# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@ens-lyon.org>
# Date 2017-03-15 22:05:54
# Node ID 6e1c79578e5cb619b838f0f4683dbed1cb65d4a9
# Parent  406705701c2d77a527794d40068278d07bec877a

mq: explicitly tests for None

Changeset fd3d8eb7f545 removed the mutable default value, but did not explicitly
tested for None. Such implicit testing can introduce semantic and performance
issue. We move to an explicit testing for None as recommended by PEP8:

https://www.python.org/dev/peps/pep-0008/#programming-recommendations

diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -722,7 +722,8 @@ class queue(object):
 
     def printdiff(self, repo, diffopts, node1, node2=None, files=None,
                   fp=None, changes=None, opts=None):
-        opts = opts or {}
+        if opts is None:
+            opts = {}
         stat = opts.get('stat')
         m = scmutil.match(repo[node1], files, opts)
         cmdutil.diffordiffstat(self.ui, repo, diffopts, node1, node2,  m,