comparison hgext/obsolete.py @ 334:fb83210bce32 stable

obsolete: move to official binary format

332:36e2016d6563

from mercurial.i18n import _

import base64
import json

from mercurial import util
from mercurial import context
from mercurial import revset
from mercurial import scmutil

def _precursors(repo, s):
    """Precursor of a changeset"""
    cs = set()
    nm = repo.changelog.nodemap
    markerbysubj = repo.obsoletestore.subjects
    for r in s:
        for p in markerbysubj.get(repo[r].node(), ()):
            pr = nm.get(p['object'])
            if pr is not None:
                cs.add(pr)
    return cs

def revsetprecursors(repo, subset, x):

def _allprecursors(repo, s):  # XXX we need a better naming
    """transitive precursors of a subset"""
    toproceed = [repo[r].node() for r in s]
    seen = set()
    allsubjects = repo.obsoletestore.subjects
    while toproceed:
        nc = toproceed.pop()
        for mark in allsubjects.get(nc, ()):
            np = mark['object']
            if np not in seen:
                seen.add(np)
                toproceed.append(np)
    nm = repo.changelog.nodemap
    cs = set()

def _successors(repo, s):
    """Successors of a changeset"""
    cs = set()
    nm = repo.changelog.nodemap
    markerbyobj = repo.obsoletestore.objects
    for r in s:
        for p in markerbyobj.get(repo[r].node(), ()):
            for sub in p['subjects']:
                sr = nm.get(sub)
                if sr is not None:
                    cs.add(sr)
    return cs

def _allsuccessors(repo, s):  # XXX we need a better naming
    """transitive successors of a subset"""
    toproceed = [repo[r].node() for r in s]
    seen = set()
    allobjects = repo.obsoletestore.objects
    while toproceed:
        nc = toproceed.pop()
        for mark in allobjects.get(nc, ()):
            for sub in mark['subjects']:
                if sub not in seen:
                    seen.add(sub)
                    toproceed.append(sub)
    nm = repo.changelog.nodemap
    cs = set()

        pass  # rebase not found

# Pushkey mechanism for mutable
#########################################

def pushobsolete(repo, key, old, raw):
    """push obsolete relation through pushkey"""
    assert key == "markers"
    l = repo.lock()
    try:
        tmp = StringIO()
        tmp.write(raw)
        tmp.seek(0)
        repo.obsoletestore.load(tmp)
        repo.obsoletestore._dirty = True # XXX meh
        return 1
    finally:
        l.release()

def listobsolete(repo):
    """dump all obsolete relation in

    XXX this have be improved"""
    tmp = StringIO()
    repo.obsoletestore.save(tmp)
    return {'markers': base64.b64encode(tmp.getvalue())}

pushkey.register('obsolete', pushobsolete, listobsolete)

### Discovery wrapping
#############################

class blist(list, object):

                for branch, nodes in oldbm.iteritems():
                    nodes = list(nodes)
                    new = set()
                    while nodes:
                        n = nodes.pop()
                        if n in repo.obsoletestore.objects:
                            markers = repo.obsoletestore.objects[n]
                            for mark in markers:
                                for newernode in mark['subjects']:
                                    if newernode is not None:
                                        nodes.append(newernode)
                        else:
                            new.add(n)
                    if new:

@command('debugconvertobsolete', [], '')
def cmddebugconvertobsolete(ui, repo):
    """import markers from an .hg/obsolete-relations file"""
    cnt = 0
    l = repo.lock()
    try:
        repo._importoldobsolete = True
        store = repo.obsoletestore
        try:
            f = repo.opener('obsolete-relations')
            try:
                for line in f:
                    subhex, objhex = line.split()
                    sub = bin(subhex)
                    obj = bin(objhex)
                    newmarker = {
                        'subjects': (sub==nullid) and [] or [sub],
                        'object': obj,
                        'date':  util.makedate(),
                        'user': ui.username(),
                        'reason': 'import from older format.',
                        }
                    store.new(newmarker)
                    store._dirty = True
                    cnt += 1
            finally:
                f.close()
            util.unlink(repo.join('obsolete-relations'))
        except IOError:
            ui.warn('nothing to do\n')
            pass
    finally:
        del repo._importoldobsolete
        l.release()
    ui.status('%i obsolete marker converted\n' % cnt)

