diff -r 95089805c3fc -r 8945a62f9096 hgext/evolve.py
--- a/hgext/evolve.py	Sun Oct 14 16:23:25 2012 +0200
+++ b/hgext/evolve.py	Tue Oct 23 16:53:11 2012 +0200
@@ -19,6 +19,10 @@
     - improves some aspect of the early implementation in 2.3
 '''
 
+testedwith = '2.3 2.3.1 2.3.2'
+buglink = 'https://bitbucket.org/marmoute/mutable-history/issues'
+
+
 import random
 
 from mercurial import util
@@ -28,7 +32,16 @@
     if not obsolete._enabled:
         obsolete._enabled = True
 except ImportError:
-    raise util.Abort('Obsolete extension requires Mercurial 2.3 (or later)')
+    raise util.Abort('Evolve extension requires Mercurial 2.3 (or later)')
+
+try:
+    getattr(obsolete, 'getrevs') # 2.4 specific
+    raise util.Abort('Your version of Mercurial is too recent for this '
+                     'version of evolve',
+                     hint="upgrade your evolve")
+except AttributeError:
+    pass
+
 
 from mercurial import bookmarks
 from mercurial import cmdutil
@@ -324,7 +337,7 @@
 
 # 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)
+# - divergent: (two changeset try to succeed to the same precursors)
 #
 # This section add support for those two addition trouble
 #
@@ -343,25 +356,25 @@
     query = '%ld - obsolete() - public()'
     return set(repo.revs(query, candidates))
 
-@cachefor('conflicting')
-def _computeconflictingset(repo):
+@cachefor('divergent')
+def _computedivergentset(repo):
     """the set of rev trying to obsolete public revision"""
-    conflicting = set()
+    divergent = set()
     obsstore = repo.obsstore
     newermap = {}
     for ctx in repo.set('(not public()) - obsolete()'):
-        prec = obsstore.successors.get(ctx.node(), ())
-        toprocess = set(prec)
+        mark = obsstore.successors.get(ctx.node(), ())
+        toprocess = set(mark)
         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
+                successorssets(repo, prec, newermap)
+            newer = [n for n in newermap[prec] if n]
             if len(newer) > 1:
-                conflicting.add(ctx.rev())
+                divergent.add(ctx.rev())
                 break
-        toprocess.update(obsstore.successors.get(prec, ()))
-    return conflicting
+            toprocess.update(obsstore.successors.get(prec, ()))
+    return divergent
 
 ### changectx method
 
@@ -373,11 +386,12 @@
     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)"""
+@eh.addattr(context.changectx, 'divergent')
+def divergent(ctx):
+    """is the changeset divergent (Try to succeed to public change)"""
     if ctx.node() is None:
         return False
-    return ctx.rev() in getobscache(ctx._repo, 'conflicting')
+    return ctx.rev() in getobscache(ctx._repo, 'divergent')
 
 ### revset symbol
 
@@ -391,24 +405,17 @@
     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]
-
 @eh.revset('divergent')
 def revsetdivergent(repo, subset, x):
     """``divergent()``
     Changesets marked as successors of a same changeset.
     """
     args = revset.getargs(x, 0, 0, 'divergent takes no arguments')
-    conf = getobscache(repo, 'conflicting')
+    conf = getobscache(repo, 'divergent')
     return [r for r in subset if r in conf]
 
 
+
 ### Discovery wrapping
 
 @eh.wrapfunction(discovery, 'checkheads')
@@ -425,8 +432,8 @@
         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!")
+        if ctx.divergent():
+            raise util.Abort(_("push includes a divergent changeset: %s!")
                              % ctx)
     return orig(repo, remote, outgoing, *args, **kwargs)
 
@@ -498,15 +505,15 @@
 def troubles(ctx):
     """Return a tuple listing all the troubles that affect a changeset
 
-    Troubles may be "unstable", "latecomer" or "conflicting".
+    Troubles may be "unstable", "latecomer" or "divergent".
     """
     troubles = []
     if ctx.unstable():
         troubles.append('unstable')
     if ctx.latecomer():
         troubles.append('latecomer')
-    if ctx.conflicting():
-        troubles.append('conflicting')
+    if ctx.divergent():
+        troubles.append('divergent')
     return tuple(troubles)
 
 ### Troubled revset symbol
@@ -517,7 +524,7 @@
     Changesets with troubles.
     """
     _ = revset.getargs(x, 0, 0, 'troubled takes no arguments')
-    return repo.revs('%ld and (unstable() + latecomer() + conflicting())',
+    return repo.revs('%ld and (unstable() + latecomer() + divergent())',
                      subset)
 
