rebase: return early when source is descendant of destination

This only happens when using --base (or no source selection options), as
rebase already aborts in this situation when using --source.

Without this change you get an abort from the underlying merge, and the
repository is in a different state than you started with (the working
dir parent is changed).

hgext/rebase.py

@@ -1,471 +1,475 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, incorporated herein by reference.
 
 '''command to move sets of revisions to a different ancestor
 
 This extension lets you rebase changesets in an existing Mercurial
 repository.
 
 For more information:
 http://mercurial.selenic.com/wiki/RebaseExtension
 '''
 
 from mercurial import util, repair, merge, cmdutil, commands, error
 from mercurial import extensions, ancestor, copies, patch
 from mercurial.commands import templateopts
 from mercurial.node import nullrev
 from mercurial.lock import release
 from mercurial.i18n import _
 import os, errno
 
 def rebasemerge(repo, rev, first=False):
     'return the correct ancestor'
     oldancestor = ancestor.ancestor
 
     def newancestor(a, b, pfunc):
         ancestor.ancestor = oldancestor
         if b == rev:
             return repo[rev].parents()[0].rev()
         return ancestor.ancestor(a, b, pfunc)
 
     if not first:
         ancestor.ancestor = newancestor
     else:
         repo.ui.debug("first revision, do not change ancestor\n")
     stats = merge.update(repo, rev, True, True, False)
     return stats
 
 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 onto another. This can be useful for linearizing local
     changes relative to a master development tree.
 
     If a rebase is interrupted to manually resolve a merge, it can be
     continued with --continue/-c or aborted with --abort/-a.
     """
     originalwd = target = None
     external = nullrev
     state = {}
     skipped = set()
 
     lock = wlock = None
     try:
         lock = repo.lock()
         wlock = repo.wlock()
 
         # Validate input and define rebasing points
         destf = opts.get('dest', None)
         srcf = opts.get('source', None)
         basef = opts.get('base', None)
         contf = opts.get('continue')
         abortf = opts.get('abort')
         collapsef = opts.get('collapse', False)
         extrafn = opts.get('extrafn')
         keepf = opts.get('keep', False)
         keepbranchesf = opts.get('keepbranches', False)
 
         if contf or abortf:
             if contf and abortf:
                 raise error.ParseError('rebase',
                                        _('cannot use both abort and continue'))
             if collapsef:
                 raise error.ParseError(
                     'rebase', _('cannot use collapse with continue or abort'))
 
             if srcf or basef or destf:
                 raise error.ParseError('rebase',
                     _('abort and continue do not allow specifying revisions'))
 
             (originalwd, target, state, collapsef, keepf,
                                 keepbranchesf, external) = restorestatus(repo)
             if abortf:
                 abort(repo, originalwd, target, state)
                 return
         else:
             if srcf and basef:
                 raise error.ParseError('rebase', _('cannot specify both a '
                                                    'revision and a base'))
             cmdutil.bail_if_changed(repo)
             result = buildstate(repo, destf, srcf, basef, collapsef)
             if result:
                 originalwd, target, state, external = result
             else: # Empty state built, nothing to rebase
                 ui.status(_('nothing to rebase\n'))
                 return
 
         if keepbranchesf:
             if extrafn:
                 raise error.ParseError(
                     'rebase', _('cannot use both keepbranches and extrafn'))
             def extrafn(ctx, extra):
                 extra['branch'] = ctx.branch()
 
         # Rebase
         targetancestors = list(repo.changelog.ancestors(target))
         targetancestors.append(target)
 
         for rev in sorted(state):
             if state[rev] == -1:
                 storestatus(repo, originalwd, target, state, collapsef, keepf,
                                                     keepbranchesf, external)
                 rebasenode(repo, rev, target, state, skipped, targetancestors,
                                                        collapsef, extrafn)
         ui.note(_('rebase merging completed\n'))
 
         if collapsef:
             p1, p2 = defineparents(repo, min(state), target,
                                                         state, targetancestors)
             concludenode(repo, rev, p1, external, state, collapsef,
                          last=True, skipped=skipped, extrafn=extrafn)
 
         if 'qtip' in repo.tags():
             updatemq(repo, state, skipped, **opts)
 
         if not keepf:
             # Remove no more useful revisions
             if set(repo.changelog.descendants(min(state))) - set(state):
                 ui.warn(_("warning: new changesets detected on source branch, "
                                                         "not stripping\n"))
             else:
                 repair.strip(ui, repo, repo[min(state)].node(), "strip")
 
