Index: hgext/rebase.py
===================================================================
--- hgext/rebase.py
+++ hgext/rebase.py
@@ -480,11 +480,22 @@
                     merging = p2 != nullrev
                     editform = cmdutil.mergeeditform(merging, 'rebase')
                     editor = cmdutil.getcommiteditor(editform=editform, **opts)
-                    newnode = concludenode(repo, rev, p1, p2,
-                                           extrafn=_makeextrafn(self.extrafns),
-                                           editor=editor,
-                                           keepbranches=self.keepbranchesf,
-                                           date=self.date)
+                    if self.wctx.isinmemory():
+                        newnode = concludememorynode(repo, rev, p1, p2,
+                                               wctx=self.wctx,
+                                               extrafn=_makeextrafn(self.extrafns),
+                                               editor=editor,
+                                               keepbranches=self.keepbranchesf,
+                                               date=self.date)
+                        mergemod.mergestate.clean(repo)
+                    else:
+                        newnode = concludenode(repo, rev, p1, p2,
+                                               extrafn=_makeextrafn(
+                                                   self.extrafns),
+                                               editor=editor,
+                                               keepbranches=self.keepbranchesf,
+                                               date=self.date)
+
                     if newnode is None:
                         # If it ended up being a no-op commit, then the normal
                         # merge state clean-up path doesn't happen, so do it
@@ -537,13 +548,21 @@
             dsguard = None
             if ui.configbool('rebase', 'singletransaction'):
                 dsguard = dirstateguard.dirstateguard(repo, 'rebase')
-            with util.acceptintervention(dsguard):
-                newnode = concludenode(repo, revtoreuse, p1, self.external,
-                                       commitmsg=commitmsg,
-                                       extrafn=_makeextrafn(self.extrafns),
-                                       editor=editor,
-                                       keepbranches=self.keepbranchesf,
-                                       date=self.date)
+            if self.inmemory:
+                newnode = concludememorynode(repo, revtoreuse, p1, self.external,
+                                             commitmsg=commitmsg,
+                                             extrafn=_makeextrafn(self.extrafns),
+                                             editor=editor,
+                                             keepbranches=self.keepbranchesf,
+                                             date=self.date, wctx=self.wctx)
+            else:
+                with util.acceptintervention(dsguard):
+                    newnode = concludenode(repo, revtoreuse, p1, self.external,
+                                           commitmsg=commitmsg,
+                                           extrafn=_makeextrafn(self.extrafns),
+                                           editor=editor,
+                                           keepbranches=self.keepbranchesf,
+                                           date=self.date)
             if newnode is not None:
                 newrev = repo[newnode].rev()
                 for oldrev in self.state.iterkeys():
@@ -939,6 +958,34 @@
                      (max(destancestors),
                       ', '.join(str(p) for p in sorted(parents))))
 
+def concludememorynode(repo, rev, p1, p2, wctx=None,
+                       commitmsg=None, editor=None, extrafn=None,
+                       keepbranches=False, date=None):
+    '''Commit the wd changes with parents p1 and p2. Reuse commit info from rev
+    but also store useful information in extra.
+    Return node of committed revision.'''
+    ctx = repo[rev]
+    if commitmsg is None:
+        commitmsg = ctx.description()
+    keepbranch = keepbranches and repo[p1].branch() != ctx.branch()
+    extra = {'rebase_source': ctx.hex()}
+    if extrafn:
+        extrafn(ctx, extra)
+
+    destphase = max(ctx.phase(), phases.draft)
+    overrides = {('phases', 'new-commit'): destphase}
+    with repo.ui.configoverride(overrides, 'rebase'):
+        if keepbranch:
+            repo.ui.setconfig('ui', 'allowemptycommit', True)
+        if date is None:
+            date = ctx.date()
+
+        res = wctx.commit(text=commitmsg, user=ctx.user(),
+                          date=date, extra=extra, branch=repo[p1].branch(),
+                          editor=editor, parents=(p1, p2))
+        wctx.clean()
+        return res
+
 def concludenode(repo, rev, p1, p2, commitmsg=None, editor=None, extrafn=None,
                  keepbranches=False, date=None):
     '''Commit the wd changes with parents p1 and p2. Reuse commit info from rev