hgext/histedit.py

histedit: new extension for interactive history editing

# histedit.py - interactive history editing for mercurial
#
# Copyright 2009 Augie Fackler <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""Interactive history editing.

Inspired by git rebase --interactive.
"""
from inspect import getargspec
try:
    import cPickle as pickle
except ImportError:
    import pickle
import tempfile
import os

from mercurial import bookmarks
from mercurial import cmdutil
from mercurial import discovery
from mercurial import error
from mercurial import hg
from mercurial import node
from mercurial import patch
from mercurial import repair
from mercurial import scmutil
from mercurial import url
from mercurial import util
from mercurial.i18n import _


editcomment = """

# Edit history between %s and %s
#
# Commands:
#  p, pick = use commit
#  e, edit = use commit, but stop for amending
#  f, fold = use commit, but fold into previous commit (combines N and N-1)
#  d, drop = remove commit from history
#  m, mess = edit message without changing commit content
#
"""

def between(repo, old, new, keep):
    revs = [old, ]
    current = old
    while current != new:
        ctx = repo[current]
        if not keep and len(ctx.children()) > 1:
            raise util.Abort(_('cannot edit history that would orphan nodes'))
        if len(ctx.parents()) != 1 and ctx.parents()[1] != node.nullid:
            raise util.Abort(_("can't edit history with merges"))
        if not ctx.children():
            current = new
        else:
            current = ctx.children()[0].node()
            revs.append(current)
    if len(repo[current].children()) and not keep:
        raise util.Abort(_('cannot edit history that would orphan nodes'))
    return revs


def pick(ui, repo, ctx, ha, opts):
    oldctx = repo[ha]
    if oldctx.parents()[0] == ctx:
        ui.debug('node %s unchanged\n' % ha)
        return oldctx, [], [], []
    hg.update(repo, ctx.node())
    fd, patchfile = tempfile.mkstemp(prefix='hg-histedit-')
    fp = os.fdopen(fd, 'w')
    diffopts = patch.diffopts(ui, opts)
    diffopts.git = True
    diffopts.ignorews = False
    diffopts.ignorewsamount = False
    diffopts.ignoreblanklines = False
    gen = patch.diff(repo, oldctx.parents()[0].node(), ha, opts=diffopts)
    for chunk in gen:
        fp.write(chunk)
    fp.close()
    try:
        files = set()
        try:
            patch.patch(ui, repo, patchfile, files=files, eolmode=None)
            if not files:
                ui.warn(_('%s: empty changeset')
                             % node.hex(ha))
                return ctx, [], [], []
        finally:
            os.unlink(patchfile)
    except Exception, inst:
        raise util.Abort(_('Fix up the change and run '
                           'hg histedit --continue'))
    n = repo.commit(text=oldctx.description(), user=oldctx.user(), date=oldctx.date(),
                    extra=oldctx.extra())
    return repo[n], [n, ], [oldctx.node(), ], []


def edit(ui, repo, ctx, ha, opts):
    oldctx = repo[ha]
    hg.update(repo, ctx.node())
    fd, patchfile = tempfile.mkstemp(prefix='hg-histedit-')
    fp = os.fdopen(fd, 'w')
    diffopts = patch.diffopts(ui, opts)
    diffopts.git = True
    diffopts.ignorews = False
    diffopts.ignorewsamount = False
    diffopts.ignoreblanklines = False
    gen = patch.diff(repo, oldctx.parents()[0].node(), ha, opts=diffopts)
    for chunk in gen:
        fp.write(chunk)
    fp.close()
    try:
        files = set()
        try:
            patch.patch(ui, repo, patchfile, files=files, eolmode=None)
        finally:
            os.unlink(patchfile)
    except Exception, inst:
        pass
    raise util.Abort(_('Make changes as needed, you may commit or record as '
                       'needed now.\nWhen you are finished, run hg'
                       ' histedit --continue to resume.'))

