# HG changeset patch
# User Pulkit Goyal <pulkit@yandex-team.ru>
# Date 2019-03-31 13:27:10
# Node ID f0def07fa82fb436e493a1beddfeb351ed9e4822
# Parent  29c22496dd973a568caae2953866b3d24eae3d6f

branchmap: implement __contains__()

We have good occurences of `if branch in branchmap()` in our code. If
__contains__() is not implemented then it will use __iter__() to find whether
the element exists or not which is not good.

I am bit confused that whether I should move existing callers to hasbranch() or
this patch is a good way.

Differential Revision: https://phab.mercurial-scm.org/D6206

diff --git a/mercurial/branchmap.py b/mercurial/branchmap.py
--- a/mercurial/branchmap.py
+++ b/mercurial/branchmap.py
@@ -182,6 +182,9 @@ class branchcache(object):
     def __getitem__(self, key):
         return self._entries[key]
 
+    def __contains__(self, key):
+        return key in self._entries
+
     def iteritems(self):
         return self._entries.iteritems()