         clearstatus(repo)
         ui.status(_("rebase completed\n"))
         if os.path.exists(repo.sjoin('undo')):
             util.unlink(repo.sjoin('undo'))
         if skipped:
             ui.note(_("%d revisions have been skipped\n") % len(skipped))
     finally:
         release(lock, wlock)
 
 def concludenode(repo, rev, p1, p2, state, collapse, last=False, skipped=None,
                  extrafn=None):
     """Skip commit if collapsing has been required and rev is not the last
     revision, commit otherwise
     """
     repo.ui.debug(" set parents\n")
     if collapse and not last:
         repo.dirstate.setparents(repo[p1].node())
         return None
 
     repo.dirstate.setparents(repo[p1].node(), repo[p2].node())
 
     if skipped is None:
         skipped = set()
 
     # Commit, record the old nodeid
     newrev = nullrev
     try:
         if last:
             # we don't translate commit messages
             commitmsg = 'Collapsed revision'
             for rebased in state:
                 if rebased not in skipped:
                     commitmsg += '\n* %s' % repo[rebased].description()
             commitmsg = repo.ui.edit(commitmsg, repo.ui.username())
         else:
             commitmsg = repo[rev].description()
         # Commit might fail if unresolved files exist
         extra = {'rebase_source': repo[rev].hex()}
         if extrafn:
             extrafn(repo[rev], extra)
         newrev = repo.commit(text=commitmsg, user=repo[rev].user(),
                              date=repo[rev].date(), extra=extra)
         repo.dirstate.setbranch(repo[newrev].branch())
         return newrev
     except util.Abort:
         # Invalidate the previous setparents
         repo.dirstate.invalidate()
         raise
 
 def rebasenode(repo, rev, target, state, skipped, targetancestors, collapse,
                extrafn):
     'Rebase a single revision'
     repo.ui.debug("rebasing %d:%s\n" % (rev, repo[rev]))
 
     p1, p2 = defineparents(repo, rev, target, state, targetancestors)
 
     repo.ui.debug(" future parents are %d and %d\n" % (repo[p1].rev(),
                                                             repo[p2].rev()))
 
     # Merge phase
     if len(repo.parents()) != 2:
         # Update to target and merge it with local
         if repo['.'].rev() != repo[p1].rev():
             repo.ui.debug(" update to %d:%s\n" % (repo[p1].rev(), repo[p1]))
             merge.update(repo, p1, False, True, False)
         else:
             repo.ui.debug(" already in target\n")
         repo.dirstate.write()
         repo.ui.debug(" merge against %d:%s\n" % (repo[rev].rev(), repo[rev]))
         first = repo[rev].rev() == repo[min(state)].rev()
         stats = rebasemerge(repo, rev, first)
 
         if stats[3] > 0:
             raise util.Abort(_('fix unresolved conflicts with hg resolve then '
                                                 'run hg rebase --continue'))
     else: # we have an interrupted rebase
         repo.ui.debug('resuming interrupted rebase\n')
 
     # Keep track of renamed files in the revision that is going to be rebased
     # Here we simulate the copies and renames in the source changeset
     cop, diver = copies.copies(repo, repo[rev], repo[target], repo[p2], True)
     m1 = repo[rev].manifest()
     m2 = repo[target].manifest()
     for k, v in cop.iteritems():
         if k in m1:
             if v in m1 or v in m2:
                 repo.dirstate.copy(v, k)
                 if v in m2 and v not in m1:
                     repo.dirstate.remove(v)
 
     newrev = concludenode(repo, rev, p1, p2, state, collapse,
                           extrafn=extrafn)
 
     # Update the state
     if newrev is not None:
         state[rev] = repo[newrev].rev()
     else:
         if not collapse:
             repo.ui.note(_('no changes, revision %d skipped\n') % rev)
             repo.ui.debug('next revision set to %s\n' % p1)
             skipped.add(rev)
         state[rev] = p1
 
 def defineparents(repo, rev, target, state, targetancestors):
     'Return the new parent relationship of the revision that will be rebased'
     parents = repo[rev].parents()
     p1 = p2 = nullrev
 
