[PATCH "] revlog: preserve `_lazydelta` attribute in `revlog.clone`

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at octobus.net>
# Date 1551710814 -3600
#      Mon Mar 04 15:46:54 2019 +0100
# Node ID bbe72376f2a91b383370619b3a0f66cf4a5d8178
# Parent  82d9728ace9535057d77df6c920385861ec00072
# EXP-Topic lazydelta
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r bbe72376f2a9
revlog: preserve `_lazydelta` attribute in `revlog.clone`

The attribute was introduce in 688fc33e105d, Yuya Nishihara pointed out that
this preservation was missing. This should be fixed by this changesets.

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -2396,7 +2396,9 @@ class revlog(object):
         if getattr(destrevlog, 'filteredrevs', None):
             raise ValueError(_('destination revlog has filtered revisions'))
 
-        # lazydeltabase controls whether to reuse a cached delta, if possible.
+        # lazydelta and lazydeltabase controls whether to reuse a cached delta,
+        # if possible.
+        oldlazydelta = destrevlog._lazydelta
         oldlazydeltabase = destrevlog._lazydeltabase
         oldamd = destrevlog._deltabothparents
 
@@ -2460,6 +2462,7 @@ class revlog(object):
                 if addrevisioncb:
                     addrevisioncb(self, rev, node)
         finally:
+            destrevlog._lazydelta = oldlazydelta
             destrevlog._lazydeltabase = oldlazydeltabase
             destrevlog._deltabothparents = oldamd