@command('debugsuccessors', [], '')
def cmddebugsuccessors(ui, repo):
    """dump obsolete changesets and their successors

    Each line matches an existing marker, the first identifier is the
    obsolete changeset identifier, followed by it successors.
    """
    lock = repo.lock()
    try:
        allsuccessors = repo.obsoletestore.objects
        for old in sorted(allsuccessors):
            successors = [sorted(m['subjects']) for m in allsuccessors[old]]
            for i, group in enumerate(sorted(successors)):
                ui.write('%s' % short(old))
                for new in group:
                    ui.write(' %s' % short(new))
                ui.write('\n')

    oldnode = old.node()
    new = orig(ui, repo, commitfunc, old, *args, **kwargs)
    if new != oldnode:
        lock = repo.lock()
        try:
            newmarker = {
                'subjects':  [new],
                'object': oldnode,
                'date':  util.makedate(),
                'user': ui.username(),
                'reason': 'commit --amend',
                }
            repo.obsoletestore.new(newmarker)
            repo._clearobsoletecache()
            repo._turn_extinct_secret()
        finally:
            lock.release()
    return new

def newerversion(repo, obs):
    """Return the newer version of an obsolete changeset"""
    toproceed = set([(obs,)])
    # XXX known optimization available
    newer = set()
    objectrels = repo.obsoletestore.objects
    while toproceed:
        current = toproceed.pop()
        assert len(current) <= 1, 'splitting not handled yet. %r' % current
        if current:
            n, = current
            if n in objectrels:
                markers = objectrels[n]
                for mark in markers:
                    toproceed.add(tuple(mark['subjects']))
            else:
                newer.add(tuple(current))
        else:
            newer.add(())
    return sorted(newer)

        else:
            a.update(str(marker[key]))
    a.update('\0')
    return a.digest()

class obsoletestore(object):
    """Store obsolete relations

    Relation are stored in three mapping. All mapping have "obsolete markers"
    as values::

        {'id': "unique id of the obsolete marker"
         'subjects': "0-N newer version of changeset in "object" (as ordered list)
         'object': "old and obsolete version"
         'date': "When was this marker created ?"
         'user': "Who did that ?"
         'reason': "Why was it done"
        }

    Three keys exists

    :self._markers: "id" -> marker

    :self.subjects: "subject" -> set(marker)

    :self.objects: "object" -> set(marker)
    """

    def __init__(self):
        self._markers = {}
        self.subjects = {}
        self.objects = {}
        self._dirty = False # should be on repo

    def new(self, marker):
        """Add a *new* marker to the store. computing it's ID"""
        mid = marker['id'] = markerid(marker)
        self._insert(marker)
        self._dirty = True
        return mid

    def _insert(self, marker):
        if marker['id'] not in self._markers:
            self._markers[marker['id']] = marker
            add2set(self.objects, marker['object'], marker)
            for subj in marker['subjects']:
                add2set(self.subjects, subj, marker)

    def save(self, stream):
        markers = []
        for mark in self._markers.itervalues():
            jmark = mark.copy()
            jmark['id'] = hex(jmark['id'])
            jmark['subjects'] = [hex(n) for n in jmark['subjects']]
            jmark['object'] = hex(jmark['object'])
            markers.append(jmark)
        json.dump(markers, stream, indent=4)

    def load(self, stream):
        for mark in json.load(stream):
            mark['id'] = bin(mark['id'])
            mark['subjects'] = [bin(n) for n in mark['subjects']]
            mark['object'] = bin(mark['object'])
            self._insert(mark)

def writeobsolete(repo):
    """wire obsolete data on disk"""
    f = repo.sopener('obsoletemarkers', 'w', atomictemp=True)
    try:
        repo.obsoletestore.save(f)
        repo._dirty = False
    finally:
        f.close()


### repo subclassing
#############################

        ### Public method
        def obsoletedby(self, node):
            """return the set of node that make <node> obsolete (obj)"""
            others = set()
            for marker in self.obsoletestore.objects.get(node, []):
                others.update(marker['subjects'])
            return others

        def obsolete(self, node):
            """return the set of node that <node> make obsolete (sub)"""
            return set(marker['object'] for marker in self.obsoletestore.subjects.get(node, []))

