annotate hgext/obsolete.py @ 480:cd1d5b7308be

obsolete: ignore hidden changeset when resolving `branchname` revision

# obsolete.py - introduce the obsolete concept in mercurial.
#
# Copyright 2011 Pierre-Yves David <[e-mail]>
#                Logilab SA        <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""Introduce the Obsolete concept to mercurial

General concept
===============

This extension introduces the *obsolete* concept. The relation
``<changeset B> obsoletes <changeset A>`` denotes that ``<changeset B>``
is a new version of ``<changeset A>``.

The *obsolete* relations act as an history **orthogonal** to the regular
changesets history. Regular changesets history versions files. *Obsolete*
relations version changesets.

:obsolete:     a changeset that has been replaced by another one.
:unstable:     a changeset that is not obsolete but has an obsolete ancestor.
:suspended:    an obsolete changeset with unstable descendants.
:extinct:      an obsolete changeset without unstable descendants.
               (subject to garbage collection)

Another name for unstable could be out of sync.


Usage and Feature
=================


New commands
------------

Note that rebased changesets are now marked obsolete instead of being stripped.

"""



from mercurial import util

try:
    from mercurial import obsolete
    obsolete._enabled = True
except ImportError:
    raise util.Abort('Obsolete extension requires Mercurial 2.3 (or later)')

import sys
from mercurial.i18n import _
from mercurial import cmdutil
from mercurial import commands
from mercurial import context
from mercurial import discovery
from mercurial import error
from mercurial import extensions
from mercurial import localrepo
from mercurial import phases
from mercurial import revset
from mercurial import scmutil
from mercurial import templatekw
from mercurial import merge
from mercurial.node import bin, short, nullid

# This extension contains the following code
#
# - Extension Helper code
# - Obsolescence cache
# - ...
# - Older format compat



#####################################################################
### Extension helper                                              ###
#####################################################################

class exthelper(object):
    """Helper for modular extension setup

    A single helper should be instanciated for each extension. Helper
    methods are then used as decorator for various purpose.

    All decorators return the original function and may be chained.
    """

    def __init__(self):
        self._uicallables = []
        self._extcallables = []
        self._repocallables = []
        self._revsetsymbols = []
        self._templatekws = []
        self._commandwrappers = []
        self._extcommandwrappers = []
        self._functionwrappers = []
        self._duckpunchers = []

    def final_uisetup(self, ui):
        """Method to be used as the extension uisetup

        The following operations belong here:

        - Changes to ui.__class__ . The ui object that will be used to run the
          command has not yet been created. Changes made here will affect ui
          objects created after this, and in particular the ui that will be
          passed to runcommand
        - Command wraps (extensions.wrapcommand)
        - Changes that need to be visible to other extensions: because
          initialization occurs in phases (all extensions run uisetup, then all
          run extsetup), a change made here will be visible to other extensions
          during extsetup
        - Monkeypatch or wrap function (extensions.wrapfunction) of dispatch
          module members
        - Setup of pre-* and post-* hooks
        - pushkey setup
        """
        for cont, funcname, func in self._duckpunchers:
            setattr(cont, funcname, func)
        for command, wrapper in self._commandwrappers:
            extensions.wrapcommand(commands.table, command, wrapper)
        for cont, funcname, wrapper in self._functionwrappers:
            extensions.wrapfunction(cont, funcname, wrapper)
        for c in self._uicallables:
            c(ui)

    def final_extsetup(self, ui):
        """Method to be used as a the extension extsetup

        The following operations belong here:

        - Changes depending on the status of other extensions. (if
          extensions.find('mq'))
        - Add a global option to all commands
        - Register revset functions
        """
        knownexts = {}
        for name, symbol in self._revsetsymbols:
            revset.symbols[name] = symbol
        for name, kw in self._templatekws:
            templatekw.keywords[name] = kw
        for ext, command, wrapper in self._extcommandwrappers:
            if ext not in knownexts:
                e = extensions.find(ext)
                if e is None:
                    raise util.Abort('extension %s not found' % ext)
                knownexts[ext] = e.cmdtable
            extensions.wrapcommand(knownexts[ext], commands, wrapper)
        for c in self._extcallables:
            c(ui)

    def final_reposetup(self, ui, repo):
        """Method to be used as a the extension reposetup

        The following operations belong here:

        - All hooks but pre-* and post-*
        - Modify configuration variables
        - Changes to repo.__class__, repo.dirstate.__class__
        """
        for c in self._repocallables:
            c(ui, repo)

    def uisetup(self, call):
        """Decorated function will be executed during uisetup

        example::

            @eh.uisetup
            def setupbabar(ui):
                print 'this is uisetup!'
        """
        self._uicallables.append(call)
        return call

    def extsetup(self, call):
        """Decorated function will be executed during extsetup

        example::

            @eh.extsetup
            def setupcelestine(ui):
                print 'this is extsetup!'
        """
        self._uicallables.append(call)
        return call

    def reposetup(self, call):
        """Decorated function will be executed during reposetup

        example::

            @eh.reposetup
            def setupzephir(ui, repo):
                print 'this is reposetup!'
        """
        self._repocallables.append(call)
        return call

    def revset(self, symbolname):
        """Decorated function is a revset symbol

        The name of the symbol must be given as the decorator argument.
        The symbol is added during `extsetup`.

        example::

            @eh.revset('hidden')
            def revsetbabar(repo, subset, x):
                args = revset.getargs(x, 0, 0, 'babar accept no argument')
                return [r for r in subset if 'babar' in repo[r].description()]
        """
        def dec(symbol):
            self._revsetsymbols.append((symbolname, symbol))
            return symbol
        return dec


    def templatekw(self, keywordname):
        """Decorated function is a revset keyword

        The name of the keyword must be given as the decorator argument.
        The symbol is added during `extsetup`.

        example::

            @eh.templatekw('babar')
            def kwbabar(ctx):
                return 'babar'
        """
        def dec(keyword):
            self._templatekws.append((keywordname, keyword))
            return keyword
        return dec

    def wrapcommand(self, command, extension=None):
        """Decorated function is a command wrapper

        The name of the command must be given as the decorator argument.
        The wrapping is installed during `uisetup`.

        If the second option `extension` argument is provided, the wrapping
        will be applied in the extension commandtable. This argument must be a
        string that will be searched using `extension.find` if not found and
        Abort error is raised. If the wrapping applies to an extension, it is
        installed during `extsetup`

        example::

            @eh.wrapcommand('summary')
            def wrapsummary(orig, ui, repo, *args, **kwargs):
                ui.note('Barry!')
                return orig(ui, repo, *args, **kwargs)

        """
        def dec(wrapper):
            if extension is None:
                self._commandwrappers.append((command, wrapper))
            else:
                self._extcommandwrappers.append((extension, command, wrapper))
            return wrapper
        return dec

    def wrapfunction(self, container, funcname):
        """Decorated function is a function wrapper

        This function takes two arguments, the container and the name of the
        function to wrap. The wrapping is performed during `uisetup`.
        (there is no extension support)

        example::

            @eh.function(discovery, 'checkheads')
            def wrapfunction(orig, *args, **kwargs):
                ui.note('His head smashed in and his heart cut out')
                return orig(*args, **kwargs)
        """
        def dec(wrapper):
            self._functionwrappers.append((container, funcname, wrapper))
            return wrapper
        return dec

    def addattr(self, container, funcname):
        """Decorated function is to be added to the container

        This function takes two arguments, the container and the name of the
        function to wrap. The wrapping is performed during `uisetup`.

        example::

            @eh.function(context.changectx, 'babar')
            def babar(ctx):
                return 'babar' in ctx.description
        """
        def dec(func):
            self._duckpunchers.append((container, funcname, func))
            return func
        return dec

eh = exthelper()
uisetup = eh.final_uisetup
extsetup = eh.final_extsetup
reposetup = eh.final_reposetup

#####################################################################
### Obsolescence Caching Logic                                    ###
#####################################################################

# Obsolescence related logic can be very slow if we don't have efficient cache.
#
# This section implements a cache mechanism that did not make it into core for
# time reason. It store meaningful set of revision related to obsolescence
# (obsolete, unstabletble ...
#
# Here is:
#
# - Computation of meaningful set,
# - Cache access logic,
# - Cache invalidation logic,
# - revset and ctx using this cache.
#


### Computation of meaningful set
#
# Most set can be computed with "simple" revset.

#: { set name -> function to compute this set } mapping
#:   function take a single "repo" argument.
#:
#: Use the `cachefor` decorator to register new cache function
cachefuncs = {}
def cachefor(name):
    """Decorator to register a function as computing the cache for a set"""
    def decorator(func):
        assert name not in cachefuncs
        cachefuncs[name] = func
        return func
    return decorator