def fold(ui, repo, ctx, ha, opts):
    oldctx = repo[ha]
    hg.update(repo, ctx.node())
    fd, patchfile = tempfile.mkstemp(prefix='hg-histedit-')
    fp = os.fdopen(fd, 'w')
    diffopts = patch.diffopts(ui, opts)
    diffopts.git = True
    diffopts.ignorews = False
    diffopts.ignorewsamount = False
    diffopts.ignoreblanklines = False
    gen = patch.diff(repo, oldctx.parents()[0].node(), ha, opts=diffopts)
    for chunk in gen:
        fp.write(chunk)
    fp.close()
    try:
        files = set()
        try:
            patch.patch(ui, repo, patchfile, files=files, eolmode=None)
            if not files:
                ui.warn(_('%s: empty changeset')
                             % node.hex(ha))
                return ctx, [], [], []
        finally:
            os.unlink(patchfile)
    except Exception, inst:
        raise util.Abort(_('Fix up the change and run '
                           'hg histedit --continue'))
    n = repo.commit(text='fold-temp-revision %s' % ha, user=oldctx.user(), date=oldctx.date(),
                    extra=oldctx.extra())
    return finishfold(ui, repo, ctx, oldctx, n, opts, [])

def finishfold(ui, repo, ctx, oldctx, newnode, opts, internalchanges):
    parent = ctx.parents()[0].node()
    hg.update(repo, parent)
    fd, patchfile = tempfile.mkstemp(prefix='hg-histedit-')
    fp = os.fdopen(fd, 'w')
    diffopts = patch.diffopts(ui, opts)
    diffopts.git = True
    diffopts.ignorews = False
    diffopts.ignorewsamount = False
    diffopts.ignoreblanklines = False
    gen = patch.diff(repo, parent, newnode, opts=diffopts)
    for chunk in gen:
        fp.write(chunk)
    fp.close()
    files = set()
    try:
        patch.patch(ui, repo, patchfile, files=files, eolmode=None)
    finally:
        os.unlink(patchfile)
    newmessage = '\n***\n'.join(
        [ctx.description(), ] +
        [repo[r].description() for r in internalchanges] +
        [oldctx.description(), ])
    # If the changesets are from the same author, keep it.
    if ctx.user() == oldctx.user():
        username = ctx.user()
    else:
        username = ui.username()
    newmessage = ui.edit(newmessage, username)
    n = repo.commit(text=newmessage, user=username, date=max(ctx.date(), oldctx.date()),
                    extra=oldctx.extra())
    return repo[n], [n, ], [oldctx.node(), ctx.node() ], [newnode, ]

def drop(ui, repo, ctx, ha, opts):
    return ctx, [], [repo[ha].node(), ], []


def message(ui, repo, ctx, ha, opts):
    oldctx = repo[ha]
    hg.update(repo, ctx.node())
    fd, patchfile = tempfile.mkstemp(prefix='hg-histedit-')
    fp = os.fdopen(fd, 'w')
    diffopts = patch.diffopts(ui, opts)
    diffopts.git = True
    diffopts.ignorews = False
    diffopts.ignorewsamount = False
    diffopts.ignoreblanklines = False
    gen = patch.diff(repo, oldctx.parents()[0].node(), ha, opts=diffopts)
    for chunk in gen:
        fp.write(chunk)
    fp.close()
    try:
        files = set()
        try:
            patch.patch(ui, repo, patchfile, files=files, eolmode=None)
        finally:
            os.unlink(patchfile)
    except Exception, inst:
        raise util.Abort(_('Fix up the change and run '
                           'hg histedit --continue'))
    message = oldctx.description()
    message = ui.edit(message, ui.username())
    new = repo.commit(text=message, user=oldctx.user(), date=oldctx.date(),
                      extra=oldctx.extra())
    newctx = repo[new]
    if oldctx.node() != newctx.node():
        return newctx, [new], [oldctx.node()], []
    # We didn't make an edit, so just indicate no replaced nodes
    return newctx, [new], [], []


