rebase: use matcher to optimize manifestmerge
The old merge code would call manifestmerge and calculate the complete diff
between the source to the destination. In many cases, like rebase, the vast
majority of differences between the source and destination are irrelevant
because they are differences between the destination and the common ancestor
only, and therefore don't affect the merge. Since most actions are 'keep', all
the effort to compute them is wasted.
Instead, let's compute the difference between the source and the common ancestor
and only perform the diff of those files against the merge destination. When
using treemanifest, this lets us avoid loading almost the entire tree when
rebasing from a very old ancestor. This speeds up rebase of an old stack of 27
commits by 20x.
In mozilla-central, without treemanifest, when rebasing a commit from
default~100000 to default, this speeds up the manifestmerge step from 2.6s to
1.2s. However, the additional diff adds an overhead to all manifestmerge calls,
especially for flat manifests. When rebasing a commit from default~1 to default
it appears to add 100ms in mozilla-central. While we could put this optimization
behind a flag, I think the fact that it makes merge O(number of changes being
applied) instead of O(number of changes between X and Y) justifies it.
# repair.py - functions for repository repair for mercurial
#
# Copyright 2005, 2006 Chris Mason <mason@suse.com>
# Copyright 2007 Matt Mackall
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import errno
import hashlib
from .i18n import _
from .node import short
from . import (
bundle2,
changegroup,
error,
exchange,
obsolete,
util,
)
def _bundle(repo, bases, heads, node, suffix, compress=True):
"""create a bundle with the specified revisions as a backup"""
cgversion = changegroup.safeversion(repo)
cg = changegroup.changegroupsubset(repo, bases, heads, 'strip',
version=cgversion)
backupdir = "strip-backup"
vfs = repo.vfs
if not vfs.isdir(backupdir):
vfs.mkdir(backupdir)
# Include a hash of all the nodes in the filename for uniqueness
allcommits = repo.set('%ln::%ln', bases, heads)
allhashes = sorted(c.hex() for c in allcommits)
totalhash = hashlib.sha1(''.join(allhashes)).hexdigest()
name = "%s/%s-%s-%s.hg" % (backupdir, short(node), totalhash[:8], suffix)
comp = None
if cgversion != '01':
bundletype = "HG20"
if compress:
comp = 'BZ'
elif compress:
bundletype = "HG10BZ"
else:
bundletype = "HG10UN"
return bundle2.writebundle(repo.ui, cg, name, bundletype, vfs,
compression=comp)
def _collectfiles(repo, striprev):
"""find out the filelogs affected by the strip"""
files = set()
for x in xrange(striprev, len(repo)):
files.update(repo[x].files())
return sorted(files)
def _collectbrokencsets(repo, files, striprev):
"""return the changesets which will be broken by the truncation"""
s = set()
def collectone(revlog):
_, brokenset = revlog.getstrippoint(striprev)
s.update([revlog.linkrev(r) for r in brokenset])
collectone(repo.manifestlog._revlog)
for fname in files:
collectone(repo.file(fname))
return s
def strip(ui, repo, nodelist, backup=True, topic='backup'):
# This function operates within a transaction of its own, but does
# not take any lock on the repo.
# Simple way to maintain backwards compatibility for this
# argument.
if backup in ['none', 'strip']:
backup = False
repo = repo.unfiltered()
repo.destroying()
cl = repo.changelog
# TODO handle undo of merge sets
if isinstance(nodelist, str):
nodelist = [nodelist]
striplist = [cl.rev(node) for node in nodelist]
striprev = min(striplist)
files = _collectfiles(repo, striprev)
saverevs = _collectbrokencsets(repo, files, striprev)