@cachefor('obsolete')
def _computeobsoleteset(repo):
    """the set of obsolete revisions"""
    obs = set()
    nm = repo.changelog.nodemap
    for prec in repo.obsstore.precursors:
        rev = nm.get(prec)
        if rev is not None:
            obs.add(rev)
    return set(repo.revs('%ld - public()', obs))

@cachefor('unstable')
def _computeunstableset(repo):
    """the set of non obsolete revisions with obsolete parents"""
    return set(repo.revs('(obsolete()::) - obsolete()'))

@cachefor('suspended')
def _computesuspendedset(repo):
    """the set of obsolete parents with non obsolete descendants"""
    return set(repo.revs('obsolete() and obsolete()::unstable()'))

@cachefor('extinct')
def _computeextinctset(repo):
    """the set of obsolete parents without non obsolete descendants"""
    return set(repo.revs('obsolete() - obsolete()::unstable()'))

@eh.wrapfunction(obsolete.obsstore, '__init__')
def _initobsstorecache(orig, obsstore, *args, **kwargs):
    """add a cache attribute to obsstore"""
    obsstore.caches = {}
    return orig(obsstore, *args, **kwargs)

### Cache access

def getobscache(repo, name):
    """Return the set of revision that belong to the <name> set

    Such access may compute the set and cache it for future use"""
    if not repo.obsstore:
        return ()
    if name not in repo.obsstore.caches:
        repo.obsstore.caches[name] = cachefuncs[name](repo)
    return repo.obsstore.caches[name]

### Cache clean up
#
# To be simple we need to invalidate obsolescence cache when:
#
# - new changeset is added:
# - public phase is changed
# - obsolescence marker are added
# - strip is used a repo


def clearobscaches(repo):
    """Remove all obsolescence related cache from a repo

    This remove all cache in obsstore is the obsstore already exist on the
    repo.

    (We could be smarter here)"""
    if 'obsstore' in repo._filecache:
        repo.obsstore.caches.clear()

@eh.wrapfunction(localrepo.localrepository, 'addchangegroup')  # new changeset
@eh.wrapfunction(phases, 'retractboundary')  # phase movement
@eh.wrapfunction(phases, 'advanceboundary')  # phase movement
@eh.wrapfunction(localrepo.localrepository, 'destroyed')  # strip
def wrapclearcache(orig, repo, *args, **kwargs):
    try:
        return orig(repo, *args, **kwargs)
    finally:
        # we are a bit wide here
        # we could restrict to:
        # advanceboundary + phase==public
        # retractboundary + phase==draft
        clearobscaches(repo)

@eh.wrapfunction(obsolete.obsstore, 'add')  # new marker
def clearonadd(orig, obsstore, *args, **kwargs):
    try:
        return orig(obsstore, *args, **kwargs)
    finally:
        obsstore.caches.clear()

### Use the case
# Function in core that could benefic from the cache are overwritten by cache using version

# changectx method

@eh.addattr(context.changectx, 'unstable')
def unstable(ctx):
    """is the changeset unstable (have obsolete ancestor)"""
    if ctx.node() is None:
        return False
    return ctx.rev() in getobscache(ctx._repo, 'unstable')


@eh.addattr(context.changectx, 'extinct')
def extinct(ctx):
    """is the changeset extinct by other"""
    if ctx.node() is None:
        return False
    return ctx.rev() in getobscache(ctx._repo, 'extinct')

# revset

@eh.revset('obsolete')
def revsetobsolete(repo, subset, x):
    """``obsolete()``
    Changeset is obsolete.
    """
    args = revset.getargs(x, 0, 0, 'obsolete takes no argument')
    obsoletes = getobscache(repo, 'obsolete')
    return [r for r in subset if r in obsoletes]

@eh.revset('unstable')
def revsetunstable(repo, subset, x):
    """``unstable()``
    Unstable changesets are non-obsolete with obsolete ancestors.
    """
    args = revset.getargs(x, 0, 0, 'unstable takes no arguments')
    unstables = getobscache(repo, 'unstable')
    return [r for r in subset if r in unstables]

@eh.revset('extinct')
def revsetextinct(repo, subset, x):
    """``extinct()``
    Obsolete changesets with obsolete descendants only.
    """
    args = revset.getargs(x, 0, 0, 'extinct takes no arguments')
    extincts = getobscache(repo, 'extinct')
    return [r for r in subset if r in extincts]

