# 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)