# Some revisions with rev > striprev may not be descendants of striprev.
# We have to find these revisions and put them in a bundle, so that
# we can restore them after the truncations.
# To create the bundle we use repo.changegroupsubset which requires
# the list of heads and bases of the set of interesting revisions.
# (head = revision in the set that has no descendant in the set;
# base = revision in the set that has no ancestor in the set)
tostrip = set(striplist)
saveheads = set(saverevs)
for r in cl.revs(start=striprev + 1):
if any(p in tostrip for p in cl.parentrevs(r)):
tostrip.add(r)
if r not in tostrip:
saverevs.add(r)
saveheads.difference_update(cl.parentrevs(r))
saveheads.add(r)
saveheads = [cl.node(r) for r in saveheads]
# compute base nodes
if saverevs:
descendants = set(cl.descendants(saverevs))
saverevs.difference_update(descendants)
savebases = [cl.node(r) for r in saverevs]
stripbases = [cl.node(r) for r in tostrip]
# For a set s, max(parents(s) - s) is the same as max(heads(::s - s)), but
# is much faster
newbmtarget = repo.revs('max(parents(%ld) - (%ld))', tostrip, tostrip)
if newbmtarget:
newbmtarget = repo[newbmtarget.first()].node()
else:
newbmtarget = '.'
bm = repo._bookmarks
updatebm = []
for m in bm:
rev = repo[bm[m]].rev()
if rev in tostrip:
updatebm.append(m)
# create a changegroup for all the branches we need to keep
backupfile = None
vfs = repo.vfs
node = nodelist[-1]
if backup:
backupfile = _bundle(repo, stripbases, cl.heads(), node, topic)
repo.ui.status(_("saved backup bundle to %s\n") %
vfs.join(backupfile))
repo.ui.log("backupbundle", "saved backup bundle to %s\n",
vfs.join(backupfile))
tmpbundlefile = None
if saveheads:
# do not compress temporary bundle if we remove it from disk later
tmpbundlefile = _bundle(repo, savebases, saveheads, node, 'temp',
compress=False)
mfst = repo.manifestlog._revlog
curtr = repo.currenttransaction()
if curtr is not None:
del curtr # avoid carrying reference to transaction for nothing
raise error.ProgrammingError('cannot strip from inside a transaction')
try:
with repo.transaction("strip") as tr:
offset = len(tr.entries)
tr.startgroup()
cl.strip(striprev, tr)
mfst.strip(striprev, tr)
if 'treemanifest' in repo.requirements: # safe but unnecessary
# otherwise
for unencoded, encoded, size in repo.store.datafiles():
if (unencoded.startswith('meta/') and
unencoded.endswith('00manifest.i')):
dir = unencoded[5:-12]
repo.manifestlog._revlog.dirlog(dir).strip(striprev, tr)
for fn in files:
repo.file(fn).strip(striprev, tr)
tr.endgroup()
for i in xrange(offset, len(tr.entries)):
file, troffset, ignore = tr.entries[i]
with repo.svfs(file, 'a', checkambig=True) as fp:
fp.truncate(troffset)
if troffset == 0:
repo.store.markremoved(file)
if tmpbundlefile:
ui.note(_("adding branch\n"))
f = vfs.open(tmpbundlefile, "rb")
gen = exchange.readbundle(ui, f, tmpbundlefile, vfs)
if not repo.ui.verbose:
# silence internal shuffling chatter
repo.ui.pushbuffer()
if isinstance(gen, bundle2.unbundle20):
with repo.transaction('strip') as tr:
tr.hookargs = {'source': 'strip',
'url': 'bundle:' + vfs.join(tmpbundlefile)}
bundle2.applybundle(repo, gen, tr, source='strip',
url='bundle:' + vfs.join(tmpbundlefile))
else:
gen.apply(repo, 'strip', 'bundle:' + vfs.join(tmpbundlefile),
True)
if not repo.ui.verbose:
repo.ui.popbuffer()
f.close()
repo._phasecache.invalidate()
for m in updatebm:
bm[m] = repo[newbmtarget].node()
with repo.lock():
with repo.transaction('repair') as tr:
bm.recordchange(tr)
# remove undo files
for undovfs, undofile in repo.undofiles():
try:
undovfs.unlink(undofile)
except OSError as e:
if e.errno != errno.ENOENT:
ui.warn(_('error removing %s: %s\n') %
(undovfs.join(undofile), str(e)))
except: # re-raises
if backupfile:
ui.warn(_("strip failed, backup bundle stored in '%s'\n")
% vfs.join(backupfile))
if tmpbundlefile:
ui.warn(_("strip failed, unrecovered changes stored in '%s'\n")
% vfs.join(tmpbundlefile))
ui.warn(_("(fix the problem, then recover the changesets with "
"\"hg unbundle '%s'\")\n") % vfs.join(tmpbundlefile))
raise
else:
if tmpbundlefile:
# Remove temporary bundle only if there were no exceptions
vfs.unlink(tmpbundlefile)
repo.destroyed()
# return the backup file path (or None if 'backup' was False) so
# extensions can use it
return backupfile
def rebuildfncache(ui, repo):
"""Rebuilds the fncache file from repo history.
