rebase: rewrite core algorithm (issue5578) (issue5630)

"defineparents" is the core algorithm of rebase. The old code has too many
tech debts (like outdated comments, confusing assertions, etc) and is very
error-prone to be improved. This patch rewrites "defineparents" to make the
code easier to reason about, and solve a bunch of issues, including:

  - Assertion error: no base found (demonstrated by D212, issue5578)
  - Asymmetric result (demonstrated by D211, "F with one parent")
  - Wrong new parent (demonstrated by D262, "C':A'A'")
  - "revlog index out of range" (demonstrated by D262, issue5630)
  - "nothing to merge" (demonstrated by D262)

As a side effect, merge base decision has been made more solid - rebase now
prints out explicitly what could go wrong when it cannot find a unique
suitable merge base.

.. fix:: Issue 5578, Issue 5630

   Core rebase algorithm has been rewritten to be more robust.

Differential Revision: https://phab.mercurial-scm.org/D21

hgext/rebase.py

@@ -1,1550 +1,1601 b''
 # rebase.py - rebasing feature for mercurial
 #
 # Copyright 2008 Stefano Tortarolo <stefano.tortarolo at gmail dot com>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 '''command to move sets of revisions to a different ancestor
 
 This extension lets you rebase changesets in an existing Mercurial
 repository.
 
 For more information:
 https://mercurial-scm.org/wiki/RebaseExtension
 '''
 
 from __future__ import absolute_import
 
 import errno
 import os
 
 from mercurial.i18n import _
 from mercurial.node import (
     hex,
     nullid,
     nullrev,
     short,
 )
 from mercurial import (
     bookmarks,
     cmdutil,
     commands,
     copies,
     destutil,
     dirstateguard,
     error,
     extensions,
     hg,
     lock,
     merge as mergemod,
     mergeutil,
     obsolete,
     obsutil,
     patch,
     phases,
     registrar,
     repair,
     repoview,
     revset,
     scmutil,
     smartset,
     util,
 )
 
 release = lock.release
 templateopts = cmdutil.templateopts
 
 # The following constants are used throughout the rebase module. The ordering of
 # their values must be maintained.
 
 # Indicates that a revision needs to be rebased
 revtodo = -1
 nullmerge = -2
 revignored = -3
 # successor in rebase destination
 revprecursor = -4
 # plain prune (no successor)
 revpruned = -5
-revskipped = (revignored, revprecursor, revpruned)
 
 cmdtable = {}
 command = registrar.command(cmdtable)
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'ships-with-hg-core'
 
 def _nothingtorebase():
     return 1
 
 def _savegraft(ctx, extra):
     s = ctx.extra().get('source', None)
     if s is not None:
         extra['source'] = s
     s = ctx.extra().get('intermediate-source', None)
     if s is not None:
         extra['intermediate-source'] = s
 
 def _savebranch(ctx, extra):
     extra['branch'] = ctx.branch()
 
 def _makeextrafn(copiers):
     """make an extrafn out of the given copy-functions.
 
     A copy function takes a context and an extra dict, and mutates the
     extra dict as needed based on the given context.
     """
     def extrafn(ctx, extra):
         for c in copiers:
             c(ctx, extra)
     return extrafn
 
 def _destrebase(repo, sourceset, destspace=None):
     """small wrapper around destmerge to pass the right extra args
 
     Please wrap destutil.destmerge instead."""
     return destutil.destmerge(repo, action='rebase', sourceset=sourceset,
                               onheadcheck=False, destspace=destspace)
 
 revsetpredicate = registrar.revsetpredicate()
 
 @revsetpredicate('_destrebase')
 def _revsetdestrebase(repo, subset, x):
     # ``_rebasedefaultdest()``
 
     # default destination for rebase.
     # # XXX: Currently private because I expect the signature to change.
     # # XXX: - bailing out in case of ambiguity vs returning all data.
     # i18n: "_rebasedefaultdest" is a keyword
     sourceset = None
     if x is not None:
         sourceset = revset.getset(repo, smartset.fullreposet(repo), x)
     return subset & smartset.baseset([_destrebase(repo, sourceset)])
 
 class rebaseruntime(object):
     """This class is a container for rebase runtime state"""
     def __init__(self, repo, ui, opts=None):
         if opts is None:
             opts = {}
 
         self.repo = repo
         self.ui = ui
         self.opts = opts
         self.originalwd = None
         self.external = nullrev
         # Mapping between the old revision id and either what is the new rebased
         # revision or what needs to be done with the old revision. The state
         # dict will be what contains most of the rebase progress state.
         self.state = {}
         self.activebookmark = None
         self.dest = None
         self.skipped = set()
         self.destancestors = set()
 
         self.collapsef = opts.get('collapse', False)
         self.collapsemsg = cmdutil.logmessage(ui, opts)
         self.date = opts.get('date', None)
 
         e = opts.get('extrafn') # internal, used by e.g. hgsubversion
         self.extrafns = [_savegraft]
         if e:
             self.extrafns = [e]
 
         self.keepf = opts.get('keep', False)
         self.keepbranchesf = opts.get('keepbranches', False)
         # keepopen is not meant for use on the command line, but by
         # other extensions
         self.keepopen = opts.get('keepopen', False)
         self.obsoletenotrebased = {}
 
     def storestatus(self, tr=None):
         """Store the current status to allow recovery"""
         if tr:
             tr.addfilegenerator('rebasestate', ('rebasestate',),
                                 self._writestatus, location='plain')
         else:
             with self.repo.vfs("rebasestate", "w") as f:
                 self._writestatus(f)
 
     def _writestatus(self, f):
         repo = self.repo.unfiltered()
         f.write(repo[self.originalwd].hex() + '\n')
         f.write(repo[self.dest].hex() + '\n')
         f.write(repo[self.external].hex() + '\n')
         f.write('%d\n' % int(self.collapsef))
         f.write('%d\n' % int(self.keepf))
         f.write('%d\n' % int(self.keepbranchesf))
         f.write('%s\n' % (self.activebookmark or ''))
         for d, v in self.state.iteritems():
             oldrev = repo[d].hex()
             if v >= 0:
                 newrev = repo[v].hex()
             elif v == revtodo:
                 # To maintain format compatibility, we have to use nullid.
                 # Please do remove this special case when upgrading the format.
                 newrev = hex(nullid)
             else:
                 newrev = v
             f.write("%s:%s\n" % (oldrev, newrev))
         repo.ui.debug('rebase status stored\n')
 
     def restorestatus(self):
         """Restore a previously stored status"""
         repo = self.repo
         keepbranches = None
         dest = None
         collapse = False
         external = nullrev
         activebookmark = None
         state = {}
 
         try:
             f = repo.vfs("rebasestate")
             for i, l in enumerate(f.read().splitlines()):
                 if i == 0:
                     originalwd = repo[l].rev()
                 elif i == 1:
                     dest = repo[l].rev()
                 elif i == 2:
                     external = repo[l].rev()
                 elif i == 3:
                     collapse = bool(int(l))
                 elif i == 4:
                     keep = bool(int(l))
                 elif i == 5:
                     keepbranches = bool(int(l))
                 elif i == 6 and not (len(l) == 81 and ':' in l):
                     # line 6 is a recent addition, so for backwards
                     # compatibility check that the line doesn't look like the
                     # oldrev:newrev lines
                     activebookmark = l
                 else:
                     oldrev, newrev = l.split(':')
                     if newrev in (str(nullmerge), str(revignored),
                                   str(revprecursor), str(revpruned)):
                         state[repo[oldrev].rev()] = int(newrev)
                     elif newrev == nullid:
                         state[repo[oldrev].rev()] = revtodo
                         # Legacy compat special case
                     else:
                         state[repo[oldrev].rev()] = repo[newrev].rev()
 
         except IOError as err:
             if err.errno != errno.ENOENT:
                 raise
             cmdutil.wrongtooltocontinue(repo, _('rebase'))
 
         if keepbranches is None:
             raise error.Abort(_('.hg/rebasestate is incomplete'))
 
         skipped = set()
         # recompute the set of skipped revs
         if not collapse:
             seen = {dest}
             for old, new in sorted(state.items()):
                 if new != revtodo and new in seen:
                     skipped.add(old)
                 seen.add(new)
         repo.ui.debug('computed skipped revs: %s\n' %
                         (' '.join(str(r) for r in sorted(skipped)) or None))
         repo.ui.debug('rebase status resumed\n')
         _setrebasesetvisibility(repo, set(state.keys()) | {originalwd})
 
         self.originalwd = originalwd
         self.dest = dest
         self.state = state
         self.skipped = skipped
         self.collapsef = collapse
         self.keepf = keep
         self.keepbranchesf = keepbranches
         self.external = external
         self.activebookmark = activebookmark
 
     def _handleskippingobsolete(self, rebaserevs, obsoleterevs, dest):
         """Compute structures necessary for skipping obsolete revisions
 
         rebaserevs:     iterable of all revisions that are to be rebased
         obsoleterevs:   iterable of all obsolete revisions in rebaseset
         dest:           a destination revision for the rebase operation
         """
         self.obsoletenotrebased = {}
         if not self.ui.configbool('experimental', 'rebaseskipobsolete',
                                   default=True):
             return
         rebaseset = set(rebaserevs)
         obsoleteset = set(obsoleterevs)
         self.obsoletenotrebased = _computeobsoletenotrebased(self.repo,
                                     obsoleteset, dest)
         skippedset = set(self.obsoletenotrebased)
         _checkobsrebase(self.repo, self.ui, obsoleteset, rebaseset, skippedset)
 
     def _prepareabortorcontinue(self, isabort):
         try:
             self.restorestatus()
             self.collapsemsg = restorecollapsemsg(self.repo, isabort)
         except error.RepoLookupError:
             if isabort:
                 clearstatus(self.repo)
                 clearcollapsemsg(self.repo)
                 self.repo.ui.warn(_('rebase aborted (no revision is removed,'
                                     ' only broken state is cleared)\n'))
                 return 0
             else:
                 msg = _('cannot continue inconsistent rebase')
                 hint = _('use "hg rebase --abort" to clear broken state')
                 raise error.Abort(msg, hint=hint)
         if isabort:
             return abort(self.repo, self.originalwd, self.dest,
                          self.state, activebookmark=self.activebookmark)
 
         obsrevs = (r for r, st in self.state.items() if st == revprecursor)
         self._handleskippingobsolete(self.state.keys(), obsrevs, self.dest)
 
     def _preparenewrebase(self, dest, rebaseset):
         if dest is None:
             return _nothingtorebase()
 
         allowunstable = obsolete.isenabled(self.repo, obsolete.allowunstableopt)
         if (not (self.keepf or allowunstable)
               and self.repo.revs('first(children(%ld) - %ld)',
                                  rebaseset, rebaseset)):
             raise error.Abort(
                 _("can't remove original changesets with"
                   " unrebased descendants"),
                 hint=_('use --keep to keep original changesets'))
 
         obsrevs = _filterobsoleterevs(self.repo, set(rebaseset))
         self._handleskippingobsolete(rebaseset, obsrevs, dest.rev())
 
         result = buildstate(self.repo, dest, rebaseset, self.collapsef,
                             self.obsoletenotrebased)
 
         if not result:
             # Empty state built, nothing to rebase
             self.ui.status(_('nothing to rebase\n'))
             return _nothingtorebase()
 
         for root in self.repo.set('roots(%ld)', rebaseset):
             if not self.keepf and not root.mutable():
                 raise error.Abort(_("can't rebase public changeset %s")
                                   % root,
                                   hint=_("see 'hg help phases' for details"))
 
         (self.originalwd, self.dest, self.state) = result
         if self.collapsef:
             self.destancestors = self.repo.changelog.ancestors(
                                         [self.dest],
                                         inclusive=True)
             self.external = externalparent(self.repo, self.state,
                                               self.destancestors)
 
         if dest.closesbranch() and not self.keepbranchesf:
             self.ui.status(_('reopening closed branch head %s\n') % dest)
 
     def _performrebase(self, tr):
         repo, ui, opts = self.repo, self.ui, self.opts
         if self.keepbranchesf:
             # insert _savebranch at the start of extrafns so if
             # there's a user-provided extrafn it can clobber branch if
             # desired
             self.extrafns.insert(0, _savebranch)
             if self.collapsef:
                 branches = set()
                 for rev in self.state:
                     branches.add(repo[rev].branch())
                     if len(branches) > 1:
                         raise error.Abort(_('cannot collapse multiple named '
                             'branches'))
 
         # Rebase
         if not self.destancestors:
             self.destancestors = repo.changelog.ancestors([self.dest],
                                                           inclusive=True)
 
         # Keep track of the active bookmarks in order to reset them later
         self.activebookmark = self.activebookmark or repo._activebookmark
         if self.activebookmark:
             bookmarks.deactivate(repo)
 