        @util.propertycache
        def obsoletestore(self):
            if not getattr(self, '_importoldobsolete', False):
                try:
                    f = self.opener('obsolete-relations')
                    f.close()
                    raise util.Abort('old format of obsolete marker detected!\n'
                                     'run `hg debugconvertobsolete` once.')
                except IOError:
                    pass
            store = obsoletestore()
            try:
                f = self.sopener('obsoletemarkers')
                store.load(f)
            except IOError:
                pass
            return store

        @util.propertycache
        def _obsoleteset(self):
            """the set of obsolete revision"""
            obs = set()
            nm = self.changelog.nodemap
            for obj in self.obsoletestore.objects:
                try: # /!\api change in Hg 2.2 (e8d37b78acfb22ae2c1fb126c2)/!\
                    rev = nm.get(obj)
                except TypeError:  #XXX to remove while breaking Hg 2.1 support
                    rev = nm.get(obj, None)
                if rev is not None:

                    self.ui.warn(
                        _("%(sub)s try to obsolete immutable changeset %(obj)s\n")
                        % {'sub': short(sub), 'obj': short(obj)})
            lock = self.lock()
            try:
                newmarker = {
                    'subjects': (sub==nullid) and [] or [sub],
                    'object': obj,
                    'date':  util.makedate(),
                    'user': ui.username(),
                    'reason': 'unknown',
                    }
                mid = self.obsoletestore.new(newmarker)
                self._clearobsoletecache()
                self._turn_extinct_secret()
                return mid
            finally:
                lock.release()

        def lock(self, *args, **kwargs):
            l = olock(*args, **kwargs)
            if not getattr(l.releasefn, 'obspatched', False):
                oreleasefn = l.releasefn
                def releasefn(*args, **kwargs):
                    if self.obsoletestore._dirty:
                        writeobsolete(self)
                    oreleasefn(*args, **kwargs)
                releasefn.obspatched = True
                l.releasefn = releasefn
            return l

        def _readobsrels(self):
            """Read obsolete relation on disk"""
            # XXX handle lock
            try:
                f = self.opener('obsolete-relations')
                try:
                    return _obsdeserialise(f)
                finally:
                    f.close()
            except IOError:
                return {}


        ### pull // push support

        def pull(self, remote, *args, **kwargs):
            """wrapper around push that push obsolete relation"""
            l = repo.lock()
            try:
                result = opull(remote, *args, **kwargs)
                if 'obsolete' in remote.listkeys('namespaces'):
                    tmp = StringIO()
                    rels = remote.listkeys('obsolete')['markers']
                    tmp.write(base64.b64decode(rels))
                    tmp.seek(0)
                    repo.obsoletestore.load(tmp)
                    repo.obsoletestore._dirty = True # XXX meh
                    self._clearobsoletecache()
                self._turn_extinct_secret()
                return result
            finally:
                l.release()

        def push(self, remote, *args, **opts):
            """wrapper around pull that pull obsolete relation"""
            self._turn_extinct_secret()
            result = opush(remote, *args, **opts)
            if 'obsolete' in remote.listkeys('namespaces'):
                tmp = StringIO()
                self.obsoletestore.save(tmp)
                remote.pushkey('obsolete', 'markers', '', tmp.getvalue())
            self._turn_extinct_secret()

            return result


        ### rollback support

        # /!\ api change in  Hg 2.2 (97efd26eb9576f39590812ea9) /!\
        if util.safehasattr(repo, '_journalfiles'): # Hg 2.2
            def _journalfiles(self):
                return o_journalfiles() + (self.sjoin('journal.obsoletemarkers'),) 

            def _writejournal(self, desc):
                """wrapped version of _writejournal that save obsolete data"""
                o_writejournal(desc)
                filename = 'obsoletemarkers'
                filepath = self.sjoin(filename)
                if os.path.exists(filepath):
                    journalname = 'journal.' + filename
                    journalpath = self.sjoin(journalname)
                    util.copyfile(filepath, journalpath)

        else: # XXX removing this bloc will break Hg 2.1 support
            def _writejournal(self, desc):
                """wrapped version of _writejournal that save obsolete data"""
                entries = list(o_writejournal(desc))
                filename = 'obsoletemarkers'
                filepath = self.sjoin(filename)
                if  os.path.exists(filepath):
                    journalname = 'journal.' + filename
                    journalpath = self.sjoin(journalname)
                    util.copyfile(filepath, journalpath)

        def _rollback(self, dryrun, force):
            """wrapped version of _rollback that restore obsolete data"""
            ret = o_rollback(dryrun, force)
            if not (ret or dryrun): #rollback did not failed
                src = self.sjoin('undo.obsoletemarkers')
                dst = self.sjoin('obsoletemarkers')
                if os.path.exists(src):
                    util.rename(src, dst)
                elif os.path.exists(dst):
                    # If no state was saved because the file did not existed before.
                    os.unlink(dst)
                # invalidate cache
                self.__dict__.pop('obsoletestore', None)
            return ret

