--- a/hgext/evolve.py	Tue Oct 23 15:44:24 2012 +0200
+++ b/hgext/evolve.py	Tue Oct 23 16:36:29 2012 +0200
@@ -537,17 +537,17 @@
     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:
                 divergent.add(ctx.rev())
                 break
-        toprocess.update(obsstore.successors.get(prec, ()))
+            toprocess.update(obsstore.successors.get(prec, ()))
     return divergent
 
 ### changectx method
@@ -815,6 +815,122 @@
             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):
@@ -1681,7 +1797,7 @@
     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:
@@ -2141,6 +2257,60 @@
     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):

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-obsolete-divergent.t	Tue Oct 23 16:36:29 2012 +0200
@@ -0,0 +1,439 @@
+Test file decicated to testing the divergent troubles from obsolete changeset.
+
+This is the most complexe troubles from far so we isolate it in a dedicated
+file.
+
+Enable obsolete
+
+  $ cat >> $HGRCPATH << EOF
+  > [ui]
+  > logtemplate = {rev}:{node|short} {desc}\n
+  > [alias]
+  > debugobsolete = debugobsolete -d '0 0'
+  > [phases]
+  > publish=False
+  > [extensions]
+  > rebase=
+  > EOF
+  $ echo "evolve=$(echo $(dirname $TESTDIR))/hgext/evolve.py" >> $HGRCPATH
+
+
+  $ mkcommit() {
+  >    echo "$1" > "$1"
+  >    hg add "$1"
+  >    hg ci -m "$1"
+  > }
+  $ getid() {
+  >    hg id --debug -ir "desc('$1')"
+  > }
+
+setup repo
+
+  $ hg init reference
+  $ cd reference
+  $ mkcommit base
+  $ mkcommit A_0
+  $ hg up 0
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mkcommit A_1
+  created new head
+  $ hg up 0
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mkcommit A_2
+  created new head
+  $ hg up 0
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ cd ..
+
+
+  $ newcase() {
+  >    hg clone -u 0 -q reference $1
+  >    cd $1
+  > }
+
+direct divergence
+-----------------
+
+A_1 have two direct and divergent successors A_1 and A_1
+
+  $ newcase direct
+  $ hg debugobsolete `getid A_0` `getid A_1`
+  $ hg debugobsolete `getid A_0` `getid A_2`
+  $ hg log -G --hidden
+  o  3:392fd25390da A_2
+  |
+  | o  2:82623d38b9ba A_1
+  |/
+  | x  1:007dc284c1f8 A_0
+  |/
+  @  0:d20a80d4def3 base
+  
+  $ hg debugsuccessorssets 'all()'
+  d20a80d4def3
+      d20a80d4def3
+  007dc284c1f8
+      392fd25390da
+      82623d38b9ba
+  82623d38b9ba
+      82623d38b9ba
+  392fd25390da
+      392fd25390da
+  $ hg log -r 'divergent()'
+  2:82623d38b9ba A_1
+  3:392fd25390da A_2
+
+check that mercurial refuse to push
+
+  $ hg init ../other
+  $ hg push ../other
+  pushing to ../other
+  searching for changes
+  abort: push includes a divergent changeset: 82623d38b9ba!
+  (use 'hg evolve' to get a stable history or --force to ignore warnings)
+  [255]
+
+  $ cd ..
+
+
+indirect divergence with known changeset
+-------------------------------------------
+
+  $ newcase indirect_known
+  $ hg debugobsolete `getid A_0` `getid A_1`
+  $ hg debugobsolete `getid A_0` `getid A_2`
+  $ mkcommit A_3
+  created new head
+  $ hg debugobsolete `getid A_2` `getid A_3`
+  $ hg log -G --hidden
+  @  4:01f36c5a8fda A_3
+  |
+  | x  3:392fd25390da A_2
+  |/
+  | o  2:82623d38b9ba A_1
+  |/
+  | x  1:007dc284c1f8 A_0
+  |/
+  o  0:d20a80d4def3 base
+  
+  $ hg debugsuccessorssets 'all()'
+  d20a80d4def3
+      d20a80d4def3
+  007dc284c1f8
+      01f36c5a8fda
+      82623d38b9ba
+  82623d38b9ba
+      82623d38b9ba
+  392fd25390da
+      01f36c5a8fda
+  01f36c5a8fda
+      01f36c5a8fda
+  $ hg log -r 'divergent()'
+  2:82623d38b9ba A_1
+  4:01f36c5a8fda A_3
+  $ cd ..
+
+
+indirect divergence with known changeset
+-------------------------------------------
+
+  $ newcase indirect_unknown
+  $ hg debugobsolete `getid A_0` aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+  $ hg debugobsolete aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa `getid A_1`
+  $ hg debugobsolete `getid A_0` `getid A_2`
+  $ hg log -G --hidden
+  o  3:392fd25390da A_2
+  |
+  | o  2:82623d38b9ba A_1
+  |/
+  | x  1:007dc284c1f8 A_0
+  |/
+  @  0:d20a80d4def3 base
+  
+  $ hg debugsuccessorssets 'all()'
+  d20a80d4def3
+      d20a80d4def3
+  007dc284c1f8
+      392fd25390da
+      82623d38b9ba
+  82623d38b9ba
+      82623d38b9ba
+  392fd25390da
+      392fd25390da
+  $ hg log -r 'divergent()'
+  2:82623d38b9ba A_1
+  3:392fd25390da A_2
+  $ cd ..
