# 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:

http://mercurial.selenic.com/wiki/RebaseExtension

'''

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

nullmerge = -2

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()

    targetancestors = 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)

        detachf = opts.get('detach', 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 detachf:

                raise error.ParseError(

                    'rebase', _('cannot use detach 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'))

            if detachf:

                if not srcf:

                    raise error.ParseError(

                      'rebase', _('detach requires a revision to be specified'))

                if basef:

                    raise error.ParseError(

                        'rebase', _('cannot specify a base with detach'))

            cmdutil.bail_if_changed(repo)

            result = buildstate(repo, destf, srcf, basef, detachf)

            if not result:

                # Empty state built, nothing to rebase

                ui.status(_('nothing to rebase\n'))

                return

            else:

                originalwd, target, state = result

                if collapsef:

                    targetancestors = set(repo.changelog.ancestors(target))

                    external = checkexternal(repo, state, targetancestors)

        if keepbranchesf:

            if extrafn:

                raise error.ParseError(

                    'rebase', _('cannot use both keepbranches and extrafn'))

            def extrafn(ctx, extra):

                extra['branch'] = ctx.branch()

        # Rebase

        if not targetancestors:

            targetancestors = set(repo.changelog.ancestors(target))

            targetancestors.add(target)

        for rev in sorted(state):

            if state[rev] == -1:

                ui.debug("rebasing %d:%s\n" % (rev, repo[rev]))

                storestatus(repo, originalwd, target, state, collapsef, keepf,

                                                    keepbranchesf, external)

                p1, p2 = defineparents(repo, rev, target, state,

                                                        targetancestors)

                if len(repo.parents()) == 2:

                    repo.ui.debug('resuming interrupted rebase\n')

                else:

                    stats = rebasenode(repo, rev, p1, p2, state)

                    if stats and stats[3] > 0:

                        raise util.Abort(_('fix unresolved conflicts with hg '

                                    'resolve then run hg rebase --continue'))

                updatedirstate(repo, rev, target, p2)

                if not collapsef:

                    extra = {'rebase_source': repo[rev].hex()}

                    if extrafn:

                        extrafn(repo[rev], extra)

                    newrev = concludenode(repo, rev, p1, p2, extra=extra)

                else:

                    # Skip commit if we are collapsing

                    repo.dirstate.setparents(repo[p1].node())

                    newrev = None

                # Update the state

                if newrev is not None:

                    state[rev] = repo[newrev].rev()

                else:

                    if not collapsef:

                        ui.note(_('no changes, revision %d skipped\n') % rev)

                        ui.debug('next revision set to %s\n' % p1)

                        skipped.add(rev)

                    state[rev] = p1

        ui.note(_('rebase merging completed\n'))

        if collapsef:

            p1, p2 = defineparents(repo, min(state), target,

                                                        state, targetancestors)

            commitmsg = 'Collapsed revision'

            for rebased in state:

                if rebased not in skipped and state[rebased] != nullmerge:

                    commitmsg += '\n* %s' % repo[rebased].description()

            commitmsg = ui.edit(commitmsg, repo.ui.username())

            newrev = concludenode(repo, rev, p1, external, commitmsg=commitmsg,

                                                    extra=extrafn)

        if 'qtip' in repo.tags():

            updatemq(repo, state, skipped, **opts)

        if not keepf:

            # Remove no more useful revisions

            rebased = [rev for rev in state if state[rev] != nullmerge]

            if rebased:

                if set(repo.changelog.descendants(min(rebased))) - set(state):

                    ui.warn(_("warning: new changesets detected "

                              "on source branch, not stripping\n"))

                else:

                    repair.strip(ui, repo, repo[min(rebased)].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 rebasemerge(repo, rev, first=False):

    'return the correct ancestor'

    oldancestor = ancestor.ancestor

    def newancestor(a, b, pfunc):

        if b == rev:

            return repo[rev].parents()[0].rev()

        return oldancestor(a, b, pfunc)

    if not first:

        ancestor.ancestor = newancestor

    else:

        repo.ui.debug("first revision, do not change ancestor\n")

    try:

        stats = merge.update(repo, rev, True, True, False)

        return stats

    finally:

        ancestor.ancestor = oldancestor

def checkexternal(repo, state, targetancestors):

    """Check whether one or more external revisions need to be taken in

    consideration. In the latter case, abort.

    """

    external = nullrev

    source = min(state)

    for rev in state:

        if rev == source:

            continue

        # 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() not in targetancestors):

                if external != nullrev:

                    raise util.Abort(_('unable to collapse, there is more '

                            'than one external parent'))

                external = p.rev()

    return external

def updatedirstate(repo, rev, p1, p2):

    """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[p1], repo[p2], True)

    m1 = repo[rev].manifest()

    m2 = repo[p1].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)

def concludenode(repo, rev, p1, p2, commitmsg=None, extra=None):

    'Commit the changes and store useful information in extra'

    try:

        repo.dirstate.setparents(repo[p1].node(), repo[p2].node())

        if commitmsg is None:

            commitmsg = repo[rev].description()

        if extra is None:

            extra = {}

        # Commit might fail if unresolved files exist

        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, p1, p2, state):

    'Rebase a single revision'

    # Merge phase

    # 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)

    return stats

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:

        if state[P1n] == nullmerge:

            p1 = target

        else:

            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

    repo.ui.debug(" future parents are %d and %d\n" %

                            (repo[p1].rev(), repo[p2].rev()))

    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