#####################################################################
### Complete troubles computation logic                           ###
#####################################################################

# there is two kind of trouble not handled by core right now:
# - latecomer: (successors for public changeset)
# - conflicting: (two changeset try to succeed to the same precursors)
#
# This section add support for those two addition trouble
#
# - Cache computation
# - revset and ctx method
# - push warning

### Cache computation
latediff = 1  # flag to prevent taking late comer fix into account

@cachefor('latecomer')
def _computelatecomerset(repo):
    """the set of rev trying to obsolete public revision"""
    candidates = _allsuccessors(repo, repo.revs('public()'),
                                                haltonflags=latediff)
    query = '%ld - obsolete() - public()'
    return set(repo.revs(query, candidates))

@cachefor('conflicting')
def _computeconflictingset(repo):
    """the set of rev trying to obsolete public revision"""
    conflicting = set()
    obsstore = repo.obsstore
    newermap = {}
    for ctx in repo.set('(not public()) - obsolete()'):
        prec = obsstore.successors.get(ctx.node(), ())
        toprocess = set(prec)
        while toprocess:
            prec = toprocess.pop()[0]
            if prec not in newermap:
                newermap[prec] = newerversion(repo, prec)
            newer = [n for n in newermap[prec] if n] # filter kill
            if len(newer) > 1:
                conflicting.add(ctx.rev())
                break
        toprocess.update(obsstore.successors.get(prec, ()))
    return conflicting

### changectx method

@eh.addattr(context.changectx, 'latecomer')
def latecomer(ctx):
    """is the changeset latecomer (Try to succeed to public change)"""
    if ctx.node() is None:
        return False
    return ctx.rev() in getobscache(ctx._repo, 'latecomer')

@eh.addattr(context.changectx, 'conflicting')
def conflicting(ctx):
    """is the changeset conflicting (Try to succeed to public change)"""
    if ctx.node() is None:
        return False
    return ctx.rev() in getobscache(ctx._repo, 'conflicting')

### revset symbol

@eh.revset('latecomer')
def revsetlatecomer(repo, subset, x):
    """``latecomer()``
    Changesets marked as successors of public changesets.
    """
    args = revset.getargs(x, 0, 0, 'latecomer takes no arguments')
    lates = getobscache(repo, 'latecomer')
    return [r for r in subset if r in lates]

@eh.revset('conflicting')
def revsetconflicting(repo, subset, x):
    """``conflicting()``
    Changesets marked as successors of a same changeset.
    """
    args = revset.getargs(x, 0, 0, 'conflicting takes no arguments')
    conf = getobscache(repo, 'conflicting')
    return [r for r in subset if r in conf]


### Discovery wrapping

@eh.wrapfunction(discovery, 'checkheads')
def wrapcheckheads(orig, repo, remote, outgoing, *args, **kwargs):
    """wrap mercurial.discovery.checkheads

    * prevent latecomer and unstable to be pushed
    """
    # do not push instability
    for h in outgoing.missingheads:
        # Checking heads is enough, obsolete descendants are either
        # obsolete or unstable.
        ctx = repo[h]
        if ctx.latecomer():
            raise util.Abort(_("push includes a latecomer changeset: %s!")
                             % ctx)
        if ctx.conflicting():
            raise util.Abort(_("push includes a conflicting changeset: %s!")
                             % ctx)
    return orig(repo, remote, outgoing, *args, **kwargs)

#####################################################################
### Filter extinct changeset from common operation                ###
#####################################################################

@eh.wrapfunction(merge, 'update')
def wrapmergeupdate(orig, repo, node, *args, **kwargs):
    """ensure we don't automatically update on hidden changeset"""
    if node is None:
        # tip of current branch
        branch = repo[None].branch()
        node = repo.revs('last((.:: and branch(%s)) - hidden())', branch)[0]
    return orig(repo, node, *args, **kwargs)

@eh.wrapfunction(localrepo.localrepository, 'branchtip')
def obsbranchtip(orig, repo, branch):
    """ensure "stable" reference does not end on a hidden changeset"""
    result = ()
    heads = repo.branchmap().get(branch, ())
    if heads:
        result = list(repo.set('last(heads(branch(%n) - hidden()))', heads[0]))
    if not result:
        raise error.RepoLookupError(_("unknown branch '%s'") % branch)
    return result[0].node()


#####################################################################
### Additional Utilities                                          ###
#####################################################################

# This section contains a lot of small utility function and method

# - Function to create markers
# - useful alias pstatus and pdiff (should probably go in evolve)
# - "troubles" method on changectx
# - function to travel throught the obsolescence graph
# - function to find useful changeset to stabilize

### Marker Create

def createmarkers(repo, relations, metadata=None, flag=0):
    """Add obsolete markers between changeset in a repo

    <relations> must be an iterable of (<old>, (<new>, ...)) tuple.
    `old` and `news` are changectx.