         # Store the state before we begin so users can run 'hg rebase --abort'
         # if we fail before the transaction closes.
         self.storestatus()
 
         sortedrevs = repo.revs('sort(%ld, -topo)', self.state)
         cands = [k for k, v in self.state.iteritems() if v == revtodo]
         total = len(cands)
         pos = 0
         for rev in sortedrevs:
             ctx = repo[rev]
             desc = '%d:%s "%s"' % (ctx.rev(), ctx,
                                    ctx.description().split('\n', 1)[0])
             names = repo.nodetags(ctx.node()) + repo.nodebookmarks(ctx.node())
             if names:
                 desc += ' (%s)' % ' '.join(names)
             if self.state[rev] == rev:
                 ui.status(_('already rebased %s\n') % desc)
             elif self.state[rev] == revtodo:
                 pos += 1
                 ui.status(_('rebasing %s\n') % desc)
                 ui.progress(_("rebasing"), pos, ("%d:%s" % (rev, ctx)),
                             _('changesets'), total)
-                p1, p2, base = defineparents(repo, rev, self.dest,
-                                             self.state,
-                                             self.destancestors,
-                                             self.obsoletenotrebased)
+                p1, p2, base = defineparents(repo, rev, self.dest, self.state)
                 self.storestatus(tr=tr)
                 storecollapsemsg(repo, self.collapsemsg)
                 if len(repo[None].parents()) == 2:
                     repo.ui.debug('resuming interrupted rebase\n')
                 else:
                     try:
                         ui.setconfig('ui', 'forcemerge', opts.get('tool', ''),
                                      'rebase')
                         stats = rebasenode(repo, rev, p1, base, self.state,
                                            self.collapsef, self.dest)
                         if stats and stats[3] > 0:
                             raise error.InterventionRequired(
                                 _('unresolved conflicts (see hg '
                                   'resolve, then hg rebase --continue)'))
                     finally:
                         ui.setconfig('ui', 'forcemerge', '', 'rebase')
                 if not self.collapsef:
                     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 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
                         # here. Fix issue5494
                         mergemod.mergestate.clean(repo)
                 else:
                     # Skip commit if we are collapsing
                     repo.setparents(repo[p1].node())
                     newnode = None
                 # Update the state
                 if newnode is not None:
                     self.state[rev] = repo[newnode].rev()
                     ui.debug('rebased as %s\n' % short(newnode))
                 else:
                     if not self.collapsef:
                         ui.warn(_('note: rebase of %d:%s created no changes '
                                   'to commit\n') % (rev, ctx))
                         self.skipped.add(rev)
                     self.state[rev] = p1
                     ui.debug('next revision set to %s\n' % p1)
             elif self.state[rev] == nullmerge:
                 ui.debug('ignoring null merge rebase of %s\n' % rev)
             elif self.state[rev] == revignored:
                 ui.status(_('not rebasing ignored %s\n') % desc)
             elif self.state[rev] == revprecursor:
                 destctx = repo[self.obsoletenotrebased[rev]]
                 descdest = '%d:%s "%s"' % (destctx.rev(), destctx,
                            destctx.description().split('\n', 1)[0])
                 msg = _('note: not rebasing %s, already in destination as %s\n')
                 ui.status(msg % (desc, descdest))
             elif self.state[rev] == revpruned:
                 msg = _('note: not rebasing %s, it has no successor\n')
                 ui.status(msg % desc)
             else:
                 ui.status(_('already rebased %s as %s\n') %
                           (desc, repo[self.state[rev]]))
 
         ui.progress(_('rebasing'), None)
         ui.note(_('rebase merging completed\n'))
 
     def _finishrebase(self):
         repo, ui, opts = self.repo, self.ui, self.opts
         if self.collapsef and not self.keepopen:
             p1, p2, _base = defineparents(repo, min(self.state),
-                                          self.dest, self.state,
-                                          self.destancestors,
-                                          self.obsoletenotrebased)
+                                          self.dest, self.state)
             editopt = opts.get('edit')
             editform = 'rebase.collapse'
             if self.collapsemsg:
                 commitmsg = self.collapsemsg
             else:
                 commitmsg = 'Collapsed revision'
                 for rebased in sorted(self.state):
                     if rebased not in self.skipped and\
                        self.state[rebased] > nullmerge:
                         commitmsg += '\n* %s' % repo[rebased].description()
                 editopt = True
             editor = cmdutil.getcommiteditor(edit=editopt, editform=editform)
             revtoreuse = max(self.state)
 
             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 newnode is None:
                 newrev = self.dest
             else:
                 newrev = repo[newnode].rev()
             for oldrev in self.state.iterkeys():
                 if self.state[oldrev] > nullmerge:
                     self.state[oldrev] = newrev
 
         if 'qtip' in repo.tags():
             updatemq(repo, self.state, self.skipped, **opts)
 
         # restore original working directory
         # (we do this before stripping)
         newwd = self.state.get(self.originalwd, self.originalwd)
         if newwd == revprecursor:
             newwd = self.obsoletenotrebased[self.originalwd]
         elif newwd < 0:
             # original directory is a parent of rebase set root or ignored
             newwd = self.originalwd
         if newwd not in [c.rev() for c in repo[None].parents()]:
             ui.note(_("update back to initial working directory parent\n"))
             hg.updaterepo(repo, newwd, False)
 
         if not self.keepf:
             collapsedas = None
             if self.collapsef:
                 collapsedas = newnode
             clearrebased(ui, repo, self.dest, self.state, self.skipped,
                          collapsedas)
 
         clearstatus(repo)
         clearcollapsemsg(repo)
 
         ui.note(_("rebase completed\n"))
         util.unlinkpath(repo.sjoin('undo'), ignoremissing=True)
         if self.skipped:
             skippedlen = len(self.skipped)
             ui.note(_("%d revisions have been skipped\n") % skippedlen)
 
         if (self.activebookmark and self.activebookmark in repo._bookmarks and
             repo['.'].node() == repo._bookmarks[self.activebookmark]):
                 bookmarks.activate(repo, self.activebookmark)
 
 @command('rebase',
     [('s', 'source', '',
      _('rebase the specified changeset and descendants'), _('REV')),
     ('b', 'base', '',
      _('rebase everything from branching point of specified changeset'),
      _('REV')),
     ('r', 'rev', [],
      _('rebase these revisions'),
      _('REV')),
     ('d', 'dest', '',
      _('rebase onto the specified changeset'), _('REV')),
     ('', 'collapse', False, _('collapse the rebased changesets')),
     ('m', 'message', '',
      _('use text as collapse commit message'), _('TEXT')),
     ('e', 'edit', False, _('invoke editor on commit messages')),
     ('l', 'logfile', '',
      _('read collapse commit message from file'), _('FILE')),
     ('k', 'keep', False, _('keep original changesets')),
     ('', 'keepbranches', False, _('keep original branch names')),
     ('D', 'detach', False, _('(DEPRECATED)')),
     ('i', 'interactive', False, _('(DEPRECATED)')),
     ('t', 'tool', '', _('specify merge tool')),
     ('c', 'continue', False, _('continue an interrupted rebase')),
     ('a', 'abort', False, _('abort an interrupted rebase'))] +
      templateopts,
     _('[-s REV | -b REV] [-d REV] [OPTION]'))
 def rebase(ui, repo, **opts):
     """move changeset (and descendants) to a different branch
 
     Rebase uses repeated merging to graft changesets from one part of
     history (the source) onto another (the destination). This can be
     useful for linearizing *local* changes relative to a master
     development tree.
 
     Published commits cannot be rebased (see :hg:`help phases`).
     To copy commits, see :hg:`help graft`.
 
     If you don't specify a destination changeset (``-d/--dest``), rebase
     will use the same logic as :hg:`merge` to pick a destination.  if
     the current branch contains exactly one other head, the other head
     is merged with by default.  Otherwise, an explicit revision with
     which to merge with must be provided.  (destination changeset is not
     modified by rebasing, but new changesets are added as its
     descendants.)
 
     Here are the ways to select changesets:
 
       1. Explicitly select them using ``--rev``.
 
       2. Use ``--source`` to select a root changeset and include all of its
          descendants.
 
       3. Use ``--base`` to select a changeset; rebase will find ancestors
          and their descendants which are not also ancestors of the destination.
 
       4. If you do not specify any of ``--rev``, ``source``, or ``--base``,
          rebase will use ``--base .`` as above.
 
     Rebase will destroy original changesets unless you use ``--keep``.
     It will also move your bookmarks (even if you do).
 
     Some changesets may be dropped if they do not contribute changes
     (e.g. merges from the destination branch).
 
     Unlike ``merge``, rebase will do nothing if you are at the branch tip of
     a named branch with two heads. You will need to explicitly specify source
     and/or destination.
 
     If you need to use a tool to automate merge/conflict decisions, you
     can specify one with ``--tool``, see :hg:`help merge-tools`.
     As a caveat: the tool will not be used to mediate when a file was
     deleted, there is no hook presently available for this.
 
     If a rebase is interrupted to manually resolve a conflict, it can be
     continued with --continue/-c or aborted with --abort/-a.
 
     .. container:: verbose
 
       Examples:
 
       - move "local changes" (current commit back to branching point)
         to the current branch tip after a pull::
 
           hg rebase
 
       - move a single changeset to the stable branch::
 
           hg rebase -r 5f493448 -d stable
 
       - splice a commit and all its descendants onto another part of history::
 
           hg rebase --source c0c3 --dest 4cf9
 
       - rebase everything on a branch marked by a bookmark onto the
         default branch::
 
           hg rebase --base myfeature --dest default
 
       - collapse a sequence of changes into a single commit::
 
           hg rebase --collapse -r 1520:1525 -d .
 
       - move a named branch while preserving its name::
 
           hg rebase -r "branch(featureX)" -d 1.3 --keepbranches
 
     Configuration Options:
 
     You can make rebase require a destination if you set the following config
     option::
 
       [commands]
       rebase.requiredest = True
 
     By default, rebase will close the transaction after each commit. For
     performance purposes, you can configure rebase to use a single transaction
     across the entire rebase. WARNING: This setting introduces a significant
     risk of losing the work you've done in a rebase if the rebase aborts
     unexpectedly::
 
       [rebase]
       singletransaction = True
 
     Return Values:
 
     Returns 0 on success, 1 if nothing to rebase or there are
     unresolved conflicts.
 
     """
     rbsrt = rebaseruntime(repo, ui, opts)
 
     with repo.wlock(), repo.lock():
         # Validate input and define rebasing points
         destf = opts.get('dest', None)
         srcf = opts.get('source', None)
         basef = opts.get('base', None)
         revf = opts.get('rev', [])
         # search default destination in this space
         # used in the 'hg pull --rebase' case, see issue 5214.
         destspace = opts.get('_destspace')
         contf = opts.get('continue')
         abortf = opts.get('abort')
         if opts.get('interactive'):
             try:
                 if extensions.find('histedit'):
                     enablehistedit = ''
             except KeyError:
                 enablehistedit = " --config extensions.histedit="
             help = "hg%s help -e histedit" % enablehistedit
             msg = _("interactive history editing is supported by the "
                     "'histedit' extension (see \"%s\")") % help
             raise error.Abort(msg)
 
         if rbsrt.collapsemsg and not rbsrt.collapsef:
             raise error.Abort(
                 _('message can only be specified with collapse'))
 
         if contf or abortf:
             if contf and abortf:
                 raise error.Abort(_('cannot use both abort and continue'))
             if rbsrt.collapsef:
                 raise error.Abort(
                     _('cannot use collapse with continue or abort'))
             if srcf or basef or destf:
                 raise error.Abort(
                     _('abort and continue do not allow specifying revisions'))
             if abortf and opts.get('tool', False):
                 ui.warn(_('tool option will be ignored\n'))
             if contf:
                 ms = mergemod.mergestate.read(repo)
                 mergeutil.checkunresolved(ms)
 
             retcode = rbsrt._prepareabortorcontinue(abortf)
             if retcode is not None:
                 return retcode
         else:
             dest, rebaseset = _definesets(ui, repo, destf, srcf, basef, revf,
                                           destspace=destspace)
             retcode = rbsrt._preparenewrebase(dest, rebaseset)
             if retcode is not None:
                 return retcode
 
         tr = None
         dsguard = None
 
         singletr = ui.configbool('rebase', 'singletransaction')
         if singletr:
             tr = repo.transaction('rebase')
         with util.acceptintervention(tr):
             if singletr:
                 dsguard = dirstateguard.dirstateguard(repo, 'rebase')
             with util.acceptintervention(dsguard):
                 rbsrt._performrebase(tr)
 
         rbsrt._finishrebase()
 
 def _definesets(ui, repo, destf=None, srcf=None, basef=None, revf=None,
                 destspace=None):
     """use revisions argument to define destination and rebase set
     """
     if revf is None:
         revf = []
 
     # destspace is here to work around issues with `hg pull --rebase` see
     # issue5214 for details
     if srcf and basef:
         raise error.Abort(_('cannot specify both a source and a base'))
     if revf and basef:
         raise error.Abort(_('cannot specify both a revision and a base'))
     if revf and srcf:
         raise error.Abort(_('cannot specify both a revision and a source'))
 
     cmdutil.checkunfinished(repo)
     cmdutil.bailifchanged(repo)
 
     if ui.configbool('commands', 'rebase.requiredest') and not destf:
         raise error.Abort(_('you must specify a destination'),
                           hint=_('use: hg rebase -d REV'))
 
     if destf:
         dest = scmutil.revsingle(repo, destf)
 
     if revf:
         rebaseset = scmutil.revrange(repo, revf)
         if not rebaseset:
             ui.status(_('empty "rev" revision set - nothing to rebase\n'))
             return None, None
     elif srcf:
         src = scmutil.revrange(repo, [srcf])
         if not src:
             ui.status(_('empty "source" revision set - nothing to rebase\n'))
             return None, None
         rebaseset = repo.revs('(%ld)::', src)
         assert rebaseset
     else:
         base = scmutil.revrange(repo, [basef or '.'])
         if not base:
             ui.status(_('empty "base" revision set - '
                         "can't compute rebase set\n"))
             return None, None
         if not destf:
             dest = repo[_destrebase(repo, base, destspace=destspace)]
             destf = str(dest)
 
         roots = [] # selected children of branching points
         bpbase = {} # {branchingpoint: [origbase]}
         for b in base: # group bases by branching points
             bp = repo.revs('ancestor(%d, %d)', b, dest).first()
             bpbase[bp] = bpbase.get(bp, []) + [b]
         if None in bpbase:
             # emulate the old behavior, showing "nothing to rebase" (a better
             # behavior may be abort with "cannot find branching point" error)
             bpbase.clear()
         for bp, bs in bpbase.iteritems(): # calculate roots
             roots += list(repo.revs('children(%d) & ancestors(%ld)', bp, bs))
 
         rebaseset = repo.revs('%ld::', roots)
 
         if not rebaseset:
             # transform to list because smartsets are not comparable to
             # lists. This should be improved to honor laziness of
             # smartset.
             if list(base) == [dest.rev()]:
                 if basef:
                     ui.status(_('nothing to rebase - %s is both "base"'
                                 ' and destination\n') % dest)
                 else:
                     ui.status(_('nothing to rebase - working directory '
                                 'parent is also destination\n'))
             elif not repo.revs('%ld - ::%d', base, dest):
                 if basef:
                     ui.status(_('nothing to rebase - "base" %s is '
                                 'already an ancestor of destination '
                                 '%s\n') %
                               ('+'.join(str(repo[r]) for r in base),
                                dest))
                 else:
                     ui.status(_('nothing to rebase - working '
                                 'directory parent is already an '
                                 'ancestor of destination %s\n') % dest)
             else: # can it happen?
                 ui.status(_('nothing to rebase from %s to %s\n') %
                           ('+'.join(str(repo[r]) for r in base), dest))
             return None, None
 
     if not destf:
         dest = repo[_destrebase(repo, rebaseset, destspace=destspace)]
         destf = str(dest)
 
     return dest, rebaseset
 
 def externalparent(repo, state, destancestors):
     """Return the revision that should be used as the second parent
     when the revisions in state is collapsed on top of destancestors.
     Abort if there is more than one parent.
     """
     parents = set()
     source = min(state)
     for rev in state:
         if rev == source:
             continue
         for p in repo[rev].parents():
             if (p.rev() not in state
                         and p.rev() not in destancestors):
                 parents.add(p.rev())
     if not parents:
         return nullrev
     if len(parents) == 1:
         return parents.pop()
     raise error.Abort(_('unable to collapse on top of %s, there is more '
                        'than one external parent: %s') %
                      (max(destancestors),
                       ', '.join(str(p) for p in sorted(parents))))
 