        @storecache('00changelog.i')
        def changelog(self):
            # << copy pasted from mercurial source

334:fb83210bce32

from mercurial.i18n import _

import base64
import json

import struct
from mercurial import util, base85

_pack = struct.pack
_unpack = struct.unpack

from mercurial import util
from mercurial import context
from mercurial import revset
from mercurial import scmutil

def _precursors(repo, s):
    """Precursor of a changeset"""
    cs = set()
    nm = repo.changelog.nodemap
    markerbysubj = repo.obsstore.successors
    for r in s:
        for p in markerbysubj.get(repo[r].node(), ()):
            pr = nm.get(p[0])
            if pr is not None:
                cs.add(pr)
    return cs

def revsetprecursors(repo, subset, x):

def _allprecursors(repo, s):  # XXX we need a better naming
    """transitive precursors of a subset"""
    toproceed = [repo[r].node() for r in s]
    seen = set()
    allsubjects = repo.obsstore.successors
    while toproceed:
        nc = toproceed.pop()
        for mark in allsubjects.get(nc, ()):
            np = mark[0]
            if np not in seen:
                seen.add(np)
                toproceed.append(np)
    nm = repo.changelog.nodemap
    cs = set()

def _successors(repo, s):
    """Successors of a changeset"""
    cs = set()
    nm = repo.changelog.nodemap
    markerbyobj = repo.obsstore.precursors
    for r in s:
        for p in markerbyobj.get(repo[r].node(), ()):
            for sub in p[1]:
                sr = nm.get(sub)
                if sr is not None:
                    cs.add(sr)
    return cs

def _allsuccessors(repo, s):  # XXX we need a better naming
    """transitive successors of a subset"""
    toproceed = [repo[r].node() for r in s]
    seen = set()
    allobjects = repo.obsstore.precursors
    while toproceed:
        nc = toproceed.pop()
        for mark in allobjects.get(nc, ()):
            for sub in mark[1]:
                if sub not in seen:
                    seen.add(sub)
                    toproceed.append(sub)
    nm = repo.changelog.nodemap
    cs = set()

        pass  # rebase not found

# Pushkey mechanism for mutable
#########################################

def listmarkers(repo):
    """List markers over pushkey"""
    if not repo.obsstore:
        return {}
    data = repo.obsstore._writemarkers()
    return {'dump': base85.b85encode(data)}

def pushmarker(repo, key, old, new):
    """Push markers over pushkey"""
    if key != 'dump':
        repo.ui.warn(_('unknown key: %r') % key)
        return 0
    if old:
        repo.ui.warn(_('unexpected old value') % key)
        return 0
    data = base85.b85decode(new)
    lock = repo.lock()
    try:
        repo.obsstore.mergemarkers(data)
        return 1
    finally:
        lock.release()

pushkey.register('obsolete', pushmarker, listmarkers)

### Discovery wrapping
#############################

class blist(list, object):

                for branch, nodes in oldbm.iteritems():
                    nodes = list(nodes)
                    new = set()
                    while nodes:
                        n = nodes.pop()
                        if n in repo.obsstore.precursors:
                            markers = repo.obsstore.precursors[n]
                            for mark in markers:
                                for newernode in mark[1]:
                                    if newernode is not None:
                                        nodes.append(newernode)
                        else:
                            new.add(n)
                    if new:

@command('debugconvertobsolete', [], '')
def cmddebugconvertobsolete(ui, repo):
    """import markers from an .hg/obsolete-relations file"""
    cnt = 0
    l = repo.lock()
    some = False
    try:
        repo._importoldobsolete = True
        store = repo.obsstore
        ### very first format
        try:
            f = repo.opener('obsolete-relations')
            try:
                some = True
                for line in f:
                    subhex, objhex = line.split()
                    suc = bin(subhex)
                    prec = bin(objhex)
                    sucs = (suc==nullid) and [] or [suc]
                    meta = {
                        'date':  '%i %i' % util.makedate(),
                        'user': ui.username(),
                        }
                    store.create(prec, sucs, 0, meta)
                    cnt += 1
            finally:
                f.close()
            util.unlink(repo.join('obsolete-relations'))
        except IOError:
            pass
        ### second (json) format
        data = repo.sopener.tryread('obsoletemarkers')
        if data:
            some = True
            for oldmark in json.loads(data):
                del oldmark['id'] # dropped for now
                del oldmark['reason'] # unused until then
                oldmark['subjects'] = [bin(n) for n in oldmark['subjects']]
                oldmark['object'] = bin(oldmark['object'])
                oldmark['date'] = '%i %i' % tuple(oldmark['date'])
                store.create(oldmark.pop('object'),
                             oldmark.pop('subjects'),
                             0, oldmark)
                cnt += 1
            util.unlink(repo.sjoin('obsoletemarkers'))
    finally:
        del repo._importoldobsolete
        l.release()
    if not some:
            ui.warn('nothing to do\n')
    ui.status('%i obsolete marker converted\n' % cnt)

@command('debugsuccessors', [], '')
def cmddebugsuccessors(ui, repo):
    """dump obsolete changesets and their successors

    Each line matches an existing marker, the first identifier is the
    obsolete changeset identifier, followed by it successors.
    """
    lock = repo.lock()
    try:
        allsuccessors = repo.obsstore.precursors
        for old in sorted(allsuccessors):
            successors = [sorted(m[1]) for m in allsuccessors[old]]
            for i, group in enumerate(sorted(successors)):
                ui.write('%s' % short(old))
                for new in group:
                    ui.write(' %s' % short(new))
                ui.write('\n')

    oldnode = old.node()
    new = orig(ui, repo, commitfunc, old, *args, **kwargs)
    if new != oldnode:
        lock = repo.lock()
        try:
            meta = {
                'subjects':  [new],
                'object': oldnode,
                'date':  util.makedate(),
                'user': ui.username(),
                'reason': 'commit --amend',
                }
            repo.obsstore.create(oldnode, [new], 0, meta)
            repo._clearobsoletecache()
            repo._turn_extinct_secret()
        finally:
            lock.release()
    return new

def newerversion(repo, obs):
    """Return the newer version of an obsolete changeset"""
    toproceed = set([(obs,)])
    # XXX known optimization available
    newer = set()
    objectrels = repo.obsstore.precursors
    while toproceed:
        current = toproceed.pop()
        assert len(current) <= 1, 'splitting not handled yet. %r' % current
        if current:
            n, = current
            if n in objectrels:
                markers = objectrels[n]
                for mark in markers:
                    toproceed.add(tuple(mark[1]))
            else:
                newer.add(tuple(current))
        else:
            newer.add(())
    return sorted(newer)

        else:
            a.update(str(marker[key]))
    a.update('\0')
    return a.digest()

# mercurial backport

def encodemeta(meta):
    """Return encoded metadata string to string mapping.

    Assume no ':' in key and no '\0' in both key and value."""
    for key, value in meta.iteritems():
        if ':' in key or '\0' in key:
            raise ValueError("':' and '\0' are forbidden in metadata key'")
        if '\0' in value:
            raise ValueError("':' are forbidden in metadata value'")
    return '\0'.join(['%s:%s' % (k, meta[k]) for k in sorted(meta)])

def decodemeta(data):
    """Return string to string dictionary from encoded version."""
    d = {}
    for l in data.split('\0'):
        if l:
            key, value = l.split(':')
            d[key] = value
    return d

# data used for parsing and writing
_fmversion = 0
_fmfixed   = '>BIB20s'
_fmnode = '20s'
_fmfsize = struct.calcsize(_fmfixed)
_fnodesize = struct.calcsize(_fmnode)

def _readmarkers(data):
    """Read and enumerate markers from raw data"""
    off = 0
    diskversion = _unpack('>B', data[off:off + 1])[0]
    off += 1
    if diskversion != _fmversion:
        raise util.Abort(_('parsing obsolete marker: unknown version %r')
                         % diskversion)

