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.
# bruterebase.py - brute force rebase testing
#
# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from mercurial import (
error,
registrar,
revsetlang,
)
from hgext import rebase
cmdtable = {}
command = registrar.command(cmdtable)
@command(b'debugbruterebase')
def debugbruterebase(ui, repo, source, dest):
"""for every non-empty subset of source, run rebase -r subset -d dest
Print one line summary for each subset. Assume obsstore is enabled.
"""
srevs = list(repo.revs(source))
with repo.wlock(), repo.lock():
repolen = len(repo)
cl = repo.changelog
def getdesc(rev):
result = cl.changelogrevision(rev).description
if rev >= repolen:
result += b"'"
return result
for i in range(1, 2 ** len(srevs)):
subset = [rev for j, rev in enumerate(srevs) if i & (1 << j) != 0]
spec = revsetlang.formatspec(b'%ld', subset)
tr = repo.transaction(b'rebase')
tr._report = lambda x: 0 # hide "transaction abort"
with ui.silent():
try:
rebase.rebase(ui, repo, dest=dest, rev=[spec])
except error.Abort as ex:
summary = b'ABORT: %s' % ex.message
except Exception as ex:
summary = b'CRASH: %s' % ex
else:
# short summary about new nodes
cl = repo.changelog
descs = []
for rev in range(repolen, len(repo)):
desc = b'%s:' % getdesc(rev)
for prev in cl.parentrevs(rev):
if prev > -1:
desc += getdesc(prev)
descs.append(desc)
descs.sort()
summary = b' '.join(descs)
repo.vfs.tryunlink(b'rebasestate')
subsetdesc = b''.join(getdesc(rev) for rev in subset)
ui.write(b'%s: %s\n' % (subsetdesc.rjust(len(srevs)), summary))
tr.abort()