 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
     but also store useful information in extra.
     Return node of committed revision.'''
     dsguard = util.nullcontextmanager()
     if not repo.ui.configbool('rebase', 'singletransaction'):
         dsguard = dirstateguard.dirstateguard(repo, 'rebase')
     with dsguard:
         repo.setparents(repo[p1].node(), repo[p2].node())
         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)
             # Commit might fail if unresolved files exist
             if date is None:
                 date = ctx.date()
             newnode = repo.commit(text=commitmsg, user=ctx.user(),
                                   date=date, extra=extra, editor=editor)
 
         repo.dirstate.setbranch(repo[newnode].branch())
         return newnode
 
 def rebasenode(repo, rev, p1, base, state, collapse, dest):
     'Rebase a single revision rev on top of p1 using base as merge ancestor'
     # Merge phase
     # Update to destination and merge it with local
     if repo['.'].rev() != p1:
         repo.ui.debug(" update to %d:%s\n" % (p1, repo[p1]))
         mergemod.update(repo, p1, False, True)
     else:
         repo.ui.debug(" already in destination\n")
     repo.dirstate.write(repo.currenttransaction())
     repo.ui.debug(" merge against %d:%s\n" % (rev, repo[rev]))
     if base is not None:
         repo.ui.debug("   detach base %d:%s\n" % (base, repo[base]))
     # When collapsing in-place, the parent is the common ancestor, we
     # have to allow merging with it.
     stats = mergemod.update(repo, rev, True, True, base, collapse,
                             labels=['dest', 'source'])
     if collapse:
         copies.duplicatecopies(repo, rev, dest)
     else:
         # If we're not using --collapse, we need to
         # duplicate copies between the revision we're
         # rebasing and its first parent, but *not*
         # duplicate any copies that have already been
         # performed in the destination.
         p1rev = repo[rev].p1().rev()
         copies.duplicatecopies(repo, rev, p1rev, skiprev=dest)
     return stats
 
 def adjustdest(repo, rev, dest, state):
     """adjust rebase destination given the current rebase state
 
     rev is what is being rebased. Return a list of two revs, which are the
     adjusted destinations for rev's p1 and p2, respectively. If a parent is
     nullrev, return dest without adjustment for it.
 
     For example, when doing rebase -r B+E -d F, rebase will first move B to B1,
     and E's destination will be adjusted from F to B1.
 
         B1 <- written during rebasing B
         |
         F <- original destination of B, E
         |
         | E <- rev, which is being rebased
         | |
         | D <- prev, one parent of rev being checked
         | |
         | x <- skipped, ex. no successor or successor in (::dest)
         | |
         | C
         | |
         | B <- rebased as B1
         |/
         A
 
     Another example about merge changeset, rebase -r C+G+H -d K, rebase will
     first move C to C1, G to G1, and when it's checking H, the adjusted
     destinations will be [C1, G1].
 
             H       C1 G1
            /|       | /
           F G       |/
         K | |  ->   K
         | C D       |
         | |/        |
         | B         | ...
         |/          |/
         A           A
     """
     result = []
     for prev in repo.changelog.parentrevs(rev):
         adjusted = dest
         if prev != nullrev:
             # pick already rebased revs from state
             source = [s for s, d in state.items() if d > 0]
             candidate = repo.revs('max(%ld and (::%d))', source, prev).first()
             if candidate is not None:
                 adjusted = state[candidate]
         result.append(adjusted)
     return result
 
-def nearestrebased(repo, rev, state):
-    """return the nearest ancestors of rev in the rebase result"""
-    rebased = [r for r in state if state[r] > nullmerge]
-    candidates = repo.revs('max(%ld  and (::%d))', rebased, rev)
-    if candidates:
-        return state[candidates.first()]
-    else:
-        return None
-
 def _checkobsrebase(repo, ui, rebaseobsrevs, rebasesetrevs, rebaseobsskipped):
     """
     Abort if rebase will create divergence or rebase is noop because of markers
 
     `rebaseobsrevs`: set of obsolete revision in source
     `rebasesetrevs`: set of revisions to be rebased from source
     `rebaseobsskipped`: set of revisions from source skipped because they have
     successors in destination
     """
     # Obsolete node with successors not in dest leads to divergence
     divergenceok = ui.configbool('experimental',
                                  'allowdivergence')
     divergencebasecandidates = rebaseobsrevs - rebaseobsskipped
 
     if divergencebasecandidates and not divergenceok:
         divhashes = (str(repo[r])
                      for r in divergencebasecandidates)
         msg = _("this rebase will cause "
                 "divergences from: %s")
         h = _("to force the rebase please set "
               "experimental.allowdivergence=True")
         raise error.Abort(msg % (",".join(divhashes),), hint=h)
 
-def defineparents(repo, rev, dest, state, destancestors,
-                  obsoletenotrebased):
-    'Return the new parent relationship of the revision that will be rebased'
-    parents = repo[rev].parents()
-    p1 = p2 = nullrev
-    rp1 = None
+def successorrevs(repo, rev):
+    """yield revision numbers for successors of rev"""
+    unfi = repo.unfiltered()
+    nodemap = unfi.changelog.nodemap
+    for s in obsutil.allsuccessors(unfi.obsstore, [unfi[rev].node()]):
+        if s in nodemap:
+            yield nodemap[s]
 
-    p1n = parents[0].rev()
-    if p1n in destancestors:
-        p1 = dest
-    elif p1n in state:
-        if state[p1n] == nullmerge:
-            p1 = dest
-        elif state[p1n] in revskipped:
-            p1 = nearestrebased(repo, p1n, state)
-            if p1 is None:
-                p1 = dest
-        else:
-            p1 = state[p1n]
-    else: # p1n external
-        p1 = dest
-        p2 = p1n
+def defineparents(repo, rev, dest, state):
+    """Return new parents and optionally a merge base for rev being rebased
+
+    The destination specified by "dest" cannot always be used directly because
+    previously rebase result could affect destination. For example,
 
-    if len(parents) == 2 and parents[1].rev() not in destancestors:
-        p2n = parents[1].rev()
-        # interesting second parent
-        if p2n in state:
-            if p1 == dest: # p1n in destancestors or external
-                p1 = state[p2n]
-                if p1 == revprecursor:
-                    rp1 = obsoletenotrebased[p2n]
-            elif state[p2n] in revskipped:
-                p2 = nearestrebased(repo, p2n, state)
-                if p2 is None:
-                    # no ancestors rebased yet, detach
-                    p2 = dest
-            else:
-                p2 = state[p2n]
-        else: # p2n external
-            if p2 != nullrev: # p1n external too => rev is a merged revision
-                raise error.Abort(_('cannot use revision %d as base, result '
-                        'would have 3 parents') % rev)
-            p2 = p2n
-    repo.ui.debug(" future parents are %d and %d\n" %
-                            (repo[rp1 or p1].rev(), repo[p2].rev()))
+          D E    rebase -r C+D+E -d B
+          |/     C will be rebased to C'
+        B C      D's new destination will be C' instead of B
+        |/       E's new destination will be C' instead of B
+        A
+
+    The new parents of a merge is slightly more complicated. See the comment
+    block below.
+    """
+    cl = repo.changelog
+    def isancestor(a, b):
+        # take revision numbers instead of nodes
+        if a == b:
+            return True
+        elif a > b:
+            return False
+        return cl.isancestor(cl.node(a), cl.node(b))
+
+    oldps = repo.changelog.parentrevs(rev) # old parents
+    newps = [nullrev, nullrev] # new parents
+    dests = adjustdest(repo, rev, dest, state) # adjusted destinations
+    bases = list(oldps) # merge base candidates, initially just old parents
 
-    if not any(p.rev() in state for p in parents):
-        # Case (1) root changeset of a non-detaching rebase set.
-        # Let the merge mechanism find the base itself.
-        base = None
-    elif not repo[rev].p2():
-        # Case (2) detaching the node with a single parent, use this parent
-        base = repo[rev].p1().rev()
+    if all(r == nullrev for r in oldps[1:]):
+        # For non-merge changeset, just move p to adjusted dest as requested.
+        newps[0] = dests[0]
     else:
-        # Assuming there is a p1, this is the case where there also is a p2.
-        # We are thus rebasing a merge and need to pick the right merge base.
+        # For merge changeset, if we move p to dests[i] unconditionally, both
+        # parents may change and the end result looks like "the merge loses a
+        # parent", which is a surprise. This is a limit because "--dest" only
+        # accepts one dest per src.
+        #
+        # Therefore, only move p with reasonable conditions (in this order):
+        #   1. use dest, if dest is a descendent of (p or one of p's successors)
+        #   2. use p's rebased result, if p is rebased (state[p] > 0)
+        #
+        # Comparing with adjustdest, the logic here does some additional work:
+        #   1. decide which parents will not be moved towards dest
+        #   2. if the above decision is "no", should a parent still be moved
+        #      because it was rebased?
+        #
+        # For example:
         #
-        # Imagine we have:
-        # - M: current rebase revision in this step
-        # - A: one parent of M
-        # - B: other parent of M
-        # - D: destination of this merge step (p1 var)
+        #     C    # "rebase -r C -d D" is an error since none of the parents
+        #    /|    # can be moved. "rebase -r B+C -d D" will move C's parent
+        #   A B D  # B (using rule "2."), since B will be rebased.
         #
-        # Consider the case where D is a descendant of A or B and the other is
-        # 'outside'. In this case, the right merge base is the D ancestor.
+        # The loop tries to be not rely on the fact that a Mercurial node has
+        # at most 2 parents.
+        for i, p in enumerate(oldps):
+            np = p # new parent
+            if any(isancestor(x, dests[i]) for x in successorrevs(repo, p)):
+                np = dests[i]
+            elif p in state and state[p] > 0:
+                np = state[p]
+
+            # "bases" only record "special" merge bases that cannot be
+            # calculated from changelog DAG (i.e. isancestor(p, np) is False).
+            # For example:
         #
-        # An informal proof, assuming A is 'outside' and B is the D ancestor:
+            #   B'   # rebase -s B -d D, when B was rebased to B'. dest for C
+            #   | C  # is B', but merge base for C is B, instead of
+            #   D |  # changelog.ancestor(C, B') == A. If changelog DAG and
+            #   | B  # "state" edges are merged (so there will be an edge from
+            #   |/   # B to B'), the merge base is still ancestor(C, B') in
+            #   A    # the merged graph.
         #
-        # If we pick B as the base, the merge involves:
-        # - changes from B to M (actual changeset payload)
-        # - changes from B to D (induced by rebase) as D is a rebased
-        #   version of B)
-        # Which exactly represent the rebase operation.
-        #
-        # If we pick A as the base, the merge involves:
-        # - changes from A to M (actual changeset payload)
-        # - changes from A to D (with include changes between unrelated A and B
-        #   plus changes induced by rebase)
-        # Which does not represent anything sensible and creates a lot of
-        # conflicts. A is thus not the right choice - B is.
+            # Also see https://bz.mercurial-scm.org/show_bug.cgi?id=1950#c8
+            # which uses "virtual null merge" to explain this situation.
+            if isancestor(p, np):
+                bases[i] = nullrev
+
+            # If one parent becomes an ancestor of the other, drop the ancestor
+            for j, x in enumerate(newps[:i]):
+                if x == nullrev:
+                    continue
+                if isancestor(np, x):
+                    np = nullrev
+                elif isancestor(x, np):
+                    newps[j] = np
+                    np = nullrev
+                    bases[j], bases[i] = bases[i], bases[j]
+
+            newps[i] = np
+
+        # "rebasenode" updates to new p1, and the old p1 will be used as merge
+        # base. If only p2 changes, merging using unchanged p1 as merge base is
+        # suboptimal. Therefore swap parents to make the merge sane.
+        if newps[1] != nullrev and oldps[0] == newps[0]:
+            assert len(newps) == 2 and len(oldps) == 2
+            newps.reverse()
+            bases.reverse()
+
+        # No parent change might be an error because we fail to make rev a
+        # descendent of requested dest. This can happen, for example:
         #
-        # Note: The base found in this 'proof' is only correct in the specified
-        # case. This base does not make sense if is not D a descendant of A or B
-        # or if the other is not parent 'outside' (especially not if the other
-        # parent has been rebased). The current implementation does not
-        # make it feasible to consider different cases separately. In these
-        # other cases we currently just leave it to the user to correctly
-        # resolve an impossible merge using a wrong ancestor.
-        #
-        # xx, p1 could be -4, and both parents could probably be -4...
-        for p in repo[rev].parents():
-            if state.get(p.rev()) == p1:
-                base = p.rev()
-                break
-        else: # fallback when base not found
+        #     C    # rebase -r C -d D
+        #    /|    # None of A and B will be changed to D and rebase fails.
+        #   A B D
+        if set(newps) == set(oldps) and dest not in newps:
+            # The error message is for compatibility. It's a bit misleading
+            # since rebase is not supposed to add new parents.
+            raise error.Abort(_('cannot use revision %d as base, '
+                                'result would have 3 parents') % rev)
+
+    repo.ui.debug(" future parents are %d and %d\n" % tuple(newps))
+
+    # "rebasenode" updates to new p1, use the corresponding merge base.
+    if bases[0] != nullrev:
+        base = bases[0]
+    else:
             base = None
 