 
@@ -597,29 +604,123 @@
             cs.add(sr)
     return cs
 
+nodemod = node
+def successorssets(repo, initialnode, cache=None):
+    """Return the newer version of an obsolete changeset"""
+
+    # prec -> markers mapping
+    markersfor = repo.obsstore.precursors
+
+    # Stack of node need to know the last successors set
+    toproceed = [initialnode]
+    # set version of toproceed for fast loop detection
+    stackedset = set(toproceed)
+    if cache is None:
+        cache = {}
+    while toproceed:
+        # work on the last node of the stack
+        node = toproceed[-1]
+        if node in cache:
+            # We already have a value for it.
+            # Keep working on something else.
+            stackedset.remove(toproceed.pop())
+        elif node not in markersfor:
+            # The node is not obsolete.
+            # This mean it is its own last successors.
+            if node in repo:
+                # We have a valid last successors.
+                cache[node] = [(node,)]
+            else:
+                # final obsolete version is unknown locally.
+                # Do not count that as a valid successors
+                cache[node] = []
+        else:
+            # <lss> stand for Last Successors Sets
+            # it contains the list of all last successors for the current node.
+            lss = []
+            for mark in markersfor[node]:
+                # <mlss> stand for Marker Last Successors Sets
+                # it contains the list of last successors set introduced by
+                # this marker.
+                mlss = [[]]
+                # iterate over possible multiple successors
+                for suc in mark[1]:
+                    if suc not in cache:
+                        # We do not know the last successors of that yet.
+                        if suc in stackedset:
+                            # Loop detected!
+                            #
+                            # we won't be able to ever compute a proper last
+                            # successors the naive and simple approve is to
+                            # consider it killed
+                            cache[suc] = []
+                        else:
+                            # Add the successor to the stack and break the next
+                            # iteration will work on this successors and the
+                            # algorithm will eventually process the current
+                            # node again.
+                            toproceed.append(suc)
+                            stackedset.add(suc)
+                            break
+                    # if we did not break, we can extend the possible set of
+                    # last successors.
+                    #
+                    # I say "extends" because if the marker have multiple
+                    # successors we have to generate
+                    #
+                    # if successors have multiple successors set (when ther are
+                    # divergent themself), we do a cartesian product of
+                    # possible successors set of already processed successors
+                    # and newly obtains successors set.
+                    newmlss = []
+                    for prefix in mlss:
+                        for suffix in cache[suc]:
+                            newss = list(prefix)
+                            for part in suffix:
+                                # do not duplicated entry in successors set.
+                                # first entry win.
+                                if part not in newss:
+                                    newss.append(part)
+                            newmlss.append(newss)
+                    mlss = newmlss
+                else:
+                    # note: mlss is still empty if the marker was a bare killing
+                    # of this changeset
+                    #
+                    # We extends the list of all possible successors sets with
+                    # successors set continuted by this marker
+                    lss.extend(mlss)
+                    # we use continue here to skip the break right bellow
+                    continue
+                # propagate "nested for" break.
+                # if the nested for exited on break, it did not ran the else
+                # clause and didn't "continue
+                break
+            else:
+                # computation was succesful for *all* marker.
+                # Add computed successors set to the cache
+                # (will be poped from to proceeed) on the new iteration
+                #
+                # We remove successors set that are subset of another one
+                # this fil
+                candsucset = sorted(((len(ss), set(ss), ss) for ss in lss),
+                                    reverse=True)
+                finalsucset = []
+                for cl, cs, css in candsucset:
+                    if not css:
+                        # remove empty successors set
+                        continue
+                    for fs, fss in finalsucset:
+                        if cs.issubset(fs):
+                            break
+                    else:
+                        finalsucset.append((cs, css))
+                finalsucset = [s[1] for s in finalsucset]
+                finalsucset.reverse()
+                cache[node] = finalsucset
+    return cache[initialnode]
 
 
-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)
 
 
 #####################################################################
@@ -724,19 +825,19 @@
     """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()'))
+    priordivergents = len(repo.revs('divergent()'))
     ret = orig(ui, repo, *args, **kwargs)
     # workaround phase stupidity
     phases._filterunknown(ui, repo.changelog, repo._phasecache.phaseroots)
     newunstables = len(repo.revs('unstable()')) - priorunstables
     newlatecomers = len(repo.revs('latecomer()')) - priorlatecomers
-    newconflictings = len(repo.revs('conflicting()')) - priorconflictings
+    newdivergents = len(repo.revs('divergent()')) - priordivergents
     if newunstables > 0:
         ui.warn(_('%i new unstable changesets\n') % newunstables)
     if newlatecomers > 0:
         ui.warn(_('%i new latecomer changesets\n') % newlatecomers)
-    if newconflictings > 0:
-        ui.warn(_('%i new conflicting changesets\n') % newconflictings)
+    if newdivergents > 0:
+        ui.warn(_('%i new divergent changesets\n') % newdivergents)
     return ret
 
