--- a/hgext/evolve.py	Thu Aug 23 12:51:34 2012 +0200
+++ b/hgext/evolve.py	Thu Aug 23 12:51:06 2012 +0200
@@ -843,6 +843,57 @@
     finally:
         wlock.release()
 
+@command('^fold',
+    [('r', 'rev', [], 'revision to fold'),],
+    # allow to choose the seed ?
+    _('[-r] revs'))
+def fold(ui, repo, *revs, **opts):
+    """Fold multiple revision into a single one"""
+    revs = list(revs)
+    revs.extend(opts['rev'])
+    if not revs:
+        revs = ['.']
+    revs = scmutil.revrange(repo, revs)
+    if not revs:
+        ui.write_err('no revision to fold\n')
+        return 1
+    roots = repo.revs('roots(%ld)', revs)
+    if len(roots) > 1:
+        raise util.Abort("set have multiple roots")
+    root = repo[roots[0]]
+    if root.phase() <= phases.public:
+        raise util.Abort("can't touch public revision")
+    heads = repo.revs('heads(%ld)', revs)
+    if len(heads) > 1:
+        raise util.Abort("set have multiple heads")
+    head = repo[heads[0]]
+    obsolete = extensions.find('obsolete')
+    wlock = repo.wlock()
+    try:
+        lock = repo.lock()
+        try:
+            tr = repo.transaction('touch')
+            try:
+                allctx = [repo[r] for r in revs]
+                targetphase = max(c.phase() for c in allctx)
+                msg = '\n\n***\n\n'.join(c.description() for c in allctx)
+                newid, _ = rewrite(repo, root, allctx, head,
+                                 [root.p1().node(), root.p2().node()],
+                                 commitopts={'message': msg})
+                phases.retractboundary(repo, targetphase, [newid])
+                obsolete.createmarkers(repo, [(ctx, (repo[newid],))
+                                               for ctx in allctx])
+                tr.close()
+            finally:
+                tr.release()
+        finally:
+            lock.release()
+        ui.status('%i changesets folded\n' % len(revs))
+        if repo.revs('. and %ld', revs):
+            repo.dirstate.setparents(newid, node.nullid)
+    finally:
+        wlock.release()
+
 
 def graftwrapper(orig, ui, repo, *revs, **kwargs):
     kwargs = dict(kwargs)