+
+do not take unknown node in account if they are final
+-----------------------------------------------------
+
+  $ newcase final-unknown
+  $ hg debugobsolete `getid A_0` `getid A_1`
+  $ hg debugobsolete `getid A_1` `getid A_2`
+  $ hg debugobsolete `getid A_0` bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+  $ hg debugobsolete bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb cccccccccccccccccccccccccccccccccccccccc
+  $ hg debugobsolete `getid A_1` dddddddddddddddddddddddddddddddddddddddd
+
+  $ hg debugsuccessorssets 'desc('A_0')'
+  007dc284c1f8
+      392fd25390da
+
+  $ cd ..
+
+divergence that converge again is not divergence anymore
+-----------------------------------------------------
+
+  $ newcase converged_divergence
+  $ hg debugobsolete `getid A_0` `getid A_1`
+  $ hg debugobsolete `getid A_0` `getid A_2`
+  $ mkcommit A_3
+  created new head
+  $ hg debugobsolete `getid A_1` `getid A_3`
+  $ hg debugobsolete `getid A_2` `getid A_3`
+  $ hg log -G --hidden
+  @  4:01f36c5a8fda A_3
+  |
+  | x  3:392fd25390da A_2
+  |/
+  | x  2:82623d38b9ba A_1
+  |/
+  | x  1:007dc284c1f8 A_0
+  |/
+  o  0:d20a80d4def3 base
+  
+  $ hg debugsuccessorssets 'all()'
+  d20a80d4def3
+      d20a80d4def3
+  007dc284c1f8
+      01f36c5a8fda
+  82623d38b9ba
+      01f36c5a8fda
+  392fd25390da
+      01f36c5a8fda
+  01f36c5a8fda
+      01f36c5a8fda
+  $ hg log -r 'divergent()'
+  $ cd ..
+
+split is not divergences
+-----------------------------
+
+  $ newcase split
+  $ hg debugobsolete `getid A_0` `getid A_1` `getid A_2`
+  $ hg log -G --hidden
+  o  3:392fd25390da A_2
+  |
+  | o  2:82623d38b9ba A_1
+  |/
+  | x  1:007dc284c1f8 A_0
+  |/
+  @  0:d20a80d4def3 base
+  
+  $ hg debugsuccessorssets 'all()'
+  d20a80d4def3
+      d20a80d4def3
+  007dc284c1f8
+      82623d38b9ba 392fd25390da
+  82623d38b9ba
+      82623d38b9ba
+  392fd25390da
+      392fd25390da
+  $ hg log -r 'divergent()'
+
+Even when subsequente rewriting happen
+
+  $ mkcommit A_3
+  created new head
+  $ hg debugobsolete `getid A_1` `getid A_3`
+  $ hg up 0
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mkcommit A_4
+  created new head
+  $ hg debugobsolete `getid A_2` `getid A_4`
+  $ hg up 0
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mkcommit A_5
+  created new head
+  $ hg debugobsolete `getid A_4` `getid A_5`
+  $ hg log -G --hidden
+  @  6:e442cfc57690 A_5
+  |
+  | x  5:6a411f0d7a0a A_4
+  |/
+  | o  4:01f36c5a8fda A_3
+  |/
+  | x  3:392fd25390da A_2
+  |/
+  | x  2:82623d38b9ba A_1
+  |/
+  | x  1:007dc284c1f8 A_0
+  |/
+  o  0:d20a80d4def3 base
+  
+  $ hg debugsuccessorssets 'all()'
+  d20a80d4def3
+      d20a80d4def3
+  007dc284c1f8
+      01f36c5a8fda e442cfc57690
+  82623d38b9ba
+      01f36c5a8fda
+  392fd25390da
+      e442cfc57690
+  01f36c5a8fda
+      01f36c5a8fda
+  6a411f0d7a0a
+      e442cfc57690
+  e442cfc57690
+      e442cfc57690
+  $ hg log -r 'divergent()'
+
+Check more complexe obsolescence graft (with divergence)
+
+  $ mkcommit B_0; hg up 0
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ hg debugobsolete `getid B_0` `getid A_2`
+  $ mkcommit A_7; hg up 0
+  created new head
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ mkcommit A_8; hg up 0
+  created new head
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg debugobsolete `getid A_5` `getid A_7` `getid A_8`
+  $ mkcommit A_9; hg up 0
+  created new head
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg debugobsolete `getid A_5` `getid A_9`
+  $ hg log -G --hidden
+  o  10:bed64f5d2f5a A_9
+  |
+  | o  9:14608b260df8 A_8
+  |/
+  | o  8:7ae126973a96 A_7
