From patchwork Sat Oct 10 08:47:24 2020
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Subject: [3, of,
 3] revlog: prevent recreating a tuple again and again for each rev
From: Pulkit Goyal <7895pulkit@gmail.com>
X-Patchwork-Id: 47435
Message-Id: <a96cd3eebf8eba04a351.1602319644@workspace>
To: mercurial-devel@mercurial-scm.org
Date: Sat, 10 Oct 2020 14:17:24 +0530

# HG changeset patch
# User Pulkit Goyal <7895pulkit@gmail.com>
# Date 1602252446 -19800
#      Fri Oct 09 19:37:26 2020 +0530
# Node ID a96cd3eebf8eba04a351615728c9635e8941af10
# Parent  911cea33820c98da3fa2e4891153e674600df1af
# EXP-Topic sidedata-upgrade
revlog: prevent recreating a tuple again and again for each rev

I am tracking a memory leak during upgrade which does revlog cloning. Although
this does not make much of difference but seemed like a nice change to me.

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -2773,6 +2773,7 @@ class revlog(object):
         sidedatachanges = sidedatacompanion is not None
         deltacomputer = deltautil.deltacomputer(destrevlog)
         index = self.index
+        defsidedataactions = (False, (), {})
         for rev in self:
             entry = index[rev]
 
@@ -2784,9 +2785,10 @@ class revlog(object):
             p2 = index[entry[6]][7]
             node = entry[7]
 
-            sidedataactions = (False, [], {})
             if sidedatachanges:
                 sidedataactions = sidedatacompanion(self, rev)
+            else:
+                sidedataactions = defsidedataactions
 
             # (Possibly) reuse the delta from the revlog if allowed and
             # the revlog chunk is a delta.