     P1n = parents[0].rev()
     if P1n in targetancestors:
         p1 = target
     elif P1n in state:
         p1 = state[P1n]
     else: # P1n external
         p1 = target
         p2 = P1n
 
     if len(parents) == 2 and parents[1].rev() not in targetancestors:
         P2n = parents[1].rev()
         # interesting second parent
         if P2n in state:
             if p1 == target: # P1n in targetancestors or external
                 p1 = state[P2n]
             else:
                 p2 = state[P2n]
         else: # P2n external
             if p2 != nullrev: # P1n external too => rev is a merged revision
                 raise util.Abort(_('cannot use revision %d as base, result '
                         'would have 3 parents') % rev)
             p2 = P2n
     return p1, p2
 
 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 = {}
     for p in repo.mq.applied:
         if repo[p.rev].rev() in state:
             repo.ui.debug('revision %d is an mq patch (%s), finalize it.\n' %
                                         (repo[p.rev].rev(), p.name))
             mqrebase[repo[p.rev].rev()] = (p.name, isagitpatch(repo, p.name))
 
     if mqrebase:
         repo.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:
                 repo.ui.debug('import mq patch %d (%s)\n'
                               % (state[rev], mqrebase[rev][0]))
                 repo.mq.qimport(repo, (), patchname=mqrebase[rev][0],
                             git=mqrebase[rev][1],rev=[str(state[rev])])
         repo.mq.save_dirty()
 
 def storestatus(repo, originalwd, target, state, collapse, keep, keepbranches,
                                                                 external):
     'Store the current status to allow recovery'
     f = repo.opener("rebasestate", "w")
     f.write(repo[originalwd].hex() + '\n')
     f.write(repo[target].hex() + '\n')
     f.write(repo[external].hex() + '\n')
     f.write('%d\n' % int(collapse))
     f.write('%d\n' % int(keep))
     f.write('%d\n' % int(keepbranches))
     for d, v in state.iteritems():
         oldrev = repo[d].hex()
         newrev = repo[v].hex()
         f.write("%s:%s\n" % (oldrev, newrev))
     f.close()
     repo.ui.debug('rebase status stored\n')
 
 def clearstatus(repo):
     'Remove the status files'
     if os.path.exists(repo.join("rebasestate")):
         util.unlink(repo.join("rebasestate"))
 
 def restorestatus(repo):
     'Restore a previously stored status'
     try:
         target = None
         collapse = False
         external = nullrev
         state = {}
         f = repo.opener("rebasestate")
         for i, l in enumerate(f.read().splitlines()):
             if i == 0:
                 originalwd = repo[l].rev()
             elif i == 1:
                 target = 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))
             else:
                 oldrev, newrev = l.split(':')
                 state[repo[oldrev].rev()] = repo[newrev].rev()
         repo.ui.debug('rebase status resumed\n')
         return originalwd, target, state, collapse, keep, keepbranches, external
     except IOError, err:
         if err.errno != errno.ENOENT:
             raise
         raise util.Abort(_('no rebase in progress'))
 
 def abort(repo, originalwd, target, state):
     'Restore the repository to its original state'
     if set(repo.changelog.descendants(target)) - set(state.values()):
         repo.ui.warn(_("warning: new changesets detected on target branch, "
                                                     "not stripping\n"))
     else:
         # Strip from the first rebased revision
         merge.update(repo, repo[originalwd].rev(), False, True, False)
         rebased = filter(lambda x: x > -1, state.values())
         if rebased:
             strippoint = min(rebased)
             repair.strip(repo.ui, repo, repo[strippoint].node(), "strip")
         clearstatus(repo)
         repo.ui.status(_('rebase aborted\n'))
 
 def buildstate(repo, dest, src, base, collapse):
     'Define which revisions are going to be rebased and where'
     targetancestors = set()
 
     if not dest:
         # Destination defaults to the latest revision in the current branch
         branch = repo[None].branch()
         dest = repo[branch].rev()
     else:
         if 'qtip' in repo.tags() and (repo[dest].hex() in
                                 [s.rev for s in repo.mq.applied]):
             raise util.Abort(_('cannot rebase onto an applied mq patch'))
         dest = repo[dest].rev()
 
     if src:
         commonbase = repo[src].ancestor(repo[dest])
         if commonbase == repo[src]:
             raise util.Abort(_('source is ancestor of destination'))
         if commonbase == repo[dest]:
             raise util.Abort(_('source is descendant of destination'))
         source = repo[src].rev()
     else:
         if base:
             cwd = repo[base].rev()
         else:
             cwd = repo['.'].rev()
 
         if cwd == dest:
             repo.ui.debug('source and destination are the same\n')
             return None
 
         targetancestors = set(repo.changelog.ancestors(dest))
         if cwd in targetancestors:
             repo.ui.debug('source is ancestor of destination\n')
             return None
 