    # Loop on markers
    l = len(data)
    while off + _fmfsize <= l:
        # read fixed part
        cur = data[off:off + _fmfsize]
        off += _fmfsize
        nbsuc, mdsize, flags, pre = _unpack(_fmfixed, cur)
        # read replacement
        sucs = ()
        if nbsuc:
            s = (_fnodesize * nbsuc)
            cur = data[off:off + s]
            sucs = _unpack(_fmnode * nbsuc, cur)
            off += s
        # read metadata
        # (metadata will be decoded on demand)
        metadata = data[off:off + mdsize]
        if len(metadata) != mdsize:
            raise util.Abort(_('parsing obsolete marker: metadata is too '
                               'short, %d bytes expected, got %d')
                             % (len(metadata), mdsize))
        off += mdsize
        yield (pre, sucs, flags, metadata)

class obsstore(object):
    """Store obsolete markers

    Markers can be accessed with two mappings:
    - precursors: old -> set(new)
    - successors: new -> set(old)
    """

    def __init__(self):
        self._all = []
        # new markers to serialize
        self._new = []
        self.precursors = {}
        self.successors = {}

    def __iter__(self):
        return iter(self._all)

    def __nonzero__(self):
        return bool(self._all)

    def create(self, prec, succs=(), flag=0, metadata=None):
        """obsolete: add a new obsolete marker

        * ensuring it is hashable
        * check mandatory metadata
        * encode metadata
        """
        if metadata is None:
            metadata = {}
        if len(prec) != 20:
            raise ValueError(prec)
        for succ in succs:
            if len(succ) != 20:
                raise ValueError(prec)
        marker = (str(prec), tuple(succs), int(flag), encodemeta(metadata))
        self.add(marker)

    def add(self, marker):
        """Add a new marker to the store

        This marker still needs to be written to disk"""
        self._new.append(marker)
        self._load(marker)

    def loadmarkers(self, data):
        """Load all markers in data, mark them as known."""
        for marker in _readmarkers(data):
            self._load(marker)

    def mergemarkers(self, data):
        other = set(_readmarkers(data))
        local = set(self._all)
        new = other - local
        for marker in new:
            self.add(marker)

    def flushmarkers(self, stream):
        """Write all markers to a stream

        After this operation, "new" markers are considered "known"."""
        self._writemarkers(stream)
        self._new[:] = []

    def _load(self, marker):
        self._all.append(marker)
        pre, sucs = marker[:2]
        self.precursors.setdefault(pre, set()).add(marker)
        for suc in sucs:
            self.successors.setdefault(suc, set()).add(marker)

    def _writemarkers(self, stream=None):
        # Kept separate from flushmarkers(), it will be reused for
        # markers exchange.
        if stream is None:
            final = []
            w = final.append
        else:
            w = stream.write
        w(_pack('>B', _fmversion))
        for marker in self._all:
            pre, sucs, flags, metadata = marker
            nbsuc = len(sucs)
            format = _fmfixed + (_fmnode * nbsuc)
            data = [nbsuc, len(metadata), flags, pre]
            data.extend(sucs)
            w(_pack(format, *data))
            w(metadata)
        if stream is None:
            return ''.join(final)


### repo subclassing
#############################

        ### Public method
        def obsoletedby(self, node):
            """return the set of node that make <node> obsolete (obj)"""
            others = set()
            for marker in self.obsstore.precursors.get(node, []):
                others.update(marker[1])
            return others

        def obsolete(self, node):
            """return the set of node that <node> make obsolete (sub)"""
            return set(marker[0] for marker in self.obsstore.successors.get(node, []))

        @storecache('obsstore')
        def obsstore(self):
            if not getattr(self, '_importoldobsolete', False):
                data = repo.opener.tryread('obsolete-relations')
                if not data:
                    data = repo.sopener.tryread('obsoletemarkers')
                if data:
                    raise util.Abort('old format of obsolete marker detected!\n'
                                     'run `hg debugconvertobsolete` once.')
            store = obsstore()
            data = self.sopener.tryread('obsstore')
            if data:
                store.loadmarkers(data)
            return store