-            # Raise because this function is called wrong (see issue 4106)
-            raise AssertionError('no base found to rebase on '
-                                 '(defineparents called wrong)')
-    return rp1 or p1, p2, base
+    # Check if the merge will contain unwanted changes. That may happen if
+    # there are multiple special (non-changelog ancestor) merge bases, which
+    # cannot be handled well by the 3-way merge algorithm. For example:
+    #
+    #     F
+    #    /|
+    #   D E  # "rebase -r D+E+F -d Z", when rebasing F, if "D" was chosen
+    #   | |  # as merge base, the difference between D and F will include
+    #   B C  # C, so the rebased F will contain C surprisingly. If "E" was
+    #   |/   #  chosen, the rebased F will contain B.
+    #   A Z
+    #
+    # But our merge base candidates (D and E in above case) could still be
+    # better than the default (ancestor(F, Z) == null). Therefore still
+    # pick one (so choose p1 above).
+    if sum(1 for b in bases if b != nullrev) > 1:
+        assert base is not None
+
+        # Revisions in the side (not chosen as merge base) branch that might
+        # contain "surprising" contents
+        siderevs = list(repo.revs('((%ld-%d) %% (%d+%d))',
+                                  bases, base, base, dest))
+
+        # If those revisions are covered by rebaseset, the result is good.
+        # A merge in rebaseset would be considered to cover its ancestors.
+        if siderevs:
+            rebaseset = [r for r, d in state.items() if d > 0]
+            merges = [r for r in rebaseset if cl.parentrevs(r)[1] != nullrev]
+            unwantedrevs = list(repo.revs('%ld - (::%ld) - %ld',
+                                          siderevs, merges, rebaseset))
+
+            # For revs not covered, it is worth a warning.
+            if unwantedrevs:
+                repo.ui.warn(
+                    _('warning: rebasing %d:%s may include unwanted changes '
+                      'from %s\n')
+                    % (rev, repo[rev], ', '.join('%d:%s' % (r, repo[r])
+                                                 for r in unwantedrevs)))
+
+    return newps[0], newps[1], base
 
 def isagitpatch(repo, patchname):
     'Return true if the given patch is in git format'
     mqpatch = os.path.join(repo.mq.path, patchname)
     for line in patch.linereader(file(mqpatch, 'rb')):
         if line.startswith('diff --git'):
             return True
     return False
 
 def updatemq(repo, state, skipped, **opts):
     'Update rebased mq patches - finalize and then import them'
     mqrebase = {}
     mq = repo.mq
     original_series = mq.fullseries[:]
     skippedpatches = set()
 
     for p in mq.applied:
         rev = repo[p.node].rev()
         if rev in state:
             repo.ui.debug('revision %d is an mq patch (%s), finalize it.\n' %
                                         (rev, p.name))
             mqrebase[rev] = (p.name, isagitpatch(repo, p.name))
         else:
             # Applied but not rebased, not sure this should happen
             skippedpatches.add(p.name)
 
     if mqrebase:
         mq.finish(repo, mqrebase.keys())
 
         # We must start import from the newest revision
         for rev in sorted(mqrebase, reverse=True):
             if rev not in skipped:
                 name, isgit = mqrebase[rev]
                 repo.ui.note(_('updating mq patch %s to %s:%s\n') %
                              (name, state[rev], repo[state[rev]]))
                 mq.qimport(repo, (), patchname=name, git=isgit,
                                 rev=[str(state[rev])])
             else:
                 # Rebased and skipped
                 skippedpatches.add(mqrebase[rev][0])
 
         # Patches were either applied and rebased and imported in
         # order, applied and removed or unapplied. Discard the removed
         # ones while preserving the original series order and guards.
         newseries = [s for s in original_series
                      if mq.guard_re.split(s, 1)[0] not in skippedpatches]
         mq.fullseries[:] = newseries
         mq.seriesdirty = True
         mq.savedirty()
 
 def storecollapsemsg(repo, collapsemsg):
     'Store the collapse message to allow recovery'
     collapsemsg = collapsemsg or ''
     f = repo.vfs("last-message.txt", "w")
     f.write("%s\n" % collapsemsg)
     f.close()
 
 def clearcollapsemsg(repo):
     'Remove collapse message file'
     repo.vfs.unlinkpath("last-message.txt", ignoremissing=True)
 
 def restorecollapsemsg(repo, isabort):
     'Restore previously stored collapse message'
     try:
         f = repo.vfs("last-message.txt")
         collapsemsg = f.readline().strip()
         f.close()
     except IOError as err:
         if err.errno != errno.ENOENT:
             raise
         if isabort:
             # Oh well, just abort like normal
             collapsemsg = ''
         else:
             raise error.Abort(_('missing .hg/last-message.txt for rebase'))
     return collapsemsg
 
 def clearstatus(repo):
     'Remove the status files'
     _clearrebasesetvisibiliy(repo)
     # Make sure the active transaction won't write the state file
     tr = repo.currenttransaction()
     if tr:
         tr.removefilegenerator('rebasestate')
     repo.vfs.unlinkpath("rebasestate", ignoremissing=True)
 
 def needupdate(repo, state):
     '''check whether we should `update --clean` away from a merge, or if
     somehow the working dir got forcibly updated, e.g. by older hg'''
     parents = [p.rev() for p in repo[None].parents()]
 
     # Are we in a merge state at all?
     if len(parents) < 2:
         return False
 
     # We should be standing on the first as-of-yet unrebased commit.
     firstunrebased = min([old for old, new in state.iteritems()
                           if new == nullrev])
     if firstunrebased in parents:
         return True
 
     return False
 
 def abort(repo, originalwd, dest, state, activebookmark=None):
     '''Restore the repository to its original state.  Additional args:
 
     activebookmark: the name of the bookmark that should be active after the
         restore'''
 
     try:
         # If the first commits in the rebased set get skipped during the rebase,
         # their values within the state mapping will be the dest rev id. The
         # dstates list must must not contain the dest rev (issue4896)
         dstates = [s for s in state.values() if s >= 0 and s != dest]
         immutable = [d for d in dstates if not repo[d].mutable()]
         cleanup = True
         if immutable:
             repo.ui.warn(_("warning: can't clean up public changesets %s\n")
                         % ', '.join(str(repo[r]) for r in immutable),
                         hint=_("see 'hg help phases' for details"))
             cleanup = False
 
         descendants = set()
         if dstates:
             descendants = set(repo.changelog.descendants(dstates))
         if descendants - set(dstates):
             repo.ui.warn(_("warning: new changesets detected on destination "
                            "branch, can't strip\n"))
             cleanup = False
 
         if cleanup:
             shouldupdate = False
             rebased = filter(lambda x: x >= 0 and x != dest, state.values())
             if rebased:
                 strippoints = [
                         c.node() for c in repo.set('roots(%ld)', rebased)]
 
             updateifonnodes = set(rebased)
             updateifonnodes.add(dest)
             updateifonnodes.add(originalwd)
             shouldupdate = repo['.'].rev() in updateifonnodes
 
             # Update away from the rebase if necessary
             if shouldupdate or needupdate(repo, state):
                 mergemod.update(repo, originalwd, False, True)
 
             # Strip from the first rebased revision
             if rebased:
                 # no backup of rebased cset versions needed
                 repair.strip(repo.ui, repo, strippoints)
 
         if activebookmark and activebookmark in repo._bookmarks:
             bookmarks.activate(repo, activebookmark)
 
     finally:
         clearstatus(repo)
         clearcollapsemsg(repo)
         repo.ui.warn(_('rebase aborted\n'))
     return 0
 
 def buildstate(repo, dest, rebaseset, collapse, obsoletenotrebased):
     '''Define which revisions are going to be rebased and where
 
     repo: repo
     dest: context
     rebaseset: set of rev
     '''
     originalwd = repo['.'].rev()
     _setrebasesetvisibility(repo, set(rebaseset) | {originalwd})
 
     # This check isn't strictly necessary, since mq detects commits over an
     # applied patch. But it prevents messing up the working directory when
     # a partially completed rebase is blocked by mq.
     if 'qtip' in repo.tags() and (dest.node() in
                             [s.node for s in repo.mq.applied]):
         raise error.Abort(_('cannot rebase onto an applied mq patch'))
 
     roots = list(repo.set('roots(%ld)', rebaseset))
     if not roots:
         raise error.Abort(_('no matching revisions'))
     roots.sort()
     state = dict.fromkeys(rebaseset, revtodo)
     detachset = set()
     emptyrebase = True
     for root in roots:
         commonbase = root.ancestor(dest)
         if commonbase == root:
             raise error.Abort(_('source is ancestor of destination'))
         if commonbase == dest:
             wctx = repo[None]
             if dest == wctx.p1():
                 # when rebasing to '.', it will use the current wd branch name
                 samebranch = root.branch() == wctx.branch()
             else:
                 samebranch = root.branch() == dest.branch()
             if not collapse and samebranch and dest in root.parents():
                 # mark the revision as done by setting its new revision
                 # equal to its old (current) revisions
                 state[root.rev()] = root.rev()
                 repo.ui.debug('source is a child of destination\n')
                 continue
 
         emptyrebase = False
         repo.ui.debug('rebase onto %s starting from %s\n' % (dest, root))
         # Rebase tries to turn <dest> into a parent of <root> while
         # preserving the number of parents of rebased changesets:
         #
         # - A changeset with a single parent will always be rebased as a
         #   changeset with a single parent.
         #
         # - A merge will be rebased as merge unless its parents are both
         #   ancestors of <dest> or are themselves in the rebased set and
         #   pruned while rebased.
         #
         # If one parent of <root> is an ancestor of <dest>, the rebased
         # version of this parent will be <dest>. This is always true with
         # --base option.
         #
         # Otherwise, we need to *replace* the original parents with
         # <dest>. This "detaches" the rebased set from its former location
         # and rebases it onto <dest>. Changes introduced by ancestors of
         # <root> not common with <dest> (the detachset, marked as
         # nullmerge) are "removed" from the rebased changesets.
         #
         # - If <root> has a single parent, set it to <dest>.
         #
         # - If <root> is a merge, we cannot decide which parent to
         #   replace, the rebase operation is not clearly defined.
         #
         # The table below sums up this behavior:
         #
         # +------------------+----------------------+-------------------------+
         # |                  |     one parent       |  merge                  |
         # +------------------+----------------------+-------------------------+
         # | parent in        | new parent is <dest> | parents in ::<dest> are |
         # | ::<dest>         |                      | remapped to <dest>      |
         # +------------------+----------------------+-------------------------+
         # | unrelated source | new parent is <dest> | ambiguous, abort        |
         # +------------------+----------------------+-------------------------+
         #
         # The actual abort is handled by `defineparents`
         if len(root.parents()) <= 1:
             # ancestors of <root> not ancestors of <dest>
             detachset.update(repo.changelog.findmissingrevs([commonbase.rev()],
                                                             [root.rev()]))
     if emptyrebase:
         return None
     for rev in sorted(state):
         parents = [p for p in repo.changelog.parentrevs(rev) if p != nullrev]
         # if all parents of this revision are done, then so is this revision
         if parents and all((state.get(p) == p for p in parents)):
             state[rev] = rev
     for r in detachset:
         if r not in state:
             state[r] = nullmerge
     if len(roots) > 1:
         # If we have multiple roots, we may have "hole" in the rebase set.
         # Rebase roots that descend from those "hole" should not be detached as
         # other root are. We use the special `revignored` to inform rebase that
         # the revision should be ignored but that `defineparents` should search
         # a rebase destination that make sense regarding rebased topology.
         rebasedomain = set(repo.revs('%ld::%ld', rebaseset, rebaseset))
         for ignored in set(rebasedomain) - set(rebaseset):
             state[ignored] = revignored
     for r in obsoletenotrebased:
         if obsoletenotrebased[r] is None:
             state[r] = revpruned
         else:
             state[r] = revprecursor
     return originalwd, dest.rev(), state
 
 def clearrebased(ui, repo, dest, state, skipped, collapsedas=None):
     """dispose of rebased revision at the end of the rebase
 
     If `collapsedas` is not None, the rebase was a collapse whose result if the
     `collapsedas` node."""
     tonode = repo.changelog.node
     # Move bookmark of skipped nodes to destination. This cannot be handled
     # by scmutil.cleanupnodes since it will treat rev as removed (no successor)
     # and move bookmark backwards.
     bmchanges = [(name, tonode(max(adjustdest(repo, rev, dest, state))))
                  for rev in skipped
                  for name in repo.nodebookmarks(tonode(rev))]
     if bmchanges:
         with repo.transaction('rebase') as tr:
             repo._bookmarks.applychanges(repo, tr, bmchanges)
     mapping = {}
     for rev, newrev in sorted(state.items()):
         if newrev >= 0 and newrev != rev:
             if rev in skipped:
                 succs = ()
             elif collapsedas is not None:
                 succs = (collapsedas,)
             else:
                 succs = (tonode(newrev),)
             mapping[tonode(rev)] = succs
     scmutil.cleanupnodes(repo, mapping, 'rebase')
 
 def pullrebase(orig, ui, repo, *args, **opts):
     'Call rebase after pull if the latter has been invoked with --rebase'
     ret = None
     if opts.get('rebase'):
         if ui.configbool('commands', 'rebase.requiredest'):
             msg = _('rebase destination required by configuration')
             hint = _('use hg pull followed by hg rebase -d DEST')
             raise error.Abort(msg, hint=hint)
 
         with repo.wlock(), repo.lock():
             if opts.get('update'):
                 del opts['update']
                 ui.debug('--update and --rebase are not compatible, ignoring '
                          'the update flag\n')
 
             cmdutil.checkunfinished(repo)
             cmdutil.bailifchanged(repo, hint=_('cannot pull with rebase: '
                 'please commit or shelve your changes first'))
 
             revsprepull = len(repo)
             origpostincoming = commands.postincoming
             def _dummy(*args, **kwargs):
                 pass
             commands.postincoming = _dummy
             try:
                 ret = orig(ui, repo, *args, **opts)
             finally:
                 commands.postincoming = origpostincoming
             revspostpull = len(repo)
             if revspostpull > revsprepull:
                 # --rev option from pull conflict with rebase own --rev
                 # dropping it
                 if 'rev' in opts:
                     del opts['rev']
                 # positional argument from pull conflicts with rebase's own
                 # --source.
                 if 'source' in opts:
                     del opts['source']
                 # revsprepull is the len of the repo, not revnum of tip.
                 destspace = list(repo.changelog.revs(start=revsprepull))
                 opts['_destspace'] = destspace
                 try:
                     rebase(ui, repo, **opts)
                 except error.NoMergeDestAbort:
                     # we can maybe update instead
                     rev, _a, _b = destutil.destupdate(repo)
                     if rev == repo['.'].rev():
                         ui.status(_('nothing to rebase\n'))
                     else:
                         ui.status(_('nothing to rebase - updating instead\n'))
                         # not passing argument to get the bare update behavior
                         # with warning and trumpets
                         commands.update(ui, repo)
     else:
         if opts.get('tool'):
             raise error.Abort(_('--tool can only be used with --rebase'))
         ret = orig(ui, repo, *args, **opts)
 
     return ret
 
 def _setrebasesetvisibility(repo, revs):
     """store the currently rebased set on the repo object
 
