# HG changeset patch
# User Pierre-Yves David <pierre-yves.da...@octobus.net>
# Date 1551267618 -3600
# Wed Feb 27 12:40:18 2019 +0100
# Node ID d1df36a5e877119ca96134b0ee2e886c32f40c38
# Parent ed7aebbee814840433cf40ce02aecde83d6129c1
# EXP-Topic delta-control
# Available At https://bitbucket.org/octobus/mercurial-devel/
# hg pull https://bitbucket.org/octobus/mercurial-devel/ -r
d1df36a5e877
storage: introduce a `revlog.reuse-external-delta` config
This option goes a bit further and provides a way to get the same behavior as
the
`re-delta-all` optimisation from `hg debugupgraderepo`.
The effect of the option is a bit hard to test as we do not have multiple diff
algorithm at hand. However, we at least make sure the code path run.
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -983,6 +983,9 @@ coreconfigitem('storage', 'revlog.optimi
default=True,
alias=[('format', 'aggressivemergedeltas')],
)
+coreconfigitem('storage', 'revlog.reuse-external-delta',
+ default=True,
+)
coreconfigitem('storage', 'revlog.reuse-external-delta-parent',
default=None,
)
diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
--- a/mercurial/help/config.txt
+++ b/mercurial/help/config.txt
@@ -1865,6 +1865,22 @@ category impact performance and reposito
considered. Even when disabled, the existing delta from the source will be
reused if the same delta parent is selected.
+``revlog.reuse-external-delta``
+ Control the reuse of delta from external source.
+ (typically: apply bundle from `hg pull` or `hg push`).
+
+ New revisions are usually provided as a delta against another revision. By
+ default, Mercurial will not recompute the same delta again , trusting
+ externally provided deltas. There have been rare cases of small adjustement
+ to the diffing algorithm in the past. So in some rare case, recomputing
+ delta provided by ancient clients can provides better results. Disabling
+ this option means going through a full delta recomputation for all incoming
+ revisions. It means a large increase in CPU usage and will slow operations
+ down.
+
+ This option is enabled by default. When disabled, it also disable the
+ related ``storage.revlog.reuse-external-delta-parent`` option.
+
``server``
----------
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -753,10 +753,14 @@ def resolverevlogstorevfsoptions(ui, req
options[b'deltabothparents'] = deltabothparents
- lazydeltabase = ui.configbool(b'storage',
- b'revlog.reuse-external-delta-parent')
+ lazydelta = ui.configbool(b'storage', b'revlog.reuse-external-delta')
+ lazydeltabase = False
+ if lazydelta:
+ lazydeltabase = ui.configbool(b'storage',
+ b'revlog.reuse-external-delta-parent')
if lazydeltabase is None:
lazydeltabase = not scmutil.gddeltaconfig(ui)
+ options[b'lazydelta'] = lazydelta
options[b'lazydeltabase'] = lazydeltabase
chainspan = ui.configbytes(b'experimental', b'maxdeltachainspan')
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -410,7 +410,10 @@ class revlog(object):
self._maxchainlen = opts['maxchainlen']
if 'deltabothparents' in opts:
self._deltabothparents = opts['deltabothparents']
- self._lazydeltabase = bool(opts.get('lazydeltabase', False))
+ self._lazydelta = bool(opts.get('lazydelta', True))
+ self._lazydeltabase = False
+ if self._lazydelta:
+ self._lazydeltabase = bool(opts.get('lazydeltabase', False))
if 'compengine' in opts:
self._compengine = opts['compengine']
if 'maxdeltachainspan' in opts:
diff --git a/mercurial/revlogutils/deltas.py b/mercurial/revlogutils/deltas.py
--- a/mercurial/revlogutils/deltas.py
+++ b/mercurial/revlogutils/deltas.py
@@ -916,7 +916,7 @@ class deltacomputer(object):
and currentbase != base
and self.revlog.length(currentbase) == 0):
currentbase = self.revlog.deltaparent(currentbase)
- if currentbase == base:
+ if self.revlog._lazydelta and currentbase == base:
delta = revinfo.cachedelta[1]
if delta is None:
delta = self._builddeltadiff(base, revinfo, fh)
diff --git a/tests/test-sparse-revlog.t b/tests/test-sparse-revlog.t
--- a/tests/test-sparse-revlog.t
+++ b/tests/test-sparse-revlog.t
@@ -40,7 +40,7 @@ repeatedly while some of it changes rare
> maxchainlen = 15
> [storage]
> revlog.optimize-delta-parent-choice = yes
- > revlog.reuse-external-delta-parent = no
+ > revlog.reuse-external-delta = no
> EOF
$ hg init sparse-repo
$ cd sparse-repo
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