def makedesc(c):
    summary = ''
    if c.description():
        summary = c.description().splitlines()[0]
    line = 'pick %s %d %s' % (c.hex()[:12], c.rev(), summary)
    return line[:80]  # trim to 80 chars so it's not stupidly wide in my editor

actiontable = {'p': pick,
               'pick': pick,
               'e': edit,
               'edit': edit,
               'f': fold,
               'fold': fold,
               'd': drop,
               'drop': drop,
               'm': message,
               'mess': message,
               }
def histedit(ui, repo, *parent, **opts):
    """hg histedit <parent>
    """
    # TODO only abort if we try and histedit mq patches, not just
    # blanket if mq patches are applied somewhere
    mq = getattr(repo, 'mq', None)
    if mq and mq.applied:
        raise util.Abort(_('source has mq patches applied'))

    parent = list(parent) + opts.get('rev', [])
    if opts.get('outgoing'):
        if len(parent) > 1:
            raise util.Abort(_('only one repo argument allowed with --outgoing'))
        elif parent:
            parent = parent[0]

        dest = ui.expandpath(parent or 'default-push', parent or 'default')
        dest, revs = hg.parseurl(dest, None)[:2]
        ui.status(_('comparing with %s\n') % util.hidepassword(dest))

        revs, checkout = hg.addbranchrevs(repo, repo, revs, None)
        other = hg.repository(hg.remoteui(repo, opts), dest)

        if revs:
            revs = [repo.lookup(rev) for rev in revs]

        parent = discovery.findcommonoutgoing(
            repo, other, [], force=opts.get('force')).missing[0:1]
    else:
        if opts.get('force'):
            raise util.Abort(_('--force only allowed with --outgoing'))

    if opts.get('continue', False):
        if len(parent) != 0:
            raise util.Abort(_('no arguments allowed with --continue'))
        (parentctxnode, created, replaced,
         tmpnodes, existing, rules, keep, tip, replacemap ) = readstate(repo)
        currentparent, wantnull = repo.dirstate.parents()
        parentctx = repo[parentctxnode]
        # discover any nodes the user has added in the interim
        newchildren = [c for c in parentctx.children()
                       if c.node() not in existing]
        action, currentnode = rules.pop(0)
        while newchildren:
            if action in ['f', 'fold', ]:
                tmpnodes.extend([n.node() for n in newchildren])
            else:
                created.extend([n.node() for n in newchildren])
            newchildren = filter(lambda x: x.node() not in existing,
                                 reduce(lambda x, y: x + y,
                                        map(lambda r: r.children(),
                                            newchildren)))
        m, a, r, d = repo.status()[:4]
        oldctx = repo[currentnode]
        message = oldctx.description()
        if action in ('e', 'edit', 'm', 'mess'):
            message = ui.edit(message, ui.username())
        elif action in ('f', 'fold', ):
            message = 'fold-temp-revision %s' % currentnode
        new = None
        if m or a or r or d:
            new = repo.commit(text=message, user=oldctx.user(), date=oldctx.date(),
                              extra=oldctx.extra())

        if action in ('f', 'fold'):
            if new:
                tmpnodes.append(new)
            else:
                new = newchildren[-1]
            (parentctx, created_,
             replaced_, tmpnodes_, ) = finishfold(ui, repo,
                                                  parentctx, oldctx, new,
                                                  opts, newchildren)
            replaced.extend(replaced_)
            created.extend(created_)
            tmpnodes.extend(tmpnodes_)
        elif action not in ('d', 'drop'):
            if new != oldctx.node():
                replaced.append(oldctx.node())
            if new:
                if new != oldctx.node():
                    created.append(new)
                parentctx = repo[new]

