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.
# stack.py - Mercurial functions for stack definition
#
# 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.
def getstack(repo, rev=None):
"""return a sorted smartrev of the stack containing either rev if it is
not None or the current working directory parent.
The stack will always contain all drafts changesets which are ancestors to
the revision and are not merges.
"""
if rev is None:
rev = b'.'
revspec = b'only(%s) and not public() and not ::merge()'
revisions = repo.revs(revspec, rev)
revisions.sort()
return revisions