 @eh.reposetup
@@ -776,10 +877,10 @@
     ret = orig(ui, repo, *args, **kwargs)
     nbunstable = len(getobscache(repo, 'unstable'))
     nblatecomer = len(getobscache(repo, 'latecomer'))
-    nbconflicting = len(getobscache(repo, 'unstable'))
+    nbdivergent = len(getobscache(repo, 'unstable'))
     write('unstable: %i changesets\n', nbunstable)
     write('latecomer: %i changesets\n', nblatecomer)
-    write('conflicting: %i changesets\n', nbconflicting)
+    write('divergent: %i changesets\n', nbdivergent)
     return ret
 
 
@@ -998,7 +1099,7 @@
 
     - rebase unstable changeset to make it stable again,
     - create proper diff from latecomer changeset,
-    - merge conflicting changeset.
+    - merge divergent changeset.
 
     By default, take the first troubles changeset that looks relevant.
 
@@ -1008,7 +1109,7 @@
       working directory parent revision or one of its descendants and rebase
       it.
 
-    - For conflicting this mean "." if applicable.
+    - For divergent this mean "." if applicable.
 
     With --any, evolve pick any troubled changeset to solve
 
@@ -1041,8 +1142,8 @@
         return _solveunstable(ui, repo, tr, opts['dry_run'])
     elif 'latecomer' in troubles:
         return _solvelatecomer(ui, repo, tr, opts['dry_run'])
-    elif 'conflicting' in troubles:
-        return _solveconflicting(ui, repo, tr, opts['dry_run'])
+    elif 'divergent' in troubles:
+        return _solvedivergent(ui, repo, tr, opts['dry_run'])
     else:
         assert False  # WHAT? unknown troubles
 
@@ -1051,14 +1152,14 @@
     tr = _stabilizableunstable(repo, repo['.'])
     if tr is None:
         wdp = repo['.']
-        if 'conflicting' in wdp.troubles():
+        if 'divergent' in wdp.troubles():
             tr = wdp
     if tr is None and pickany:
         troubled = list(repo.set('unstable()'))
         if not troubled:
             troubled = list(repo.set('latecomer()'))
         if not troubled:
-            troubled = list(repo.set('conflicting()'))
+            troubled = list(repo.set('divergent()'))
         if troubled:
             tr = troubled[0]
 
@@ -1089,13 +1190,13 @@
     if not obs.obsolete():
         obs = orig.parents()[1]
     assert obs.obsolete()
-    newer = newerversion(repo, obs.node())
+    newer = successorssets(repo, obs.node())
     # search of a parent which is not killed
-    while newer == [()]:
+    while not newer or newer == [()]:
         ui.debug("stabilize target %s is plain dead,"
                  " trying to stabilize on its parent")
         obs = obs.parents()[0]
-        newer = newerversion(repo, obs.node())
+        newer = successorssets(repo, obs.node())
     if len(newer) > 1:
         ui.write_err(_("conflict rewriting. can't choose destination\n"))
         return 2
@@ -1231,22 +1332,22 @@
     finally:
         wlock.release()
 
-def _solveconflicting(ui, repo, conflicting, dryrun=False):
-    base, others = conflictingdata(conflicting)
+def _solvedivergent(ui, repo, divergent, dryrun=False):
+    base, others = divergentdata(divergent)
     if len(others) > 1:
         raise util.Abort("We do not handle split yet")
     other = others[0]
-    if conflicting.phase() <= phases.public:
+    if divergent.phase() <= phases.public:
         raise util.Abort("We can't resolve this conflict from the public side")
     if len(other.parents()) > 1:
-        raise util.Abort("conflicting changeset can't be a merge (yet)")
-    if other.p1() not in conflicting.parents():
+        raise util.Abort("divergent changeset can't be a merge (yet)")
+    if other.p1() not in divergent.parents():
         raise util.Abort("parents are not common (not handled yet)")
 