         cwdancestors = set(repo.changelog.ancestors(cwd))
+        if dest in cwdancestors:
+            repo.ui.debug('source is descendant of destination\n')
+            return None
+
         cwdancestors.add(cwd)
         rebasingbranch = cwdancestors - targetancestors
         source = min(rebasingbranch)
 
     repo.ui.debug('rebase onto %d starting from %d\n' % (dest, source))
     state = dict.fromkeys(repo.changelog.descendants(source), nullrev)
     external = nullrev
     if collapse:
         if not targetancestors:
             targetancestors = set(repo.changelog.ancestors(dest))
         for rev in state:
             # Check externals and fail if there are more than one
             for p in repo[rev].parents():
                 if (p.rev() not in state and p.rev() != source
                             and p.rev() not in targetancestors):
                     if external != nullrev:
                         raise util.Abort(_('unable to collapse, there is more '
                                 'than one external parent'))
                     external = p.rev()
 
     state[source] = nullrev
     return repo['.'].rev(), repo[dest].rev(), state, external
 
 def pullrebase(orig, ui, repo, *args, **opts):
     'Call rebase after pull if the latter has been invoked with --rebase'
     if opts.get('rebase'):
         if opts.get('update'):
             del opts['update']
             ui.debug('--update and --rebase are not compatible, ignoring '
                      'the update flag\n')
 
         cmdutil.bail_if_changed(repo)
         revsprepull = len(repo)
         orig(ui, repo, *args, **opts)
         revspostpull = len(repo)
         if revspostpull > revsprepull:
             rebase(ui, repo, **opts)
             branch = repo[None].branch()
             dest = repo[branch].rev()
             if dest != repo['.'].rev():
                 # there was nothing to rebase we force an update
                 merge.update(repo, dest, False, False, False)
     else:
         orig(ui, repo, *args, **opts)
 
 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"))
 )
 
 cmdtable = {
 "rebase":
         (rebase,
         [
         ('s', 'source', '', _('rebase from a given revision')),
         ('b', 'base', '', _('rebase from the base of a given revision')),
         ('d', 'dest', '', _('rebase onto a given revision')),
         ('', 'collapse', False, _('collapse the rebased revisions')),
         ('', 'keep', False, _('keep original revisions')),
         ('', 'keepbranches', False, _('keep original branches')),
         ('c', 'continue', False, _('continue an interrupted rebase')),
         ('a', 'abort', False, _('abort an interrupted rebase')),] +
          templateopts,
         _('hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--keep] '
                             '[--keepbranches] | [-c] | [-a]')),
 }

tests/test-rebase-scenario-global

@@ -1,82 +1,91 b''
 #!/bin/sh
 
 echo "[extensions]" >> $HGRCPATH
 echo "graphlog=" >> $HGRCPATH
 echo "rebase=" >> $HGRCPATH
 
 BASE=`pwd`
 
 addcommit () {
     echo $1 > $1
     hg add $1
     hg commit -d "${2} 0" -m $1
 }
 
 commit () {
     hg commit -d "${2} 0" -m $1
 }
 
 createrepo () {
     cd $BASE
     rm -rf a
     hg init a
     cd a
     addcommit "A" 0
     addcommit "B" 1
 
     hg update -C 0
     addcommit "C" 2
 
     hg update -C 0
     addcommit "D" 3
 
     hg merge -r 2
     commit "E" 4
 
     hg update -C 3
     addcommit "F" 5
 }
 
 createrepo > /dev/null 2>&1
 hg glog  --template '{rev}: {desc}\n'
 
 echo '% Rebasing'
 echo '% B onto F - simple rebase'
 hg rebase -s 1 -d 5 2>&1 | sed 's/\(saving bundle to \).*/\1/'
 hg glog  --template '{rev}: {desc}\n'
 
 createrepo > /dev/null 2>&1
 echo '% B onto D - intermediate point'
 hg rebase -s 1 -d 3 2>&1 | sed 's/\(saving bundle to \).*/\1/'
 hg glog  --template '{rev}: {desc}\n'
 
 createrepo > /dev/null 2>&1
 echo '% C onto F - skip of E'
 hg rebase -s 2 -d 5 2>&1 | sed 's/\(saving bundle to \).*/\1/'
 hg glog  --template '{rev}: {desc}\n'
 
 createrepo > /dev/null 2>&1
 echo '% D onto C - rebase of a branching point (skip E)'
 hg rebase -s 3 -d 2 2>&1 | sed 's/\(saving bundle to \).*/\1/'
 hg glog  --template '{rev}: {desc}\n'
 
 createrepo > /dev/null 2>&1
 echo '% E onto F - merged revision having a parent in ancestors of target'
 hg rebase -s 4 -d 5 2>&1 | sed 's/\(saving bundle to \).*/\1/'
 hg glog  --template '{rev}: {desc}\n'
 
 createrepo > /dev/null 2>&1
 echo '% D onto B - E maintains C as parent'
 hg rebase -s 3 -d 1 2>&1 | sed 's/\(saving bundle to \).*/\1/'
 hg glog  --template '{rev}: {desc}\n'
 