        @util.propertycache
        def _obsoleteset(self):
            """the set of obsolete revision"""
            obs = set()
            nm = self.changelog.nodemap
            for obj in self.obsstore.precursors:
                try: # /!\api change in Hg 2.2 (e8d37b78acfb22ae2c1fb126c2)/!\
                    rev = nm.get(obj)
                except TypeError:  #XXX to remove while breaking Hg 2.1 support
                    rev = nm.get(obj, None)
                if rev is not None:

                    self.ui.warn(
                        _("%(sub)s try to obsolete immutable changeset %(obj)s\n")
                        % {'sub': short(sub), 'obj': short(obj)})
            lock = self.lock()
            try:
                meta = {
                    'date':  util.makedate(),
                    'user': ui.username(),
                    'reason': 'unknown',
                    }
                subs = (sub == nullid) and [] or [sub]
                mid = self.obsstore.create(obj, subs, 0, meta)
                self._clearobsoletecache()
                self._turn_extinct_secret()
                return mid
            finally:
                lock.release()

        def lock(self, *args, **kwargs):
            l = olock(*args, **kwargs)
            if not getattr(l.releasefn, 'obspatched', False):
                oreleasefn = l.releasefn
                def releasefn(*args, **kwargs):
                    if 'obsstore' in vars(self) and self.obsstore._new:
                        f = self.sopener('obsstore', 'wb', atomictemp=True)
                        try:
                            self.obsstore.flushmarkers(f)
                            f.close()
                        except: # re-raises
                            f.discard()
                            raise
                    oreleasefn(*args, **kwargs)
                releasefn.obspatched = True
                l.releasefn = releasefn
            return l


        ### pull // push support

        def pull(self, remote, *args, **kwargs):
            """wrapper around push that push obsolete relation"""
            l = repo.lock()
            try:
                result = opull(remote, *args, **kwargs)
                remoteobs = remote.listkeys('obsolete')
                if 'dump' in remoteobs:
                    data = base85.b85decode(remoteobs['dump'])
                    self.obsstore.mergemarkers(data)
                    self._clearobsoletecache()
                    self._turn_extinct_secret()
                    return result
            finally:
                l.release()

        def push(self, remote, *args, **opts):
            """wrapper around pull that pull obsolete relation"""
            self._turn_extinct_secret()
            result = opush(remote, *args, **opts)
            if 'obsolete' in self.listkeys('namespaces') and self.obsstore:
                data = self.obsstore._writemarkers()
                r = remote.pushkey('obsolete', 'dump', '',
                                   base85.b85encode(data))
                if not r:
                    self.ui.warn(_('failed to push obsolete markers!\n'))
            self._turn_extinct_secret()

            return result


        ### rollback support

        # /!\ api change in  Hg 2.2 (97efd26eb9576f39590812ea9) /!\
        if util.safehasattr(repo, '_journalfiles'): # Hg 2.2
            def _journalfiles(self):
                return o_journalfiles() + (self.sjoin('journal.obsstore'),) 

            def _writejournal(self, desc):
                """wrapped version of _writejournal that save obsolete data"""
                o_writejournal(desc)
                filename = 'obsstore'
                filepath = self.sjoin(filename)
                if os.path.exists(filepath):
                    journalname = 'journal.' + filename
                    journalpath = self.sjoin(journalname)
                    util.copyfile(filepath, journalpath)

        else: # XXX removing this bloc will break Hg 2.1 support
            def _writejournal(self, desc):
                """wrapped version of _writejournal that save obsolete data"""
                entries = list(o_writejournal(desc))
                filename = 'obsstore'
                filepath = self.sjoin(filename)
                if  os.path.exists(filepath):
                    journalname = 'journal.' + filename
                    journalpath = self.sjoin(journalname)
                    util.copyfile(filepath, journalpath)

        def _rollback(self, dryrun, force):
            """wrapped version of _rollback that restore obsolete data"""
            ret = o_rollback(dryrun, force)
            if not (ret or dryrun): #rollback did not failed
                src = self.sjoin('undo.obsstore')
                dst = self.sjoin('obsstore')
                if os.path.exists(src):
                    util.rename(src, dst)
                elif os.path.exists(dst):
                    # If no state was saved because the file did not existed before.
                    os.unlink(dst)
                # invalidate cache
                self.__dict__.pop('obsstore', None)
            return ret

        @storecache('00changelog.i')
        def changelog(self):
            # << copy pasted from mercurial source