     This is used by another function to prevent rebased revision to because
     hidden (see issue4504)"""
     repo = repo.unfiltered()
     repo._rebaseset = revs
     # invalidate cache if visibility changes
     hiddens = repo.filteredrevcache.get('visible', set())
     if revs & hiddens:
         repo.invalidatevolatilesets()
 
 def _clearrebasesetvisibiliy(repo):
     """remove rebaseset data from the repo"""
     repo = repo.unfiltered()
     if '_rebaseset' in vars(repo):
         del repo._rebaseset
 
 def _rebasedvisible(orig, repo):
     """ensure rebased revs stay visible (see issue4504)"""
     blockers = orig(repo)
     blockers.update(getattr(repo, '_rebaseset', ()))
     return blockers
 
 def _filterobsoleterevs(repo, revs):
     """returns a set of the obsolete revisions in revs"""
     return set(r for r in revs if repo[r].obsolete())
 
 def _computeobsoletenotrebased(repo, rebaseobsrevs, dest):
     """return a mapping obsolete => successor for all obsolete nodes to be
     rebased that have a successors in the destination
 
     obsolete => None entries in the mapping indicate nodes with no successor"""
     obsoletenotrebased = {}
 
     # Build a mapping successor => obsolete nodes for the obsolete
     # nodes to be rebased
     allsuccessors = {}
     cl = repo.changelog
     for r in rebaseobsrevs:
         node = cl.node(r)
         for s in obsutil.allsuccessors(repo.obsstore, [node]):
             try:
                 allsuccessors[cl.rev(s)] = cl.rev(node)
             except LookupError:
                 pass
 
     if allsuccessors:
         # Look for successors of obsolete nodes to be rebased among
         # the ancestors of dest
         ancs = cl.ancestors([dest],
                             stoprev=min(allsuccessors),
                             inclusive=True)
         for s in allsuccessors:
             if s in ancs:
                 obsoletenotrebased[allsuccessors[s]] = s
             elif (s == allsuccessors[s] and
                   allsuccessors.values().count(s) == 1):
                 # plain prune
                 obsoletenotrebased[s] = None
 
     return obsoletenotrebased
 
 def summaryhook(ui, repo):
     if not repo.vfs.exists('rebasestate'):
         return
     try:
         rbsrt = rebaseruntime(repo, ui, {})
         rbsrt.restorestatus()
         state = rbsrt.state
     except error.RepoLookupError:
         # i18n: column positioning for "hg summary"
         msg = _('rebase: (use "hg rebase --abort" to clear broken state)\n')
         ui.write(msg)
         return
     numrebased = len([i for i in state.itervalues() if i >= 0])
     # i18n: column positioning for "hg summary"
     ui.write(_('rebase: %s, %s (rebase --continue)\n') %
              (ui.label(_('%d rebased'), 'rebase.rebased') % numrebased,
               ui.label(_('%d remaining'), 'rebase.remaining') %
               (len(state) - numrebased)))
 
 def uisetup(ui):
     #Replace pull with a decorator to provide --rebase option
     entry = extensions.wrapcommand(commands.table, 'pull', pullrebase)
     entry[1].append(('', 'rebase', None,
                      _("rebase working directory to branch head")))
     entry[1].append(('t', 'tool', '',
                      _("specify merge tool for rebase")))
     cmdutil.summaryhooks.add('rebase', summaryhook)
     cmdutil.unfinishedstates.append(
         ['rebasestate', False, False, _('rebase in progress'),
          _("use 'hg rebase --continue' or 'hg rebase --abort'")])
     cmdutil.afterresolvedstates.append(
         ['rebasestate', _('hg rebase --continue')])
     # ensure rebased rev are not hidden
     extensions.wrapfunction(repoview, 'pinnedrevs', _rebasedvisible)

tests/test-rebase-brute-force.t

@@ -1,55 +1,55 b''
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > drawdag=$TESTDIR/drawdag.py
   > bruterebase=$TESTDIR/bruterebase.py
   > [experimental]
   > evolution=createmarkers,allowunstable
   > EOF
   $ init() {
   >   N=`expr ${N:-0} + 1`
   >   cd $TESTTMP && hg init repo$N && cd repo$N
   >   hg debugdrawdag
   > }
 
 Source looks like "N"
 
   $ init <<'EOS'
   > C D
   > |\|
   > A B Z
   > EOS
 
   $ hg debugbruterebase 'all()-Z' Z
      A: A':Z
      B: B':Z
     AB: A':Z B':Z
      C: ABORT: cannot use revision 3 as base, result would have 3 parents
     AC: A':Z C':A'B
     BC: B':Z C':B'A
    ABC: A':Z B':Z C':A'B'
      D: D':Z
     AD: A':Z D':Z
     BD: B':Z D':B'
    ABD: A':Z B':Z D':B'
-    CD: CRASH: revlog index out of range
-   ACD: A':Z C':A'A' D':Z
+    CD: ABORT: cannot use revision 3 as base, result would have 3 parents
+   ACD: A':Z C':A'B D':Z
    BCD: B':Z C':B'A D':B'
   ABCD: A':Z B':Z C':A'B' D':B'
 
 Moving backwards
 
   $ init <<'EOS'
   > C
   > |\
   > A B
   > |
   > Z
   > EOS
   $ hg debugbruterebase 'all()-Z' Z
     B: B':Z
     A: 
    BA: B':Z
     C: ABORT: cannot use revision 3 as base, result would have 3 parents
    BC: B':Z C':B'A
    AC: 
-  BAC: ABORT: nothing to merge
+  BAC: B':Z C':B'A

tests/test-rebase-newancestor.t

@@ -1,336 +1,434 b''
   $ cat >> $HGRCPATH <<EOF
   > [format]
   > usegeneraldelta=yes
   > [extensions]
   > rebase=
-  > 
+  > drawdag=$TESTDIR/drawdag.py
   > [alias]
   > tglog = log -G --template "{rev}: '{desc}' {branches}\n"
   > EOF
 
   $ hg init repo
   $ cd repo
 
   $ echo A > a
   $ echo >> a
   $ hg ci -Am A
   adding a
 
   $ echo B > a
   $ echo >> a
   $ hg ci -m B
 
   $ echo C > a
   $ echo >> a
   $ hg ci -m C
 
   $ hg up -q -C 0
 
   $ echo D >> a
   $ hg ci -Am AD
   created new head
 
   $ hg tglog
   @  3: 'AD'
   |
   | o  2: 'C'
   | |
   | o  1: 'B'
   |/
   o  0: 'A'
   
   $ hg rebase -s 1 -d 3
   rebasing 1:0f4f7cb4f549 "B"
   merging a
   rebasing 2:30ae917c0e4f "C"
   merging a
   saved backup bundle to $TESTTMP/repo/.hg/strip-backup/0f4f7cb4f549-82b3b163-rebase.hg (glob)
 
   $ hg tglog
   o  3: 'C'
   |
   o  2: 'B'
   |
   @  1: 'AD'
   |
   o  0: 'A'
   
 
   $ cd ..
 
 
 Test rebasing of merges with ancestors of the rebase destination - a situation
 that often happens when trying to recover from repeated merging with a mainline
 branch.
 
 The test case creates a dev branch that contains a couple of merges from the
 default branch. When rebasing to the default branch, these merges would be
 merges with ancestors on the same branch. The merges _could_ contain some
 interesting conflict resolutions or additional changes in the merge commit, but
 that is mixed up with the actual merge stuff and there is in general no way to
 separate them.
 
 Note: The dev branch contains _no_ changes to f-default. It might be unclear
 how rebasing of ancestor merges should be handled, but the current behavior
 with spurious prompts for conflicts in files that didn't change seems very
 wrong.
 
   $ hg init ancestor-merge
   $ cd ancestor-merge
 
   $ touch f-default
   $ hg ci -Aqm 'default: create f-default'
 
   $ hg branch -q dev
   $ hg ci -qm 'dev: create branch'
 
   $ echo stuff > f-dev
   $ hg ci -Aqm 'dev: f-dev stuff'
 
   $ hg up -q default
   $ echo stuff > f-default
   $ hg ci -m 'default: f-default stuff'
 
   $ hg up -q dev
   $ hg merge -q default
   $ hg ci -m 'dev: merge default'
 
   $ hg up -q default
   $ hg rm f-default
   $ hg ci -m 'default: remove f-default'
 
   $ hg up -q dev
   $ hg merge -q default
   $ hg ci -m 'dev: merge default'
 
   $ hg up -q default
   $ echo stuff > f-other
   $ hg ci -Aqm 'default: f-other stuff'
 
   $ hg tglog
   @  7: 'default: f-other stuff'
   |
   | o  6: 'dev: merge default' dev
   |/|
   o |  5: 'default: remove f-default'
   | |
   | o  4: 'dev: merge default' dev
   |/|
   o |  3: 'default: f-default stuff'
   | |
   | o  2: 'dev: f-dev stuff' dev
   | |
   | o  1: 'dev: create branch' dev
   |/
   o  0: 'default: create f-default'
   
   $ hg clone -qU . ../ancestor-merge-2
 
 Full rebase all the way back from branching point:
 
   $ hg rebase -r 'only(dev,default)' -d default --config ui.interactive=True << EOF
   > c
   > EOF
   rebasing 1:1d1a643d390e "dev: create branch"
   note: rebase of 1:1d1a643d390e created no changes to commit
   rebasing 2:ec2c14fb2984 "dev: f-dev stuff"
   rebasing 4:4b019212aaf6 "dev: merge default"
   other [source] changed f-default which local [dest] deleted
   use (c)hanged version, leave (d)eleted, or leave (u)nresolved? c
   rebasing 6:9455ee510502 "dev: merge default"
   saved backup bundle to $TESTTMP/ancestor-merge/.hg/strip-backup/1d1a643d390e-43e9e04b-rebase.hg (glob)
   $ hg tglog
   o  6: 'dev: merge default'
   |
   o  5: 'dev: merge default'
   |
   o  4: 'dev: f-dev stuff'
   |
   @  3: 'default: f-other stuff'
   |
   o  2: 'default: remove f-default'
   |
   o  1: 'default: f-default stuff'
   |
   o  0: 'default: create f-default'
   
 Grafty cherry picking rebasing:
 
   $ cd ../ancestor-merge-2
 
   $ hg phase -fdr0:
   $ hg rebase -r 'children(only(dev,default))' -d default --config ui.interactive=True << EOF
   > c
   > EOF
   rebasing 2:ec2c14fb2984 "dev: f-dev stuff"
   rebasing 4:4b019212aaf6 "dev: merge default"
   other [source] changed f-default which local [dest] deleted
   use (c)hanged version, leave (d)eleted, or leave (u)nresolved? c
   rebasing 6:9455ee510502 "dev: merge default"
   saved backup bundle to $TESTTMP/ancestor-merge-2/.hg/strip-backup/ec2c14fb2984-62d0b222-rebase.hg (glob)
   $ hg tglog
   o  7: 'dev: merge default'
   |
   o  6: 'dev: merge default'
   |
   o  5: 'dev: f-dev stuff'
   |
   o  4: 'default: f-other stuff'
   |
   o  3: 'default: remove f-default'
   |
   o  2: 'default: f-default stuff'
   |
   | o  1: 'dev: create branch' dev
   |/
   o  0: 'default: create f-default'
   
   $ cd ..
 
 
 Test order of parents of rebased merged with un-rebased changes as p1.
 
   $ hg init parentorder
   $ cd parentorder
   $ touch f
   $ hg ci -Aqm common
   $ touch change
   $ hg ci -Aqm change
   $ touch target
   $ hg ci -Aqm target
   $ hg up -qr 0
   $ touch outside
   $ hg ci -Aqm outside
   $ hg merge -qr 1
   $ hg ci -m 'merge p1 3=outside p2 1=ancestor'
   $ hg par
   changeset:   4:6990226659be
   tag:         tip
   parent:      3:f59da8fc0fcf
   parent:      1:dd40c13f7a6f
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge p1 3=outside p2 1=ancestor
   
   $ hg up -qr 1
   $ hg merge -qr 3
   $ hg ci -qm 'merge p1 1=ancestor p2 3=outside'
   $ hg par
   changeset:   5:a57575f79074
   tag:         tip
   parent:      1:dd40c13f7a6f
   parent:      3:f59da8fc0fcf
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge p1 1=ancestor p2 3=outside
   
   $ hg tglog
   @    5: 'merge p1 1=ancestor p2 3=outside'
   |\
   +---o  4: 'merge p1 3=outside p2 1=ancestor'
   | |/
   | o  3: 'outside'
   | |
   +---o  2: 'target'
   | |
   o |  1: 'change'
   |/
   o  0: 'common'
   
   $ hg rebase -r 4 -d 2
   rebasing 4:6990226659be "merge p1 3=outside p2 1=ancestor"
   saved backup bundle to $TESTTMP/parentorder/.hg/strip-backup/6990226659be-4d67a0d3-rebase.hg (glob)
   $ hg tip
   changeset:   5:cca50676b1c5
   tag:         tip
   parent:      2:a60552eb93fb
   parent:      3:f59da8fc0fcf
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge p1 3=outside p2 1=ancestor
   
   $ hg rebase -r 4 -d 2
   rebasing 4:a57575f79074 "merge p1 1=ancestor p2 3=outside"
   saved backup bundle to $TESTTMP/parentorder/.hg/strip-backup/a57575f79074-385426e5-rebase.hg (glob)
   $ hg tip
   changeset:   5:f9daf77ffe76
   tag:         tip
   parent:      2:a60552eb93fb
   parent:      3:f59da8fc0fcf
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge p1 1=ancestor p2 3=outside
   
