# HG changeset patch
# User Martijn Pieters <mjpieters@fb.com>
# Date 1489348572 25200
# Node ID d30fb3de4b403209b09c14e4ccaee5fb80accbbf
# Parent  7548522742b5f4f9f5c0881ae4a2783ecda2f969
config: avoid using a mutable default

Nothing *currently* mutates this list, but the moment something does it'll be
shared between all config instances. Avoid this eventuality.

diff -r 7548522742b5 -r d30fb3de4b40 mercurial/config.py
--- a/mercurial/config.py	Fri Aug 05 14:09:04 2016 +0200
+++ b/mercurial/config.py	Sun Mar 12 12:56:12 2017 -0700
@@ -18,11 +18,11 @@
 )
 
 class config(object):
-    def __init__(self, data=None, includepaths=[]):
+    def __init__(self, data=None, includepaths=None):
         self._data = {}
         self._source = {}
         self._unset = []
-        self._includepaths = includepaths
+        self._includepaths = includepaths or []
         if data:
             for k in data._data:
                 self._data[k] = data[k].copy()