branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
#
# tcsh completion for Mercurial
#
# This file has been auto-generated by tcsh_completion_build.sh for
# Mercurial Distributed SCM (version 1.7.5+157-8a220ae0b2ba)
#
# Copyright (C) 2005 TK Soh.
#
# This is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
complete hg \
'n/--cwd/d/' 'n/-R/d/' 'n/--repository/d/' \
'C/-/( -R --repository \
--cwd \
-y --noninteractive \
-q --quiet \
-v --verbose \
--config \
--debug \
--debugger \
--encoding \
--encodingmode \
--traceback \
--time \
--profile \
--version \
-h --help)/' \
'p/1/(add addremove annotate blame archive \
backout bisect bookmarks branch branches \
bundle cat clone commit ci \
copy cp debugancestor debugbuilddag debugcheckstate \
debugcommands debugcomplete debugdag debugdata debugdate \
debugfsinfo debugignore debugindex debugindexdot debuginstall \
debugpushkey debugrebuildstate debugrename debugrevspec debugsetparents \
debugstate debugsub debugwalk diff export \
forget grep heads help identify \
id import patch incoming in \
init locate log history manifest \
merge outgoing out parents paths \
pull push recover remove rm \
rename move mv resolve revert \
rollback root serve showconfig debugconfig \
status st summary sum tag \
tags tip unbundle update up \
checkout co verify version)/'