   $ hg tglog
   @    5: 'merge p1 1=ancestor p2 3=outside'
   |\
   +---o  4: 'merge p1 3=outside p2 1=ancestor'
   | |/
   | o  3: 'outside'
   | |
   o |  2: 'target'
   | |
   o |  1: 'change'
   |/
   o  0: 'common'
   
 rebase of merge of ancestors
 
   $ hg up -qr 2
   $ hg merge -qr 3
   $ echo 'other change while merging future "rebase ancestors"' > other
   $ hg ci -Aqm 'merge rebase ancestors'
   $ hg rebase -d 5 -v
   rebasing 6:4c5f12f25ebe "merge rebase ancestors" (tip)
   resolving manifests
   removing other
   note: merging f9daf77ffe76+ and 4c5f12f25ebe using bids from ancestors a60552eb93fb and f59da8fc0fcf
   
   calculating bids for ancestor a60552eb93fb
   resolving manifests
   
   calculating bids for ancestor f59da8fc0fcf
   resolving manifests
   
   auction for merging merge bids
    other: consensus for g
   end of auction
   
   getting other
   committing files:
   other
   committing manifest
   committing changelog
   rebase merging completed
   1 changesets found
   uncompressed size of bundle content:
        199 (changelog)
        216 (manifests)
        182  other
   saved backup bundle to $TESTTMP/parentorder/.hg/strip-backup/4c5f12f25ebe-f46990e5-rebase.hg (glob)
   1 changesets found
   uncompressed size of bundle content:
        254 (changelog)
        167 (manifests)
        182  other
   adding branch
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   rebase completed
   $ hg tglog
   @  6: 'merge rebase ancestors'
   |
   o    5: 'merge p1 1=ancestor p2 3=outside'
   |\
   +---o  4: 'merge p1 3=outside p2 1=ancestor'
   | |/
   | o  3: 'outside'
   | |
   o |  2: 'target'
   | |
   o |  1: 'change'
   |/
   o  0: 'common'
   
+Due to the limitation of 3-way merge algorithm (1 merge base), rebasing a merge
+may include unwanted content:
+
+  $ hg init $TESTTMP/dual-merge-base1
+  $ cd $TESTTMP/dual-merge-base1
+  $ hg debugdrawdag <<'EOS'
+  >   F
+  >  /|
+  > D E
+  > | |
+  > B C
+  > |/
+  > A Z
+  > |/
+  > R
+  > EOS
+  $ hg rebase -r D+E+F -d Z
+  rebasing 5:5f2c926dfecf "D" (D)
+  rebasing 6:b296604d9846 "E" (E)
+  rebasing 7:caa9781e507d "F" (F tip)
+  warning: rebasing 7:caa9781e507d may include unwanted changes from 4:d6003a550c2c
+  saved backup bundle to $TESTTMP/dual-merge-base1/.hg/strip-backup/b296604d9846-0516f6d2-rebase.hg (glob)
+  $ hg log -r 4 -T '{files}\n'
+  C
+  $ hg manifest -r 'desc(F)'
+  C
+  D
+  E
+  R
+  Z
+
+The warning does not get printed if there is no unwanted change detected:
+
+  $ hg init $TESTTMP/dual-merge-base2
+  $ cd $TESTTMP/dual-merge-base2
+  $ hg debugdrawdag <<'EOS'
+  >   D
+  >  /|
+  > B C
+  > |/
+  > A Z
+  > |/
+  > R
+  > EOS
+  $ hg rebase -r B+C+D -d Z
+  rebasing 3:c1e6b162678d "B" (B)
+  rebasing 4:d6003a550c2c "C" (C)
+  rebasing 5:c8f78076273e "D" (D tip)
+  saved backup bundle to $TESTTMP/dual-merge-base2/.hg/strip-backup/d6003a550c2c-6f1424b6-rebase.hg (glob)
+  $ hg manifest -r 'desc(D)'
+  B
+  C
+  R
+  Z
+
+The merge base could be different from old p1 (changed parent becomes new p1):
+
+  $ hg init $TESTTMP/chosen-merge-base1
+  $ cd $TESTTMP/chosen-merge-base1
+  $ hg debugdrawdag <<'EOS'
+  >   F
+  >  /|
+  > D E
+  > | |
+  > B C Z
+  > EOS
+  $ hg rebase -r D+F -d Z
+  rebasing 3:004dc1679908 "D" (D)
+  rebasing 5:4be4cbf6f206 "F" (F tip)
+  saved backup bundle to $TESTTMP/chosen-merge-base1/.hg/strip-backup/004dc1679908-06a66a3c-rebase.hg (glob)
+  $ hg manifest -r 'desc(F)'
+  C
+  D
+  E
+  Z
+  $ hg log -r `hg log -r 'desc(F)' -T '{p1node}'` -T '{desc}\n'
+  D
+
+  $ hg init $TESTTMP/chosen-merge-base2
+  $ cd $TESTTMP/chosen-merge-base2
+  $ hg debugdrawdag <<'EOS'
+  >   F
+  >  /|
+  > D E
+  > | |
+  > B C Z
+  > EOS
+  $ hg rebase -r E+F -d Z
+  rebasing 4:974e4943c210 "E" (E)
+  rebasing 5:4be4cbf6f206 "F" (F tip)
+  saved backup bundle to $TESTTMP/chosen-merge-base2/.hg/strip-backup/974e4943c210-b2874da5-rebase.hg (glob)
+  $ hg manifest -r 'desc(F)'
+  B
+  D
+  E
+  Z
+  $ hg log -r `hg log -r 'desc(F)' -T '{p1node}'` -T '{desc}\n'
+  E

tests/test-rebase-obsolete.t

@@ -1,1158 +1,1168 b''
 ==========================
 Test rebase with obsolete
 ==========================
 
 Enable obsolete
 
   $ cat >> $HGRCPATH << EOF
   > [ui]
   > logtemplate= {rev}:{node|short} {desc|firstline}
   > [experimental]
   > stabilization=createmarkers,allowunstable
   > [phases]
   > publish=False
   > [extensions]
   > rebase=
   > drawdag=$TESTDIR/drawdag.py
   > EOF
 
 Setup rebase canonical repo
 
   $ hg init base
   $ cd base
   $ hg unbundle "$TESTDIR/bundles/rebase.hg"
   adding changesets
   adding manifests
   adding file changes
   added 8 changesets with 7 changes to 7 files (+2 heads)
   (run 'hg heads' to see heads, 'hg merge' to merge)
   $ hg up tip
   3 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg log -G
   @  7:02de42196ebe H
   |
   | o  6:eea13746799a G
   |/|
   o |  5:24b6387c8c8c F
   | |
   | o  4:9520eea781bc E
   |/
   | o  3:32af7686d403 D
   | |
   | o  2:5fddd98957c8 C
   | |
   | o  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
   $ cd ..
 
 simple rebase
 ---------------------------------
 
   $ hg clone base simple
   updating to branch default
   3 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd simple
   $ hg up 32af7686d403
   3 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ hg rebase -d eea13746799a
   rebasing 1:42ccdea3bb16 "B"
   rebasing 2:5fddd98957c8 "C"
   rebasing 3:32af7686d403 "D"
   $ hg log -G
   @  10:8eeb3c33ad33 D
   |
   o  9:2327fea05063 C
   |
   o  8:e4e5be0395b2 B
   |
   | o  7:02de42196ebe H
   | |
   o |  6:eea13746799a G
   |\|
   | o  5:24b6387c8c8c F
   | |
   o |  4:9520eea781bc E
   |/
   o  0:cd010b8cd998 A
   
   $ hg log --hidden -G
   @  10:8eeb3c33ad33 D
   |
   o  9:2327fea05063 C
   |
   o  8:e4e5be0395b2 B
   |
   | o  7:02de42196ebe H
   | |
   o |  6:eea13746799a G
   |\|
   | o  5:24b6387c8c8c F
   | |
   o |  4:9520eea781bc E
   |/
   | x  3:32af7686d403 D
   | |
   | x  2:5fddd98957c8 C
   | |
   | x  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
   $ hg debugobsolete
   42ccdea3bb16d28e1848c95fe2e44c000f3f21b1 e4e5be0395b2cbd471ed22a26b1b6a1a0658a794 0 (*) {'user': 'test'} (glob)
   5fddd98957c8a54a4d436dfe1da9d87f21a1b97b 2327fea05063f39961b14cb69435a9898dc9a245 0 (*) {'user': 'test'} (glob)
   32af7686d403cf45b5d95f2d70cebea587ac806a 8eeb3c33ad33d452c89e5dcf611c347f978fb42b 0 (*) {'user': 'test'} (glob)
 
 
   $ cd ..
 
 empty changeset
 ---------------------------------
 
   $ hg clone base empty
   updating to branch default
   3 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd empty
   $ hg up eea13746799a
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
 We make a copy of both the first changeset in the rebased and some other in the
 set.
 
   $ hg graft 42ccdea3bb16 32af7686d403
   grafting 1:42ccdea3bb16 "B"
   grafting 3:32af7686d403 "D"
   $ hg rebase  -s 42ccdea3bb16 -d .
   rebasing 1:42ccdea3bb16 "B"
   note: rebase of 1:42ccdea3bb16 created no changes to commit
   rebasing 2:5fddd98957c8 "C"
   rebasing 3:32af7686d403 "D"
   note: rebase of 3:32af7686d403 created no changes to commit
   $ hg log -G
   o  10:5ae4c968c6ac C
   |
   @  9:08483444fef9 D
   |
   o  8:8877864f1edb B
   |
   | o  7:02de42196ebe H
   | |
   o |  6:eea13746799a G
   |\|
   | o  5:24b6387c8c8c F
   | |
   o |  4:9520eea781bc E
   |/
   o  0:cd010b8cd998 A
   
   $ hg log --hidden -G
   o  10:5ae4c968c6ac C
   |
   @  9:08483444fef9 D
   |
   o  8:8877864f1edb B
   |
   | o  7:02de42196ebe H
   | |
   o |  6:eea13746799a G
   |\|
   | o  5:24b6387c8c8c F
   | |
   o |  4:9520eea781bc E
   |/
   | x  3:32af7686d403 D
   | |
   | x  2:5fddd98957c8 C
   | |
   | x  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
   $ hg debugobsolete
   42ccdea3bb16d28e1848c95fe2e44c000f3f21b1 0 {cd010b8cd998f3981a5a8115f94f8da4ab506089} (*) {'user': 'test'} (glob)
   5fddd98957c8a54a4d436dfe1da9d87f21a1b97b 5ae4c968c6aca831df823664e706c9d4aa34473d 0 (*) {'user': 'test'} (glob)
   32af7686d403cf45b5d95f2d70cebea587ac806a 0 {5fddd98957c8a54a4d436dfe1da9d87f21a1b97b} (*) {'user': 'test'} (glob)
 
 
 More complex case where part of the rebase set were already rebased
 
   $ hg rebase --rev 'desc(D)' --dest 'desc(H)'
   rebasing 9:08483444fef9 "D"
   $ hg debugobsolete
   42ccdea3bb16d28e1848c95fe2e44c000f3f21b1 0 {cd010b8cd998f3981a5a8115f94f8da4ab506089} (*) {'user': 'test'} (glob)
   5fddd98957c8a54a4d436dfe1da9d87f21a1b97b 5ae4c968c6aca831df823664e706c9d4aa34473d 0 (*) {'user': 'test'} (glob)
   32af7686d403cf45b5d95f2d70cebea587ac806a 0 {5fddd98957c8a54a4d436dfe1da9d87f21a1b97b} (*) {'user': 'test'} (glob)
   08483444fef91d6224f6655ee586a65d263ad34c 4596109a6a4328c398bde3a4a3b6737cfade3003 0 (*) {'user': 'test'} (glob)
   $ hg log -G
   @  11:4596109a6a43 D
   |
   | o  10:5ae4c968c6ac C
   | |
   | x  9:08483444fef9 D
   | |
   | o  8:8877864f1edb B
   | |
   o |  7:02de42196ebe H
   | |
   | o  6:eea13746799a G
   |/|
   o |  5:24b6387c8c8c F
   | |
   | o  4:9520eea781bc E
   |/
   o  0:cd010b8cd998 A
   
   $ hg rebase --source 'desc(B)' --dest 'tip' --config experimental.rebaseskipobsolete=True
   rebasing 8:8877864f1edb "B"
   note: not rebasing 9:08483444fef9 "D", already in destination as 11:4596109a6a43 "D"
   rebasing 10:5ae4c968c6ac "C"
   $ hg debugobsolete
   42ccdea3bb16d28e1848c95fe2e44c000f3f21b1 0 {cd010b8cd998f3981a5a8115f94f8da4ab506089} (*) {'user': 'test'} (glob)
   5fddd98957c8a54a4d436dfe1da9d87f21a1b97b 5ae4c968c6aca831df823664e706c9d4aa34473d 0 (*) {'user': 'test'} (glob)
   32af7686d403cf45b5d95f2d70cebea587ac806a 0 {5fddd98957c8a54a4d436dfe1da9d87f21a1b97b} (*) {'user': 'test'} (glob)
   08483444fef91d6224f6655ee586a65d263ad34c 4596109a6a4328c398bde3a4a3b6737cfade3003 0 (*) {'user': 'test'} (glob)
   8877864f1edb05d0e07dc4ba77b67a80a7b86672 462a34d07e599b87ea08676a449373fe4e2e1347 0 (*) {'user': 'test'} (glob)
   5ae4c968c6aca831df823664e706c9d4aa34473d 98f6af4ee9539e14da4465128f894c274900b6e5 0 (*) {'user': 'test'} (glob)
   $ hg log --rev 'contentdivergent()'
   $ hg log -G
   o  13:98f6af4ee953 C
   |
   o  12:462a34d07e59 B
   |
   @  11:4596109a6a43 D
   |
   o  7:02de42196ebe H
   |
   | o  6:eea13746799a G
   |/|
   o |  5:24b6387c8c8c F
   | |
   | o  4:9520eea781bc E
   |/
   o  0:cd010b8cd998 A
   
   $ hg log --style default --debug -r 4596109a6a4328c398bde3a4a3b6737cfade3003
   changeset:   11:4596109a6a4328c398bde3a4a3b6737cfade3003
   phase:       draft
   parent:      7:02de42196ebee42ef284b6780a87cdc96e8eaab6
   parent:      -1:0000000000000000000000000000000000000000
   manifest:    11:a91006e3a02f1edf631f7018e6e5684cf27dd905
   user:        Nicolas Dumazet <[e-mail]>
   date:        Sat Apr 30 15:24:48 2011 +0200
   files+:      D
   extra:       branch=default
   extra:       rebase_source=08483444fef91d6224f6655ee586a65d263ad34c
   extra:       source=32af7686d403cf45b5d95f2d70cebea587ac806a
   description:
   D
   
   
   $ hg up -qr 'desc(G)'
   $ hg graft 4596109a6a4328c398bde3a4a3b6737cfade3003
   grafting 11:4596109a6a43 "D"
   $ hg up -qr 'desc(E)'
   $ hg rebase -s tip -d .
   rebasing 14:9e36056a46e3 "D" (tip)
   $ hg log --style default --debug -r tip
   changeset:   15:627d4614809036ba22b9e7cb31638ddc06ab99ab
   tag:         tip
   phase:       draft
   parent:      4:9520eea781bcca16c1e15acc0ba14335a0e8e5ba
   parent:      -1:0000000000000000000000000000000000000000
   manifest:    15:648e8ede73ae3e497d093d3a4c8fcc2daa864f42
   user:        Nicolas Dumazet <[e-mail]>
   date:        Sat Apr 30 15:24:48 2011 +0200
   files+:      D
   extra:       branch=default
   extra:       intermediate-source=4596109a6a4328c398bde3a4a3b6737cfade3003
   extra:       rebase_source=9e36056a46e37c9776168c7375734eebc70e294f
   extra:       source=32af7686d403cf45b5d95f2d70cebea587ac806a
   description:
   D
   
   
 Start rebase from a commit that is obsolete but not hidden only because it's
 a working copy parent. We should be moved back to the starting commit as usual
 even though it is hidden (until we're moved there).
 