    Current user and date are used except if specified otherwise in the
    metadata attribute.

    /!\ assume the repo have been locked by the user /!\
    """
    # prepare metadata
    if metadata is None:
        metadata = {}
    if 'date' not in metadata:
        metadata['date'] = '%i %i' % util.makedate()
    if 'user' not in metadata:
        metadata['user'] = repo.ui.username()
    # check future marker
    tr = repo.transaction('add-obsolescence-marker')
    try:
        for prec, sucs in relations:
            if not prec.mutable():
                raise util.Abort("Cannot obsolete immutable changeset: %s" % prec)
            nprec = prec.node()
            nsucs = tuple(s.node() for s in sucs)
            if nprec in nsucs:
                raise util.Abort("Changeset %s cannot obsolete himself" % prec)
            repo.obsstore.create(tr, nprec, nsucs, flag, metadata)
            clearobscaches(repo)
        tr.close()
    finally:
        tr.release()


### Useful alias

@eh.uisetup
def _installalias(ui):
    if ui.config('alias', 'pstatus', None) is None:
        ui.setconfig('alias', 'pstatus', 'status --rev .^')
    if ui.config('alias', 'pdiff', None) is None:
        ui.setconfig('alias', 'pdiff', 'diff --rev .^')

# - "troubles" method on changectx

@eh.addattr(context.changectx, 'troubles')
def troubles(ctx):
    """Return a tuple listing all the troubles that affect a changeset

    Troubles may be "unstable", "latecomer" or "conflicting".
    """
    troubles = []
    if ctx.unstable():
        troubles.append('unstable')
    if ctx.latecomer():
        troubles.append('latecomer')
    if ctx.conflicting():
        troubles.append('conflicting')
    return tuple(troubles)

### Troubled revset symbol

@eh.revset('troubled')
def revsetlatecomer(repo, subset, x):
    """``troubled()``
    Changesets with troubles.
    """
    _ = revset.getargs(x, 0, 0, 'troubled takes no arguments')
    return list(repo.revs('%ld and (unstable() + latecomer() + conflicting())',
                          subset))


### Obsolescence graph

# XXX SOME MAJOR CLEAN UP TO DO HERE XXX

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 _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()
    for p in seen:
        pr = nm.get(p)
        if pr is not None:
            cs.add(pr)
    return cs

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, haltonflags=0):  # XXX we need a better naming
    """transitive successors of a subset

    haltonflags allows to provide flags which prevent the evaluation of a
    marker.  """
    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, ()):
            if mark[2] & haltonflags:
                continue
            for sub in mark[1]:
                if sub == nullid:
                    continue # should not be here!
                if sub not in seen:
                    seen.add(sub)
                    toproceed.append(sub)
    nm = repo.changelog.nodemap
    cs = set()
    for s in seen:
        sr = nm.get(s)
        if sr is not None:
            cs.add(sr)
    return cs



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
        current = [n for n in current if n != nullid]
        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)


#####################################################################
### Extending revset and template                                 ###
#####################################################################

# this section add several useful revset symbol not yet in core.
# they are subject to changes

### hidden revset is not in core yet

@eh.revset('hidden')
def revsethidden(repo, subset, x):
    """``hidden()``
    Changeset is hidden.
    """
    args = revset.getargs(x, 0, 0, 'hidden takes no argument')
    return [r for r in subset if r in repo.hiddenrevs]

### XXX I'm not sure this revset is useful
@eh.revset('suspended')
def revsetsuspended(repo, subset, x):
    """``suspended()``
    Obsolete changesets with non-obsolete descendants.
    """
    args = revset.getargs(x, 0, 0, 'suspended takes no arguments')
    suspended = getobscache(repo, 'suspended')
    return [r for r in subset if r in suspended]