     displayer = cmdutil.show_changeset(ui, repo, {'template': shorttemplate})
     ui.status(_('merge:'))
     if not ui.quiet:
-        displayer.show(conflicting)
+        displayer.show(divergent)
     ui.status(_('with: '))
     if not ui.quiet:
         displayer.show(other)
@@ -1254,23 +1355,23 @@
     if not ui.quiet:
         displayer.show(base)
     if dryrun:
-        ui.write('hg update -c %s &&\n' % conflicting)
+        ui.write('hg update -c %s &&\n' % divergent)
         ui.write('hg merge %s &&\n' % other)
         ui.write('hg commit -m "auto merge resolving conflict between '
-                 '%s and %s"&&\n' % (conflicting, other))
+                 '%s and %s"&&\n' % (divergent, other))
         ui.write('hg up -C %s &&\n' % base)
         ui.write('hg revert --all --rev tip &&\n')
         ui.write('hg commit -m "`hg log -r %s --template={desc}`";\n'
-                 % conflicting)
+                 % divergent)
         return
     wlock = lock = None
     try:
         wlock = repo.wlock()
         lock = repo.lock()
-        if conflicting not in repo[None].parents():
+        if divergent not in repo[None].parents():
             repo.ui.status(_('updating to "local" conflict\n'))
-            hg.update(repo, conflicting.rev())
-        repo.ui.note(_('merging conflicting changeset\n'))
+            hg.update(repo, divergent.rev())
+        repo.ui.note(_('merging divergent changeset\n'))
         stats = merge.update(repo,
                              other.node(),
                              branchmerge=True,
@@ -1291,13 +1392,13 @@
 /!\ * hg ci -m "same message as the amended changeset" => new cset Y
 /!\ * hg kill -n Y W Z
 """)
-        tr = repo.transaction('stabilize-conflicting')
+        tr = repo.transaction('stabilize-divergent')
         try:
-            repo.dirstate.setparents(conflicting.node(), node.nullid)
+            repo.dirstate.setparents(divergent.node(), node.nullid)
             oldlen = len(repo)
             amend(ui, repo)
             if oldlen == len(repo):
-                new = conflicting
+                new = divergent
                 # no changes
             else:
                 new = repo['.']
@@ -1310,7 +1411,7 @@
         lockmod.release(lock, wlock)
 
 
-def conflictingdata(ctx):
+def divergentdata(ctx):
     """return base, other part of a conflict
 
     This only return the first one.
@@ -1318,7 +1419,7 @@
     XXX this woobly function won't survive XXX
     """
     for base in ctx._repo.set('reverse(precursors(%d))', ctx):
-        newer = newerversion(ctx._repo, base.node())
+        newer = successorssets(ctx._repo, base.node())
         # drop filter and solution including the original ctx
         newer = [n for n in newer if n and ctx.node() not in n]
         if newer:
@@ -1778,6 +1879,60 @@
     finally:
         lockmod.release(lock, wlock)
 
+if 'debugsuccessorssets' not in commands.table:
+
+    @command('debugsuccessorssets',
+        [],
+        _('[REV]'))
+    def debugsuccessorssets(ui, repo, *revs):
+        """show set of successors for revision
+
+        Successors set of changeset A are a consistent group of revision that
+        succeed to A. Successors set contains non-obsolete changeset only.
+
+        In most case a changeset A have zero (changeset pruned) or a single
+        successors set that contains a single successors (changeset A replacement
+        by A')
+
+        But splitted changeset will result with successors set containing more than
+        a single element. Divergent rewritting will result in multiple successor
+        set.
+
+        result is displayed as follows::
+
+            <rev1>
+                <successors-1A>
+            <rev2>
+                <successors-2A>
+                <successors-2B1> <successors-2B1> <successors-2B1>
+
+        here rev2 have two possible successors sets. One hold three elements.
+
+        add --debug if you want full size node id.
+        """
+        cache = {}
+        s = str
+        if ui.debug:
+            def s(ctx):
+                return ctx.hex()
+        for rev in scmutil.revrange(repo, revs):
+            ctx = repo[rev]
+            if ui.debug():
+                ui.write('%s\n'% ctx.hex())
+                s = node.hex
+            else:
+                ui.write('%s\n'% ctx)
+                s = node.short
+            for ss in successorssets(repo, ctx.node(), cache):
+                if ss:
+                    ui.write('    ')
+                    ui.write(s(ss[0]))
+                    for n in ss[1:]:
+                        ui.write(' ')
+                        ui.write(s(n))
+                ui.write('\n')
+        pass
+
 
 @eh.wrapcommand('graft')
 def graftwrapper(orig, ui, repo, *revs, **kwargs):