   $ hg --hidden up -qr 'first(hidden())'
   $ hg rebase --rev 13 --dest 15
   rebasing 13:98f6af4ee953 "C"
   $ hg log -G
   o  16:294a2b93eb4d C
   |
   o  15:627d46148090 D
   |
   | o  12:462a34d07e59 B
   | |
   | o  11:4596109a6a43 D
   | |
   | o  7:02de42196ebe H
   | |
   +---o  6:eea13746799a G
   | |/
   | o  5:24b6387c8c8c F
   | |
   o |  4:9520eea781bc E
   |/
   | @  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
 
   $ cd ..
 
 collapse rebase
 ---------------------------------
 
   $ hg clone base collapse
   updating to branch default
   3 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd collapse
   $ hg rebase  -s 42ccdea3bb16 -d eea13746799a --collapse
   rebasing 1:42ccdea3bb16 "B"
   rebasing 2:5fddd98957c8 "C"
   rebasing 3:32af7686d403 "D"
   $ hg log -G
   o  8:4dc2197e807b Collapsed revision
   |
   | @  7:02de42196ebe H
   | |
   o |  6:eea13746799a G
   |\|
   | o  5:24b6387c8c8c F
   | |
   o |  4:9520eea781bc E
   |/
   o  0:cd010b8cd998 A
   
   $ hg log --hidden -G
   o  8:4dc2197e807b Collapsed revision
   |
   | @  7:02de42196ebe H
   | |
   o |  6:eea13746799a G
   |\|
   | o  5:24b6387c8c8c F
   | |
   o |  4:9520eea781bc E
   |/
   | x  3:32af7686d403 D
   | |
   | x  2:5fddd98957c8 C
   | |
   | x  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
   $ hg id --debug -r tip
   4dc2197e807bae9817f09905b50ab288be2dbbcf tip
   $ hg debugobsolete
   42ccdea3bb16d28e1848c95fe2e44c000f3f21b1 4dc2197e807bae9817f09905b50ab288be2dbbcf 0 (*) {'user': 'test'} (glob)
   5fddd98957c8a54a4d436dfe1da9d87f21a1b97b 4dc2197e807bae9817f09905b50ab288be2dbbcf 0 (*) {'user': 'test'} (glob)
   32af7686d403cf45b5d95f2d70cebea587ac806a 4dc2197e807bae9817f09905b50ab288be2dbbcf 0 (*) {'user': 'test'} (glob)
 
   $ cd ..
 
 Rebase set has hidden descendants
 ---------------------------------
 
 We rebase a changeset which has a hidden changeset. The hidden changeset must
 not be rebased.
 
   $ hg clone base hidden
   updating to branch default
   3 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd hidden
   $ hg rebase -s 5fddd98957c8 -d eea13746799a
   rebasing 2:5fddd98957c8 "C"
   rebasing 3:32af7686d403 "D"
   $ hg rebase -s 42ccdea3bb16 -d 02de42196ebe
   rebasing 1:42ccdea3bb16 "B"
   $ hg log -G
   o  10:7c6027df6a99 B
   |
   | o  9:cf44d2f5a9f4 D
   | |
   | o  8:e273c5e7d2d2 C
   | |
   @ |  7:02de42196ebe H
   | |
   | o  6:eea13746799a G
   |/|
   o |  5:24b6387c8c8c F
   | |
   | o  4:9520eea781bc E
   |/
   o  0:cd010b8cd998 A
   
   $ hg log --hidden -G
   o  10:7c6027df6a99 B
   |
   | o  9:cf44d2f5a9f4 D
   | |
   | o  8:e273c5e7d2d2 C
   | |
   @ |  7:02de42196ebe H
   | |
   | o  6:eea13746799a G
   |/|
   o |  5:24b6387c8c8c F
   | |
   | o  4:9520eea781bc E
   |/
   | x  3:32af7686d403 D
   | |
   | x  2:5fddd98957c8 C
   | |
   | x  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
   $ hg debugobsolete
   5fddd98957c8a54a4d436dfe1da9d87f21a1b97b e273c5e7d2d29df783dce9f9eaa3ac4adc69c15d 0 (*) {'user': 'test'} (glob)
   32af7686d403cf45b5d95f2d70cebea587ac806a cf44d2f5a9f4297a62be94cbdd3dff7c7dc54258 0 (*) {'user': 'test'} (glob)
   42ccdea3bb16d28e1848c95fe2e44c000f3f21b1 7c6027df6a99d93f461868e5433f63bde20b6dfb 0 (*) {'user': 'test'} (glob)
 
 Test that rewriting leaving instability behind is allowed
 ---------------------------------------------------------------------
 
   $ hg log -r 'children(8)'
   9:cf44d2f5a9f4 D (no-eol)
   $ hg rebase -r 8
   rebasing 8:e273c5e7d2d2 "C"
   $ hg log -G
   o  11:0d8f238b634c C
   |
   o  10:7c6027df6a99 B
   |
   | o  9:cf44d2f5a9f4 D
   | |
   | x  8:e273c5e7d2d2 C
   | |
   @ |  7:02de42196ebe H
   | |
   | o  6:eea13746799a G
   |/|
   o |  5:24b6387c8c8c F
   | |
   | o  4:9520eea781bc E
   |/
   o  0:cd010b8cd998 A
   
 
 
 Test multiple root handling
 ------------------------------------
 
   $ hg rebase --dest 4 --rev '7+11+9'
   rebasing 9:cf44d2f5a9f4 "D"
   rebasing 7:02de42196ebe "H"
   not rebasing ignored 10:7c6027df6a99 "B"
   rebasing 11:0d8f238b634c "C" (tip)
   $ hg log -G
   o  14:1e8370e38cca C
   |
   @  13:bfe264faf697 H
   |
   | o  12:102b4c1d889b D
   |/
   | o  10:7c6027df6a99 B
   | |
   | x  7:02de42196ebe H
   | |
   +---o  6:eea13746799a G
   | |/
   | o  5:24b6387c8c8c F
   | |
   o |  4:9520eea781bc E
   |/
   o  0:cd010b8cd998 A
   
   $ cd ..
 
 Detach both parents
 
   $ hg init double-detach
   $ cd double-detach
 
   $ hg debugdrawdag <<EOF
   >   F
   >  /|
   > C E
   > | |
   > B D G
   >  \|/
   >   A
   > EOF
 
-BROKEN: This raises an exception
-  $ hg rebase -d G -r 'B + D + F' 2>&1 | grep '^AssertionError'
-  AssertionError: no base found to rebase on (defineparents called wrong)
+  $ hg rebase -d G -r 'B + D + F'
+  rebasing 1:112478962961 "B" (B)
+  rebasing 2:b18e25de2cf5 "D" (D)
+  not rebasing ignored 4:26805aba1e60 "C" (C)
+  not rebasing ignored 5:4b61ff5c62e2 "E" (E)
+  rebasing 6:f15c3adaf214 "F" (F tip)
+  abort: cannot use revision 6 as base, result would have 3 parents
+  [255]
 
   $ cd ..
 
 test on rebase dropping a merge
 
 (setup)
 
   $ hg init dropmerge
   $ cd dropmerge
   $ hg unbundle "$TESTDIR/bundles/rebase.hg"
   adding changesets
   adding manifests
   adding file changes
   added 8 changesets with 7 changes to 7 files (+2 heads)
   (run 'hg heads' to see heads, 'hg merge' to merge)
   $ hg up 3
   4 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 7
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m 'M'
   $ echo I > I
   $ hg add I
   $ hg ci -m I
   $ hg log -G
   @  9:4bde274eefcf I
   |
   o    8:53a6a128b2b7 M
   |\
   | o  7:02de42196ebe H
   | |
   | | o  6:eea13746799a G
   | |/|
   | o |  5:24b6387c8c8c F
   | | |
   | | o  4:9520eea781bc E
   | |/
   o |  3:32af7686d403 D
   | |
   o |  2:5fddd98957c8 C
   | |
   o |  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
 (actual test)
 
   $ hg rebase --dest 6 --rev '((desc(H) + desc(D))::) - desc(M)'
   rebasing 3:32af7686d403 "D"
   rebasing 7:02de42196ebe "H"
   not rebasing ignored 8:53a6a128b2b7 "M"
   rebasing 9:4bde274eefcf "I" (tip)
   $ hg log -G
   @  12:acd174b7ab39 I
   |
   o  11:6c11a6218c97 H
   |
   | o  10:b5313c85b22e D
   |/
   | o    8:53a6a128b2b7 M
   | |\
   | | x  7:02de42196ebe H
   | | |
   o---+  6:eea13746799a G
   | | |
   | | o  5:24b6387c8c8c F
   | | |
   o---+  4:9520eea781bc E
    / /
   x |  3:32af7686d403 D
   | |
   o |  2:5fddd98957c8 C
   | |
   o |  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
 
 Test hidden changesets in the rebase set (issue4504)
 
   $ hg up --hidden 9
   3 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo J > J
   $ hg add J
   $ hg commit -m J
   $ hg debugobsolete `hg log --rev . -T '{node}'`
   obsoleted 1 changesets
 
   $ hg rebase --rev .~1::. --dest 'max(desc(D))' --traceback --config experimental.rebaseskipobsolete=off
   rebasing 9:4bde274eefcf "I"
   rebasing 13:06edfc82198f "J" (tip)
   $ hg log -G
   @  15:5ae8a643467b J
   |
   o  14:9ad579b4a5de I
   |
   | o  12:acd174b7ab39 I
   | |
   | o  11:6c11a6218c97 H
   | |
   o |  10:b5313c85b22e D
   |/
   | o    8:53a6a128b2b7 M
   | |\
   | | x  7:02de42196ebe H
   | | |
   o---+  6:eea13746799a G
   | | |
   | | o  5:24b6387c8c8c F
   | | |
   o---+  4:9520eea781bc E
    / /
   x |  3:32af7686d403 D
   | |
   o |  2:5fddd98957c8 C
   | |
   o |  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
   $ hg up 14 -C
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo "K" > K
   $ hg add K
   $ hg commit --amend -m "K"
   $ echo "L" > L
   $ hg add L
   $ hg commit -m "L"
   $ hg up '.^'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo "M" > M
   $ hg add M
   $ hg commit --amend -m "M"
   $ hg log -G
   @  20:bfaedf8eb73b M
   |
   | o  18:97219452e4bd L
   | |
   | x  17:fc37a630c901 K
   |/
   | o  15:5ae8a643467b J
   | |
   | x  14:9ad579b4a5de I
   |/
   | o  12:acd174b7ab39 I
   | |
   | o  11:6c11a6218c97 H
   | |
   o |  10:b5313c85b22e D
   |/
   | o    8:53a6a128b2b7 M
   | |\
   | | x  7:02de42196ebe H
   | | |
   o---+  6:eea13746799a G
   | | |
   | | o  5:24b6387c8c8c F
   | | |
   o---+  4:9520eea781bc E
    / /
   x |  3:32af7686d403 D
   | |
   o |  2:5fddd98957c8 C
   | |
   o |  1:42ccdea3bb16 B
   |/
   o  0:cd010b8cd998 A
   
   $ hg rebase -s 14 -d 18 --config experimental.rebaseskipobsolete=True
   note: not rebasing 14:9ad579b4a5de "I", already in destination as 17:fc37a630c901 "K"
   rebasing 15:5ae8a643467b "J"
 
   $ cd ..
 
 Skip obsolete changeset even with multiple hops
 -----------------------------------------------
 
 setup
 
   $ hg init obsskip
   $ cd obsskip
   $ cat << EOF >> .hg/hgrc
   > [experimental]
   > rebaseskipobsolete = True
   > [extensions]
   > strip =
   > EOF
   $ echo A > A
   $ hg add A
   $ hg commit -m A
   $ echo B > B
   $ hg add B
   $ hg commit -m B0
   $ hg commit --amend -m B1
   $ hg commit --amend -m B2
   $ hg up --hidden 'desc(B0)'
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo C > C
   $ hg add C
   $ hg commit -m C
 
 Rebase finds its way in a chain of marker
 
   $ hg rebase -d 'desc(B2)'
   note: not rebasing 1:a8b11f55fb19 "B0", already in destination as 3:261e70097290 "B2"
   rebasing 4:212cb178bcbb "C" (tip)
 
 Even when the chain include missing node
 
   $ hg up --hidden 'desc(B0)'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo D > D
   $ hg add D
   $ hg commit -m D
   $ hg --hidden strip -r 'desc(B1)'
   saved backup bundle to $TESTTMP/obsskip/.hg/strip-backup/86f6414ccda7-b1c452ee-backup.hg (glob)
 
   $ hg rebase -d 'desc(B2)'
   note: not rebasing 1:a8b11f55fb19 "B0", already in destination as 2:261e70097290 "B2"
   rebasing 5:1a79b7535141 "D" (tip)
   $ hg up 4
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo "O" > O
   $ hg add O
   $ hg commit -m O
   $ echo "P" > P
   $ hg add P
   $ hg commit -m P
   $ hg log -G
   @  8:8d47583e023f P
   |
   o  7:360bbaa7d3ce O
   |
   | o  6:9c48361117de D
   | |
   o |  4:ff2c4d47b71d C
   |/
   o  2:261e70097290 B2
   |
   o  0:4a2df7238c3b A
   
   $ hg debugobsolete `hg log -r 7 -T '{node}\n'` --config experimental.stabilization=all
   obsoleted 1 changesets
   $ hg rebase -d 6 -r "4::"
   rebasing 4:ff2c4d47b71d "C"
   note: not rebasing 7:360bbaa7d3ce "O", it has no successor
   rebasing 8:8d47583e023f "P" (tip)
 