@eh.revset('precursors')
def revsetprecursors(repo, subset, x):
    """``precursors(set)``
    Immediate precursors of changesets in set.
    """
    s = revset.getset(repo, range(len(repo)), x)
    cs = _precursors(repo, s)
    return [r for r in subset if r in cs]


@eh.revset('allprecursors')
def revsetallprecursors(repo, subset, x):
    """``allprecursors(set)``
    Transitive precursors of changesets in set.
    """
    s = revset.getset(repo, range(len(repo)), x)
    cs = _allprecursors(repo, s)
    return [r for r in subset if r in cs]


@eh.revset('successors')
def revsetsuccessors(repo, subset, x):
    """``successors(set)``
    Immediate successors of changesets in set.
    """
    s = revset.getset(repo, range(len(repo)), x)
    cs = _successors(repo, s)
    return [r for r in subset if r in cs]

@eh.revset('allsuccessors')
def revsetallsuccessors(repo, subset, x):
    """``allsuccessors(set)``
    Transitive successors of changesets in set.
    """
    s = revset.getset(repo, range(len(repo)), x)
    cs = _allsuccessors(repo, s)
    return [r for r in subset if r in cs]

### template keywords
# XXX it does not handle troubles well :-/

@eh.templatekw('obsolete')
def obsoletekw(repo, ctx, templ, **args):
    """:obsolete: String. The obsolescence level of the node, could be
    ``stable``, ``unstable``, ``suspended`` or ``extinct``.
    """
    rev = ctx.rev()
    if ctx.obsolete():
        if ctx.extinct():
            return 'extinct'
        else:
            return 'suspended'
    elif ctx.unstable():
        return 'unstable'
    return 'stable'

#####################################################################
### Various trouble warning                                       ###
#####################################################################

# This section take care of issue warning to the user when troubles appear

@eh.wrapcommand("update")
@eh.wrapcommand("pull")
def wrapmayobsoletewc(origfn, ui, repo, *args, **opts):
    """Warn that the working directory parent is an obsolete changeset"""
    res = origfn(ui, repo, *args, **opts)
    if repo['.'].obsolete():
        ui.warn(_('Working directory parent is obsolete\n'))
    return res

# XXX this could wrap transaction code
# XXX (but this is a bit a layer violation)
@eh.wrapcommand("commit")
@eh.wrapcommand("push")
@eh.wrapcommand("pull")
@eh.wrapcommand("graft")
@eh.wrapcommand("phase")
@eh.wrapcommand("unbundle")
def warnobserrors(orig, ui, repo, *args, **kwargs):
    """display warning is the command resulted in more instable changeset"""
    priorunstables = len(repo.revs('unstable()'))
    priorlatecomers = len(repo.revs('latecomer()'))
    priorconflictings = len(repo.revs('conflicting()'))
    try:
        return orig(ui, repo, *args, **kwargs)
    finally:
        newunstables = len(repo.revs('unstable()')) - priorunstables
        newlatecomers = len(repo.revs('latecomer()')) - priorlatecomers
        newconflictings = len(repo.revs('conflicting()')) - priorconflictings
        if newunstables > 0:
            ui.warn(_('%i new unstables changesets\n') % newunstables)
        if newlatecomers > 0:
            ui.warn(_('%i new latecomers changesets\n') % newlatecomers)
        if newconflictings > 0:
            ui.warn(_('%i new conflictings changesets\n') % newconflictings)

@eh.reposetup
def _repostabilizesetup(ui, repo):
    """Add a hint for "hg stabilize" when troubles make push fails
    """
    if not repo.local():
        return

    opush = repo.push

    class stabilizerrepo(repo.__class__):
        def push(self, remote, *args, **opts):
            """wrapper around pull that pull obsolete relation"""
            try:
                result = opush(remote, *args, **opts)
            except util.Abort, ex:
                hint = _("use 'hg stabilize' to get a stable history "
                         "or --force to ignore warnings")
                if (len(ex.args) >= 1
                    and ex.args[0].startswith('push includes ')
                    and ex.hint is None):
                    ex.hint = hint
                raise
            return result
    repo.__class__ = stabilizerrepo

