mercurial-scm.org/D2164

diff --git a/mercurial/copies.py b/mercurial/copies.py
--- a/mercurial/copies.py
+++ b/mercurial/copies.py
@@ -123,7 +123,7 @@ def _chain(src, dst, a, b):
             t[k] = v
 
     # remove criss-crossed copies
-    for k, v in t.items():
+    for k, v in list(t.items()):
         if k in src and v in dst:
             del t[k]