-echo '% These will fail'
+echo '% These will fail (using --source)'
 createrepo > /dev/null 2>&1
 echo '% E onto D - rebase onto an ancestor'
 hg rebase -s 4 -d 3
 echo '% D onto E - rebase onto a descendant'
 hg rebase -s 3 -d 4
 echo '% E onto B - merge revision with both parents not in ancestors of target'
 hg rebase -s 4 -d 1
 
+echo
+echo '% These will abort gracefully (using --base)'
+echo '% E onto E - rebase onto same changeset'
+hg rebase -b 4 -d 4
+echo '% E onto D - rebase onto an ancestor'
+hg rebase -b 4 -d 3
+echo '% D onto E - rebase onto a descendant'
+hg rebase -b 3 -d 4
+
 exit 0

tests/test-rebase-scenario-global.out

@@ -1,136 +1,144 b''
 @  5: F
 |
 | o  4: E
 |/|
 o |  3: D
 | |
 | o  2: C
 |/
 | o  1: B
 |/
 o  0: A
 
 % Rebasing
 % B onto F - simple rebase
 saving bundle to 
 adding branch
 adding changesets
 adding manifests
 adding file changes
 added 5 changesets with 4 changes to 4 files (+1 heads)
 rebase completed
 @  5: B
 |
 o  4: F
 |
 | o  3: E
 |/|
 o |  2: D
 | |
 | o  1: C
 |/
 o  0: A
 
 % B onto D - intermediate point
 saving bundle to 
 adding branch
 adding changesets
 adding manifests
 adding file changes
 added 5 changesets with 4 changes to 4 files (+2 heads)
 rebase completed
 @  5: B
 |
 | o  4: F
 |/
 | o  3: E
 |/|
 o |  2: D
 | |
 | o  1: C
 |/
 o  0: A
 
 % C onto F - skip of E
 saving bundle to 
 adding branch
 adding changesets
 adding manifests
 adding file changes
 added 3 changesets with 3 changes to 3 files (+1 heads)
 rebase completed
 @  4: C
 |
 o  3: F
 |
 o  2: D
 |
 | o  1: B
 |/
 o  0: A
 
 % D onto C - rebase of a branching point (skip E)
 saving bundle to 
 adding branch
 adding changesets
 adding manifests
 adding file changes
 added 2 changesets with 2 changes to 2 files
 rebase completed
 @  4: F
 |
 o  3: D
 |
 o  2: C
 |
 | o  1: B
 |/
 o  0: A
 
 % E onto F - merged revision having a parent in ancestors of target
 saving bundle to 
 adding branch
 adding changesets
 adding manifests
 adding file changes
 added 2 changesets with 1 changes to 1 files (-1 heads)
 rebase completed
 @    5: E
 |\
 | o  4: F
 | |
 | o  3: D
 | |
 o |  2: C
 |/
 | o  1: B
 |/
 o  0: A
 
 % D onto B - E maintains C as parent
 saving bundle to 
 adding branch
 adding changesets
 adding manifests
 adding file changes
 added 3 changesets with 2 changes to 2 files
 rebase completed
 @  5: F
 |
 | o  4: E
 |/|
 o |  3: D
 | |
 | o  2: C
 | |
 o |  1: B
 |/
 o  0: A
 
-% These will fail
+% These will fail (using --source)
 % E onto D - rebase onto an ancestor
 abort: source is descendant of destination
 % D onto E - rebase onto a descendant
 abort: source is ancestor of destination
 % E onto B - merge revision with both parents not in ancestors of target
 abort: cannot use revision 4 as base, result would have 3 parents
+
+% These will abort gracefully (using --base)
+% E onto E - rebase onto same changeset
+nothing to rebase
+% E onto D - rebase onto an ancestor
+nothing to rebase
+% D onto E - rebase onto a descendant
+nothing to rebase