repair: implement requirements checking for upgrades
This commit introduces functionality for upgrading a repository in
place. The first part that's implemented is testing for upgrade
"compatibility." This is done by examining repository requirements.
There are 5 functions returning sets of requirements that control
upgrading. Why so many functions? Mainly to support extensions.
Functions are easier to monkeypatch than module variables.
Astute readers will see that we don't support "manifestv2" and
"treemanifest" requirements in the upgrade mechanism. I don't have
a great answer for why other than this is a complex set of patches
and I don't want to deal with the complexity of these experimental
features just yet. We can teach the upgrade mechanism about them
later, once the basic upgrade mechanism is in place.
This commit also introduces the "upgraderepo" function. This will be
our main routine for performing an in-place upgrade. Currently, it
just implements requirements checking. The structure of some code in
this function may look a bit weird (e.g. the inline function that is
only called once). But this will make sense after future commits.
# 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
msg = _('programming error: cannot strip from inside a transaction')
raise error.Abort(msg, hint=_('contact your extension maintainer'))
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()
lock = tr = None
try:
lock = repo.lock()
tr = repo.transaction('repair')
bm.recordchange(tr)
tr.close()
finally:
tr.release()
lock.release()
# 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
def upgraderequiredsourcerequirements(repo):
"""Obtain requirements required to be present to upgrade a repo.
An upgrade will not be allowed if the repository doesn't have the
requirements returned by this function.
"""
return set([
# Introduced in Mercurial 0.9.2.
'revlogv1',
# Introduced in Mercurial 0.9.2.
'store',
])
def upgradeblocksourcerequirements(repo):
"""Obtain requirements that will prevent an upgrade from occurring.
An upgrade cannot be performed if the source repository contains a
requirements in the returned set.
"""
return set([
# The upgrade code does not yet support these experimental features.
# This is an artificial limitation.
'manifestv2',
'treemanifest',
# This was a precursor to generaldelta and was never enabled by default.
# It should (hopefully) not exist in the wild.
'parentdelta',
# Upgrade should operate on the actual store, not the shared link.
'shared',
])
def upgradesupportremovedrequirements(repo):
"""Obtain requirements that can be removed during an upgrade.
If an upgrade were to create a repository that dropped a requirement,
the dropped requirement must appear in the returned set for the upgrade
to be allowed.
"""
return set()
def upgradesupporteddestrequirements(repo):
"""Obtain requirements that upgrade supports in the destination.
If the result of the upgrade would create requirements not in this set,
the upgrade is disallowed.
Extensions should monkeypatch this to add their custom requirements.
"""
return set([
'dotencode',
'fncache',
'generaldelta',
'revlogv1',
'store',
])
def upgradeallowednewrequirements(repo):
"""Obtain requirements that can be added to a repository during upgrade.
This is used to disallow proposed requirements from being added when
they weren't present before.
We use a list of allowed requirement additions instead of a list of known
bad additions because the whitelist approach is safer and will prevent
future, unknown requirements from accidentally being added.
"""
return set([
'dotencode',
'fncache',
'generaldelta',
])
def upgraderepo(ui, repo, run=False, optimize=None):
"""Upgrade a repository in place."""
# Avoid cycle: cmdutil -> repair -> localrepo -> cmdutil
from . import localrepo
repo = repo.unfiltered()
# Ensure the repository can be upgraded.
missingreqs = upgraderequiredsourcerequirements(repo) - repo.requirements
if missingreqs:
raise error.Abort(_('cannot upgrade repository; requirement '
'missing: %s') % _(', ').join(sorted(missingreqs)))
blockedreqs = upgradeblocksourcerequirements(repo) & repo.requirements
if blockedreqs:
raise error.Abort(_('cannot upgrade repository; unsupported source '
'requirement: %s') %
_(', ').join(sorted(blockedreqs)))
# FUTURE there is potentially a need to control the wanted requirements via
# command arguments or via an extension hook point.
newreqs = localrepo.newreporequirements(repo)
noremovereqs = (repo.requirements - newreqs -
upgradesupportremovedrequirements(repo))
if noremovereqs:
raise error.Abort(_('cannot upgrade repository; requirement would be '
'removed: %s') % _(', ').join(sorted(noremovereqs)))
noaddreqs = (newreqs - repo.requirements -
upgradeallowednewrequirements(repo))
if noaddreqs:
raise error.Abort(_('cannot upgrade repository; do not support adding '
'requirement: %s') %
_(', ').join(sorted(noaddreqs)))
unsupportedreqs = newreqs - upgradesupporteddestrequirements(repo)
if unsupportedreqs:
raise error.Abort(_('cannot upgrade repository; do not support '
'destination requirement: %s') %
_(', ').join(sorted(unsupportedreqs)))
def printrequirements():
ui.write(_('requirements\n'))
ui.write(_(' preserved: %s\n') %
_(', ').join(sorted(newreqs & repo.requirements)))
if repo.requirements - newreqs:
ui.write(_(' removed: %s\n') %
_(', ').join(sorted(repo.requirements - newreqs)))
if newreqs - repo.requirements:
ui.write(_(' added: %s\n') %
_(', ').join(sorted(newreqs - repo.requirements)))
ui.write('\n')
if not run:
ui.write(_('performing an upgrade with "--run" will make the following '
'changes:\n\n'))
printrequirements()