+  |/
+  | x  7:3750ebee865d B_0
+  | |
+  | x  6:e442cfc57690 A_5
+  |/
+  | x  5:6a411f0d7a0a A_4
+  |/
+  | o  4:01f36c5a8fda A_3
+  |/
+  | x  3:392fd25390da A_2
+  |/
+  | x  2:82623d38b9ba A_1
+  |/
+  | x  1:007dc284c1f8 A_0
+  |/
+  @  0:d20a80d4def3 base
+  
+  $ hg debugsuccessorssets 'all()'
+  d20a80d4def3
+      d20a80d4def3
+  007dc284c1f8
+      01f36c5a8fda bed64f5d2f5a
+      01f36c5a8fda 7ae126973a96 14608b260df8
+  82623d38b9ba
+      01f36c5a8fda
+  392fd25390da
+      bed64f5d2f5a
+      7ae126973a96 14608b260df8
+  01f36c5a8fda
+      01f36c5a8fda
+  6a411f0d7a0a
+      bed64f5d2f5a
+      7ae126973a96 14608b260df8
+  e442cfc57690
+      bed64f5d2f5a
+      7ae126973a96 14608b260df8
+  3750ebee865d
+      bed64f5d2f5a
+      7ae126973a96 14608b260df8
+  7ae126973a96
+      7ae126973a96
+  14608b260df8
+      14608b260df8
+  bed64f5d2f5a
+      bed64f5d2f5a
+  $ hg log -r 'divergent()'
+  4:01f36c5a8fda A_3
+  8:7ae126973a96 A_7
+  9:14608b260df8 A_8
+  10:bed64f5d2f5a A_9
+
+fix the divergence
+
+  $ mkcommit A_A; hg up 0
+  created new head
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg debugobsolete `getid A_9` `getid A_A`
+  $ hg debugobsolete `getid A_7` `getid A_A`
+  $ hg debugobsolete `getid A_8` `getid A_A`
+  $ hg log -G --hidden
+  o  11:a139f71be9da A_A
+  |
+  | x  10:bed64f5d2f5a A_9
+  |/
+  | x  9:14608b260df8 A_8
+  |/
+  | x  8:7ae126973a96 A_7
+  |/
+  | x  7:3750ebee865d B_0
+  | |
+  | x  6:e442cfc57690 A_5
+  |/
+  | x  5:6a411f0d7a0a A_4
+  |/
+  | o  4:01f36c5a8fda A_3
+  |/
+  | x  3:392fd25390da A_2
+  |/
+  | x  2:82623d38b9ba A_1
+  |/
+  | x  1:007dc284c1f8 A_0
+  |/
+  @  0:d20a80d4def3 base
+  
+  $ hg debugsuccessorssets 'all()'
+  d20a80d4def3
+      d20a80d4def3
+  007dc284c1f8
+      01f36c5a8fda a139f71be9da
+  82623d38b9ba
+      01f36c5a8fda
+  392fd25390da
+      a139f71be9da
+  01f36c5a8fda
+      01f36c5a8fda
+  6a411f0d7a0a
+      a139f71be9da
+  e442cfc57690
+      a139f71be9da
+  3750ebee865d
+      a139f71be9da
+  7ae126973a96
+      a139f71be9da
+  14608b260df8
+      a139f71be9da
+  bed64f5d2f5a
+      a139f71be9da
+  a139f71be9da
+      a139f71be9da
+  $ hg log -r 'divergent()'
+
+  $ cd ..
+
+
+Subset does not diverge
+------------------------------
+
+Do not report divergent successors-set if it is a subset of another
+successors-set. (report [A,B] not [A] + [A,B])
+
+  $ newcase subset
+  $ hg debugobsolete `getid A_0` `getid A_2`
+  $ hg debugobsolete `getid A_0` `getid A_1` `getid A_2`
+  $ hg debugsuccessorssets 'desc('A_0')'
+  007dc284c1f8
+      82623d38b9ba 392fd25390da
+
+  $ cd ..

--- a/tests/test-obsolete.t	Tue Oct 23 15:44:24 2012 +0200
+++ b/tests/test-obsolete.t	Tue Oct 23 16:36:29 2012 +0200
@@ -644,7 +644,13 @@
   latecomer: 1 changesets
   $ hg debugobsolete `getid a7a6f2b5d8a5` `getid 50f11e5e3a63`
   $ hg log -r 'conflicting()'
-  changeset:   1[46]:50f11e5e3a63 (re)
+  changeset:   12:6db5e282cb91
+  parent:      10:2033b4e49474
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     add obsol_d'''
+  
+  changeset:   14:50f11e5e3a63
   tag:         tip
   parent:      11:9468a5f5d8b2
   user:        test

--- a/tests/test-stabilize-result.t	Tue Oct 23 15:44:24 2012 +0200
+++ b/tests/test-stabilize-result.t	Tue Oct 23 16:36:29 2012 +0200
@@ -297,7 +297,10 @@
   Working directory parent is obsolete
   $ echo 'gotta break' >> a
   $ hg amend
-  1 new divergent changesets
+  2 new divergent changesets
+  $ hg phase 'divergent()'
+  22: draft
+  24: draft
   $ hg evolve -qn
   hg update -c c956a4b140b6 &&
   hg merge ac6d600735a4 &&