@eh.wrapcommand("summary")
def obssummary(orig, ui, repo, *args, **kwargs):
    ret = orig(ui, repo, *args, **kwargs)
    nbunstable = len(getobscache(repo, 'unstable'))
    nblatecomer = len(getobscache(repo, 'latecomer'))
    nbconflicting = len(getobscache(repo, 'unstable'))
    if nbunstable:
        ui.write('unstable: %i changesets\n' % nbunstable)
    else:
        ui.note('unstable: 0 changesets\n')
    if nblatecomer:
        ui.write('latecomer: %i changesets\n' % nblatecomer)
    else:
        ui.note('latecomer: 0 changesets\n')
    if nbconflicting:
        ui.write('conflicting: %i changesets\n' % nbconflicting)
    else:
        ui.note('conflicting: 0 changesets\n')
    return ret


#####################################################################
### Core Other extension compat                                   ###
#####################################################################

# This section make official history rewritter create obsolete marker


### commit --amend
# make commit --amend create obsolete marker
#
# The precursor is still strip from the repository.

@eh.wrapfunction(cmdutil, 'amend')
def wrapcmdutilamend(orig, ui, repo, commitfunc, old, *args, **kwargs):
    oldnode = old.node()
    new = orig(ui, repo, commitfunc, old, *args, **kwargs)
    if new != oldnode:
        lock = repo.lock()
        try:
            tr = repo.transaction('post-amend-obst')
            try:
                meta = {
                    'date':  '%i %i' % util.makedate(),
                    'user': ui.username(),
                    }
                repo.obsstore.create(tr, oldnode, [new], 0, meta)
                tr.close()
                clearobscaches(repo)
            finally:
                tr.release()
        finally:
            lock.release()
    return new

### rebase
#
# - ignore obsolete changeset
# - create obsolete marker *instead of* striping

def buildstate(orig, repo, dest, rebaseset, *ags, **kws):
    """wrapper for rebase 's buildstate that exclude obsolete changeset"""

    rebaseset = repo.revs('%ld - extinct()', rebaseset)
    if not rebaseset:
        repo.ui.warn(_('whole rebase set is extinct and ignored.\n'))
        return {}
    root = min(rebaseset)
    if not repo._rebasekeep and not repo[root].mutable():
        raise util.Abort(_("can't rebase immutable changeset %s") % repo[root],
                         hint=_('see hg help phases for details'))
    return orig(repo, dest, rebaseset, *ags, **kws)

def defineparents(orig, repo, rev, target, state, *args, **kwargs):
    rebasestate = getattr(repo, '_rebasestate', None)
    if rebasestate is not None:
        repo._rebasestate = dict(state)
        repo._rebasetarget = target
    return orig(repo, rev, target, state, *args, **kwargs)

def concludenode(orig, repo, rev, p1, *args, **kwargs):
    """wrapper for rebase 's concludenode that set obsolete relation"""
    newrev = orig(repo, rev, p1, *args, **kwargs)
    rebasestate = getattr(repo, '_rebasestate', None)
    if rebasestate is not None:
        if newrev is not None:
            nrev = repo[newrev].rev()
        else:
            nrev = p1
        repo._rebasestate[rev] = nrev
    return newrev

def cmdrebase(orig, ui, repo, *args, **kwargs):

    reallykeep = kwargs.get('keep', False)
    kwargs = dict(kwargs)
    kwargs['keep'] = True
    repo._rebasekeep = reallykeep

    # We want to mark rebased revision as obsolete and set their
    # replacements if any. Doing it in concludenode() prevents
    # aborting the rebase, and is not called with all relevant
    # revisions in --collapse case. Instead, we try to track the
    # rebase state structure by sampling/updating it in
    # defineparents() and concludenode(). The obsolete markers are
    # added from this state after a successful call.
    repo._rebasestate = {}
    repo._rebasetarget = None
    try:
        l = repo.lock()
        try:
            res = orig(ui, repo, *args, **kwargs)
            if not reallykeep:
                # Filter nullmerge or unrebased entries
                repo._rebasestate = dict(p for p in repo._rebasestate.iteritems()
                                         if p[1] >= 0)
                if not res and not kwargs.get('abort') and repo._rebasestate:
                    # Rebased revisions are assumed to be descendants of
                    # targetrev. If a source revision is mapped to targetrev
                    # or to another rebased revision, it must have been
                    # removed.
                    markers = []
                    if kwargs.get('collapse'):
                        # collapse assume revision disapear because they are all
                        # in the created revision
                        newrevs = set(repo._rebasestate.values())
                        newrevs.remove(repo._rebasetarget)
                        if newrevs:
                            # we create new revision.
                            # A single one by --collapse design
                            assert len(newrevs) == 1
                            new = tuple(repo[n] for n in newrevs)
                        else:
                            # every body died. no new changeset created
                            new = (repo[repo._rebasetarget],)
                        for rev, newrev in sorted(repo._rebasestate.items()):
                            markers.append((repo[rev], new))
                    else:
                        # no collapse assume revision disapear because they are
                        # contained in parent
                        for rev, newrev in sorted(repo._rebasestate.items()):
                            markers.append((repo[rev], (repo[newrev],)))
                    createmarkers(repo, markers)
            return res
        finally:
            l.release()
    finally:
        delattr(repo, '_rebasestate')
        delattr(repo, '_rebasetarget')