 If all the changeset to be rebased are obsolete and present in the destination, we
 should display a friendly error message
 
   $ hg log -G
   @  10:121d9e3bc4c6 P
   |
   o  9:4be60e099a77 C
   |
   o  6:9c48361117de D
   |
   o  2:261e70097290 B2
   |
   o  0:4a2df7238c3b A
   
 
   $ hg up 9
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo "non-relevant change" > nonrelevant
   $ hg add nonrelevant
   $ hg commit -m nonrelevant
   created new head
   $ hg debugobsolete `hg log -r 11 -T '{node}\n'` --config experimental.stabilization=all
   obsoleted 1 changesets
   $ hg rebase -r . -d 10
   note: not rebasing 11:f44da1f4954c "nonrelevant" (tip), it has no successor
 
 If a rebase is going to create divergence, it should abort
 
   $ hg log -G
   @  11:f44da1f4954c nonrelevant
   |
   | o  10:121d9e3bc4c6 P
   |/
   o  9:4be60e099a77 C
   |
   o  6:9c48361117de D
   |
   o  2:261e70097290 B2
   |
   o  0:4a2df7238c3b A
   
 
   $ hg up 9
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo "john" > doe
   $ hg add doe
   $ hg commit -m "john doe"
   created new head
   $ hg up 10
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo "foo" > bar
   $ hg add bar
   $ hg commit --amend -m "10'"
   $ hg up 10 --hidden
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo "bar" > foo
   $ hg add foo
   $ hg commit -m "bar foo"
   $ hg log -G
   @  15:73568ab6879d bar foo
   |
   | o  14:77d874d096a2 10'
   | |
   | | o  12:3eb461388009 john doe
   | |/
   x |  10:121d9e3bc4c6 P
   |/
   o  9:4be60e099a77 C
   |
   o  6:9c48361117de D
   |
   o  2:261e70097290 B2
   |
   o  0:4a2df7238c3b A
   
   $ hg summary
   parent: 15:73568ab6879d tip (orphan)
    bar foo
   branch: default
   commit: (clean)
   update: 2 new changesets, 3 branch heads (merge)
   phases: 8 draft
   orphan: 1 changesets
   $ hg rebase -s 10 -d 12
   abort: this rebase will cause divergences from: 121d9e3bc4c6
   (to force the rebase please set experimental.allowdivergence=True)
   [255]
   $ hg log -G
   @  15:73568ab6879d bar foo
   |
   | o  14:77d874d096a2 10'
   | |
   | | o  12:3eb461388009 john doe
   | |/
   x |  10:121d9e3bc4c6 P
   |/
   o  9:4be60e099a77 C
   |
   o  6:9c48361117de D
   |
   o  2:261e70097290 B2
   |
   o  0:4a2df7238c3b A
   
 With experimental.allowdivergence=True, rebase can create divergence
 
   $ hg rebase -s 10 -d 12 --config experimental.allowdivergence=True
   rebasing 10:121d9e3bc4c6 "P"
   rebasing 15:73568ab6879d "bar foo" (tip)
   $ hg summary
   parent: 17:61bd55f69bc4 tip
    bar foo
   branch: default
   commit: (clean)
   update: 1 new changesets, 2 branch heads (merge)
   phases: 8 draft
   content-divergent: 2 changesets
 
 rebase --continue + skipped rev because their successors are in destination
 we make a change in trunk and work on conflicting changes to make rebase abort.
 
   $ hg log -G -r 17::
   @  17:61bd55f69bc4 bar foo
   |
   ~
 
 Create the two changes in trunk
   $ printf "a" > willconflict
   $ hg add willconflict
   $ hg commit -m "willconflict first version"
 
   $ printf "dummy" > C
   $ hg commit -m "dummy change successor"
 
 Create the changes that we will rebase
   $ hg update -C 17 -q
   $ printf "b" > willconflict
   $ hg add willconflict
   $ hg commit -m "willconflict second version"
   created new head
   $ printf "dummy" > K
   $ hg add K
   $ hg commit -m "dummy change"
   $ printf "dummy" > L
   $ hg add L
   $ hg commit -m "dummy change"
   $ hg debugobsolete `hg log -r ".^" -T '{node}'` `hg log -r 19 -T '{node}'` --config experimental.stabilization=all
   obsoleted 1 changesets
 
   $ hg log -G -r 17::
   @  22:7bdc8a87673d dummy change
   |
   x  21:8b31da3c4919 dummy change
   |
   o  20:b82fb57ea638 willconflict second version
   |
   | o  19:601db7a18f51 dummy change successor
   | |
   | o  18:357ddf1602d5 willconflict first version
   |/
   o  17:61bd55f69bc4 bar foo
   |
   ~
   $ hg rebase -r ".^^ + .^ + ." -d 19
   rebasing 20:b82fb57ea638 "willconflict second version"
   merging willconflict
   warning: conflicts while merging willconflict! (edit, then use 'hg resolve --mark')
   unresolved conflicts (see hg resolve, then hg rebase --continue)
   [1]
 
   $ hg resolve --mark willconflict
   (no more unresolved files)
   continue: hg rebase --continue
   $ hg rebase --continue
   rebasing 20:b82fb57ea638 "willconflict second version"
   note: not rebasing 21:8b31da3c4919 "dummy change", already in destination as 19:601db7a18f51 "dummy change successor"
   rebasing 22:7bdc8a87673d "dummy change" (tip)
   $ cd ..
 
 Rebase merge where successor of one parent is equal to destination (issue5198)
 
   $ hg init p1-succ-is-dest
   $ cd p1-succ-is-dest
 
   $ hg debugdrawdag <<EOF
   >   F
   >  /|
   > E D B # replace: D -> B
   >  \|/
   >   A
   > EOF
 
   $ hg rebase -d B -s D
   note: not rebasing 2:b18e25de2cf5 "D" (D), already in destination as 1:112478962961 "B"
   rebasing 4:66f1a38021c9 "F" (F tip)
   $ hg log -G
   o    5:50e9d60b99c6 F
   |\
   | | x  4:66f1a38021c9 F
   | |/|
   | o |  3:7fb047a69f22 E
   | | |
   | | x  2:b18e25de2cf5 D
   | |/
   o |  1:112478962961 B
   |/
   o  0:426bada5c675 A
   
   $ cd ..
 
 Rebase merge where successor of other parent is equal to destination
 
   $ hg init p2-succ-is-dest
   $ cd p2-succ-is-dest
 
   $ hg debugdrawdag <<EOF
   >   F
   >  /|
   > E D B # replace: E -> B
   >  \|/
   >   A
   > EOF
 
-BROKEN: Raises an exception
-  $ hg rebase -d B -s E 2>&1 | grep AssertionError:
-  AssertionError: no base found to rebase on (defineparents called wrong)
+  $ hg rebase -d B -s E
+  note: not rebasing 3:7fb047a69f22 "E" (E), already in destination as 1:112478962961 "B"
+  rebasing 4:66f1a38021c9 "F" (F tip)
   $ hg log -G
-  o    4:66f1a38021c9 F
+  o    5:aae1787dacee F
   |\
-  | x  3:7fb047a69f22 E
-  | |
-  o |  2:b18e25de2cf5 D
-  |/
-  | o  1:112478962961 B
+  | | x  4:66f1a38021c9 F
+  | |/|
+  | | x  3:7fb047a69f22 E
+  | | |
+  | o |  2:b18e25de2cf5 D
+  | |/
+  o /  1:112478962961 B
   |/
   o  0:426bada5c675 A
   
   $ cd ..
 
 Rebase merge where successor of one parent is ancestor of destination
 
   $ hg init p1-succ-in-dest
   $ cd p1-succ-in-dest
 
   $ hg debugdrawdag <<EOF
   >   F C
   >  /| |
   > E D B # replace: D -> B
   >  \|/
   >   A
   > EOF
 
   $ hg rebase -d C -s D
   note: not rebasing 2:b18e25de2cf5 "D" (D), already in destination as 1:112478962961 "B"
   rebasing 5:66f1a38021c9 "F" (F tip)
-BROKEN: not rebased on top of requested destination (C)
+
   $ hg log -G
-  o    6:50e9d60b99c6 F
+  o    6:0913febf6439 F
   |\
-  | | x  5:66f1a38021c9 F
-  | |/|
-  +-----o  4:26805aba1e60 C
+  +---x  5:66f1a38021c9 F
+  | | |
+  | o |  4:26805aba1e60 C
   | | |
-  | o |  3:7fb047a69f22 E
+  o | |  3:7fb047a69f22 E
   | | |
-  | | x  2:b18e25de2cf5 D
-  | |/
-  o |  1:112478962961 B
+  +---x  2:b18e25de2cf5 D
+  | |
+  | o  1:112478962961 B
   |/
   o  0:426bada5c675 A
   
   $ cd ..
 
 Rebase merge where successor of other parent is ancestor of destination
 
   $ hg init p2-succ-in-dest
   $ cd p2-succ-in-dest
 
   $ hg debugdrawdag <<EOF
   >   F C
   >  /| |
   > E D B # replace: E -> B
   >  \|/
   >   A
   > EOF
 
-BROKEN: Raises an exception
-  $ hg rebase -d C -s E 2>&1 | grep AssertionError:
-  AssertionError: no base found to rebase on (defineparents called wrong)
+  $ hg rebase -d C -s E
+  note: not rebasing 3:7fb047a69f22 "E" (E), already in destination as 1:112478962961 "B"
+  rebasing 5:66f1a38021c9 "F" (F tip)
   $ hg log -G
-  o    5:66f1a38021c9 F
+  o    6:c6ab0cc6d220 F
   |\
-  | | o  4:26805aba1e60 C
+  +---x  5:66f1a38021c9 F
   | | |
-  | x |  3:7fb047a69f22 E
+  | o |  4:26805aba1e60 C
   | | |
-  o | |  2:b18e25de2cf5 D
-  |/ /
-  | o  1:112478962961 B
+  | | x  3:7fb047a69f22 E
+  | | |
+  o---+  2:b18e25de2cf5 D
+   / /
+  o /  1:112478962961 B
   |/
   o  0:426bada5c675 A
   
   $ cd ..
 
 Rebase merge where successor of one parent is ancestor of destination
 
   $ hg init p1-succ-in-dest-b
   $ cd p1-succ-in-dest-b
 
   $ hg debugdrawdag <<EOF
   >   F C
   >  /| |
   > E D B # replace: E -> B
   >  \|/
   >   A
   > EOF
 
   $ hg rebase -d C -b F
   rebasing 2:b18e25de2cf5 "D" (D)
   note: not rebasing 3:7fb047a69f22 "E" (E), already in destination as 1:112478962961 "B"
   rebasing 5:66f1a38021c9 "F" (F tip)
+  warning: rebasing 5:66f1a38021c9 may include unwanted changes from 3:7fb047a69f22
   $ hg log -G
   o  7:9ed45af61fa0 F
   |
   o  6:8f47515dda15 D
   |
   | x    5:66f1a38021c9 F
   | |\
   o | |  4:26805aba1e60 C
   | | |
   | | x  3:7fb047a69f22 E
   | | |
   | x |  2:b18e25de2cf5 D
   | |/
   o /  1:112478962961 B
   |/
   o  0:426bada5c675 A
   
   $ cd ..
 
 Rebase merge where successor of other parent is ancestor of destination
 
   $ hg init p2-succ-in-dest-b
   $ cd p2-succ-in-dest-b
 
   $ hg debugdrawdag <<EOF
   >   F C
   >  /| |
   > E D B # replace: D -> B
   >  \|/
   >   A
   > EOF
 
   $ hg rebase -d C -b F
   note: not rebasing 2:b18e25de2cf5 "D" (D), already in destination as 1:112478962961 "B"
   rebasing 3:7fb047a69f22 "E" (E)
   rebasing 5:66f1a38021c9 "F" (F tip)
-BROKEN: This should have resulted in a rebased F with one parent, just like in
-the test case above
+  warning: rebasing 5:66f1a38021c9 may include unwanted changes from 2:b18e25de2cf5
+
   $ hg log -G
-  o    7:c1e6f26e339d F
-  |\
-  | o  6:533690786a86 E
-  |/
+  o  7:502540f44880 F
+  |
+  o  6:533690786a86 E
+  |
   | x    5:66f1a38021c9 F
   | |\
   o | |  4:26805aba1e60 C
   | | |
   | | x  3:7fb047a69f22 E
   | | |
   | x |  2:b18e25de2cf5 D
   | |/
   o /  1:112478962961 B
   |/
   o  0:426bada5c675 A
   
   $ cd ..
 
 Test that bookmark is moved and working dir is updated when all changesets have
 equivalents in destination
   $ hg init rbsrepo && cd rbsrepo
   $ echo "[experimental]" > .hg/hgrc
   $ echo "stabilization=all" >> .hg/hgrc
   $ echo "rebaseskipobsolete=on" >> .hg/hgrc
   $ echo root > root && hg ci -Am root
   adding root
   $ echo a > a && hg ci -Am a
   adding a
   $ hg up 0
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo b > b && hg ci -Am b
   adding b
   created new head
   $ hg rebase -r 2 -d 1
   rebasing 2:1e9a3c00cbe9 "b" (tip)
   $ hg log -r .  # working dir is at rev 3 (successor of 2)
   3:be1832deae9a b (no-eol)
   $ hg book -r 2 mybook --hidden  # rev 2 has a bookmark on it now
   $ hg up 2 && hg log -r .  # working dir is at rev 2 again
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   2:1e9a3c00cbe9 b (no-eol)
   $ hg rebase -r 2 -d 3 --config experimental.stabilization.track-operation=1
   note: not rebasing 2:1e9a3c00cbe9 "b" (mybook), already in destination as 3:be1832deae9a "b"
 Check that working directory was updated to rev 3 although rev 2 was skipped
 during the rebase operation
   $ hg log -r .
   3:be1832deae9a b (no-eol)
 
 Check that bookmark was not moved to rev 3 if rev 2 was skipped during the
 rebase operation. This makes sense because if rev 2 has a successor, the
 operation generating that successor (ex. rebase) should be responsible for
 moving bookmarks. If the bookmark is on a precursor, like rev 2, that means the
 user manually moved it back. In that case we should not move it again.
   $ hg bookmarks
      mybook                    2:1e9a3c00cbe9
   $ hg debugobsolete --rev tip
   1e9a3c00cbe90d236ac05ef61efcc5e40b7412bc be1832deae9ac531caa7438b8dcf6055a122cd8e 0 (*) {'user': 'test'} (glob)