branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
# scmutil.py - Mercurial core utility functions
#
# Copyright Olivia Mackall <olivia@selenic.com> and other
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from . import repoview
def cachetocopy(srcrepo):
"""return the list of cache file valuable to copy during a clone"""
# In local clones we're copying all nodes, not just served
# ones. Therefore copy all branch caches over.
cachefiles = [b'branch2']
cachefiles += [b'branch2-%s' % f for f in repoview.filtertable]
cachefiles += [b'branch3']
cachefiles += [b'branch3-%s' % f for f in repoview.filtertable]
cachefiles += [b'rbc-names-v1', b'rbc-revs-v1']
cachefiles += [b'tags2']
cachefiles += [b'tags2-%s' % f for f in repoview.filtertable]
cachefiles += [b'hgtagsfnodes1']
return cachefiles