@eh.extsetup
def _rebasewrapping(ui):
    # warning about more obsolete
    try:
        rebase = extensions.find('rebase')
        if rebase:
            entry = extensions.wrapcommand(rebase.cmdtable, 'rebase', warnobserrors)
            extensions.wrapfunction(rebase, 'buildstate', buildstate)
            extensions.wrapfunction(rebase, 'defineparents', defineparents)
            extensions.wrapfunction(rebase, 'concludenode', concludenode)
            extensions.wrapcommand(rebase.cmdtable, "rebase", cmdrebase)
    except KeyError:
        pass  # rebase not found


#####################################################################
### Older format management                                       ###
#####################################################################

# Code related to detection and management of older legacy format never
# handled by core

import json

@eh.reposetup
def _checkoldobsolete(ui, repo):
    """Detect that a repo still contains some old obsolete format
    """
    if not repo.local():
        return
    for arg in sys.argv:
        if 'debugc' in arg:
            break
    else:
        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.')

def _obsdeserialise(flike):
    """read a file like object serialised with _obsserialise

    this desierialize into a {subject -> objects} mapping

    this was the very first format ever."""
    rels = {}
    for line in flike:
        subhex, objhex = line.split()
        subnode = bin(subhex)
        if subnode == nullid:
            subnode = None
        rels.setdefault( subnode, set()).add(bin(objhex))
    return rels

cmdtable = {}
command = cmdutil.command(cmdtable)
@command('debugconvertobsolete', [], '')
def cmddebugconvertobsolete(ui, repo):
    """import markers from an .hg/obsolete-relations file"""
    cnt = 0
    err = 0
    l = repo.lock()
    some = False
    try:
        unlink = []
        tr = repo.transaction('convert-obsolete')
        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(),
                            }
                        try:
                            store.create(tr, prec, sucs, 0, meta)
                            cnt += 1
                        except ValueError:
                            repo.ui.write_err("invalid old marker line: %s"
                                              % (line))
                            err += 1
                finally:
                    f.close()
                unlink.append(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
                    oldobject = str(oldmark.pop('object'))
                    oldsubjects = [str(s) for s in oldmark.pop('subjects', [])]
                    LOOKUP_ERRORS = (error.RepoLookupError, error.LookupError)
                    if len(oldobject) != 40:
                        try:
                            oldobject = repo[oldobject].node()
                        except LOOKUP_ERRORS:
                            pass
                    if any(len(s) != 40 for s in oldsubjects):
                        try:
                            oldsubjects = [repo[s].node() for s in oldsubjects]
                        except LOOKUP_ERRORS:
                            pass

                    oldmark['date'] = '%i %i' % tuple(oldmark['date'])
                    meta = dict((k.encode('utf-8'), v.encode('utf-8'))
                                 for k, v in oldmark.iteritems())
                    try:
                        succs = [bin(n) for n in oldsubjects]
                        succs = [n for n in succs if n != nullid]
                        store.create(tr, bin(oldobject), succs,
                                     0, meta)
                        cnt += 1
                    except ValueError:
                        repo.ui.write_err("invalid marker %s -> %s\n"
                                     % (oldobject, oldsubjects))
                        err += 1
                unlink.append(repo.sjoin('obsoletemarkers'))
            tr.close()
            for path in unlink:
                util.unlink(path)
        finally:
            tr.release()
    finally:
        del repo._importoldobsolete
        l.release()
    if not some:
            ui.warn('nothing to do\n')
    ui.status('%i obsolete marker converted\n' % cnt)
    if err:
        ui.write_err('%i conversion failed. check you graph!\n' % err)