From patchwork Wed Sep 17 16:36:34 2014
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: revset: document the choice made in _generatorset.__iter__
From: Pierre-Yves David <pierre-yves.david@ens-lyon.org>
X-Patchwork-Id: 5851
Message-Id: <e282c07bac1a5627920f.1410971794@marginatus.alto.octopoid.net>
To: mercurial-devel@selenic.com
Cc: Pierre-Yves David <pierre-yves.david@ens-lyon.org>
Date: Wed, 17 Sep 2014 09:36:34 -0700

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@fb.com>
# Date 1410936161 25200
#      Tue Sep 16 23:42:41 2014 -0700
# Node ID e282c07bac1a5627920f53bd8b233a55ce42d05d
# Parent  a476ee0b8e799c1b9b82ad2db350c90a31274879
revset: document the choice made in _generatorset.__iter__

The method code looks a bit ugly but have good reason to do so. We document them
to prevent naive refactoring in the future.

diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -2646,10 +2646,16 @@ class _generatorset(object):
         if self._finished:
             for x in self._genlist:
                 yield x
             return
 
+        # we have to use this complexe iteration strategy to allow multiple
+        # iteration at the same time. We need to be able to catch revision
+        # removed from `consumegen` and added to genlist in another instance.
+        #
+        # Getting ride of it would provide an about 15% speed up on this
+        # iteration.
         i = 0
         genlist = self._genlist
         consume = self._consumegen()
         while True:
             if i < len(genlist):