Missing entries will be added. Extra entries will be removed.
"""
repo = repo.unfiltered()
if 'fncache' not in repo.requirements:
ui.warn(_('(not rebuilding fncache because repository does not '
'support fncache)\n'))
return
with repo.lock():
fnc = repo.store.fncache
# Trigger load of fncache.
if 'irrelevant' in fnc:
pass
oldentries = set(fnc.entries)
newentries = set()
seenfiles = set()
repolen = len(repo)
for rev in repo:
ui.progress(_('rebuilding'), rev, total=repolen,
unit=_('changesets'))
ctx = repo[rev]
for f in ctx.files():
# This is to minimize I/O.
if f in seenfiles:
continue
seenfiles.add(f)
i = 'data/%s.i' % f
d = 'data/%s.d' % f
if repo.store._exists(i):
newentries.add(i)
if repo.store._exists(d):
newentries.add(d)
ui.progress(_('rebuilding'), None)
if 'treemanifest' in repo.requirements: # safe but unnecessary otherwise
for dir in util.dirs(seenfiles):
i = 'meta/%s/00manifest.i' % dir
d = 'meta/%s/00manifest.d' % dir
if repo.store._exists(i):
newentries.add(i)
if repo.store._exists(d):
newentries.add(d)
addcount = len(newentries - oldentries)
removecount = len(oldentries - newentries)
for p in sorted(oldentries - newentries):
ui.write(_('removing %s\n') % p)
for p in sorted(newentries - oldentries):
ui.write(_('adding %s\n') % p)
if addcount or removecount:
ui.write(_('%d items added, %d removed from fncache\n') %
(addcount, removecount))
fnc.entries = newentries
fnc._dirty = True
with repo.transaction('fncache') as tr:
fnc.write(tr)
else:
ui.write(_('fncache already up to date\n'))
def stripbmrevset(repo, mark):
"""
The revset to strip when strip is called with -B mark
Needs to live here so extensions can use it and wrap it even when strip is
not enabled or not present on a box.
"""
return repo.revs("ancestors(bookmark(%s)) - "
"ancestors(head() and not bookmark(%s)) - "
"ancestors(bookmark() and not bookmark(%s))",
mark, mark, mark)
def deleteobsmarkers(obsstore, indices):
"""Delete some obsmarkers from obsstore and return how many were deleted
'indices' is a list of ints which are the indices
of the markers to be deleted.
Every invocation of this function completely rewrites the obsstore file,
skipping the markers we want to be removed. The new temporary file is
created, remaining markers are written there and on .close() this file
gets atomically renamed to obsstore, thus guaranteeing consistency."""
if not indices:
# we don't want to rewrite the obsstore with the same content
return
left = []
current = obsstore._all
n = 0
for i, m in enumerate(current):
if i in indices:
n += 1
continue
left.append(m)
newobsstorefile = obsstore.svfs('obsstore', 'w', atomictemp=True)
for bytes in obsolete.encodemarkers(left, True, obsstore._version):
newobsstorefile.write(bytes)
newobsstorefile.close()
return n