    elif opts.get('abort', False):
        if len(parent) != 0:
            raise util.Abort(_('no arguments allowed with --abort'))
        (parentctxnode, created, replaced, tmpnodes,
         existing, rules, keep, tip, replacemap) = readstate(repo)
        ui.debug('restore wc to old tip %s\n' % node.hex(tip))
        hg.clean(repo, tip)
        ui.debug('should strip created nodes %s\n' %
                 ', '.join([node.hex(n)[:12] for n in created]))
        ui.debug('should strip temp nodes %s\n' %
                 ', '.join([node.hex(n)[:12] for n in tmpnodes]))
        for nodes in (created, tmpnodes, ):
            for n in reversed(nodes):
                try:
                    repair.strip(ui, repo, n)
                except error.LookupError:
                    pass
        os.unlink(os.path.join(repo.path, 'histedit-state'))
        return
    else:
        cmdutil.bailifchanged(repo)
        if os.path.exists(os.path.join(repo.path, 'histedit-state')):
            raise util.Abort(_('history edit already in progress, try '
                               '--continue or --abort'))

        tip, empty = repo.dirstate.parents()


        if len(parent) != 1:
            raise util.Abort(_('histedit requires exactly one parent revision'))
        parent = scmutil.revsingle(repo, parent[0]).node()

        keep = opts.get('keep', False)
        revs = between(repo, parent, tip, keep)

        ctxs = [repo[r] for r in revs]
        existing = [r.node() for r in ctxs]
        rules = opts.get('commands', '')
        if not rules:
            rules = '\n'.join([makedesc(c) for c in ctxs])
            rules += editcomment % (node.hex(parent)[:12], node.hex(tip)[:12], )
            rules = ui.edit(rules, ui.username())
            # Save edit rules in .hg/histedit-last-edit.txt in case
            # the user needs to ask for help after something
            # surprising happens.
            f = open(repo.join('histedit-last-edit.txt'), 'w')
            f.write(rules)
            f.close()
        else:
            f = open(rules)
            rules = f.read()
            f.close()
        rules = [l for l in (r.strip() for r in rules.splitlines())
                 if l and not l[0] == '#']
        rules = verifyrules(rules, repo, ctxs)

        parentctx = repo[parent].parents()[0]
        keep = opts.get('keep', False)
        replaced = []
        replacemap = {}
        tmpnodes = []
        created = []


    while rules:
        writestate(repo, parentctx.node(), created, replaced, tmpnodes, existing,
                   rules, keep, tip, replacemap)
        action, ha = rules.pop(0)
        (parentctx, created_,
         replaced_, tmpnodes_, ) = actiontable[action](ui, repo,
                                                       parentctx, ha,
                                                       opts)

        hexshort = lambda x: node.hex(x)[:12]

        if replaced_:
            clen, rlen = len(created_), len(replaced_)
            if clen == rlen == 1:
                ui.debug('histedit: exact replacement of %s with %s\n' % (
                    hexshort(replaced_[0]), hexshort(created_[0])))

                replacemap[replaced_[0]] = created_[0]
            elif clen > rlen:
                assert rlen == 1, ('unexpected replacement of '
                                   '%d changes with %d changes' % (rlen, clen))
                # made more changesets than we're replacing
                # TODO synthesize patch names for created patches
                replacemap[replaced_[0]] = created_[-1]
                ui.debug('histedit: created many, assuming %s replaced by %s' % (
                    hexshort(replaced_[0]), hexshort(created_[-1])))
            elif rlen > clen:
                if not created_:
                    # This must be a drop. Try and put our metadata on
                    # the parent change.
                    assert rlen == 1
                    r = replaced_[0]
                    ui.debug('histedit: %s seems replaced with nothing, '
                            'finding a parent\n' % (hexshort(r)))
                    pctx = repo[r].parents()[0]
                    if pctx.node() in replacemap:
                        ui.debug('histedit: parent is already replaced\n')
                        replacemap[r] = replacemap[pctx.node()]
                    else:
                        replacemap[r] = pctx.node()
                    ui.debug('histedit: %s best replaced by %s\n' % (
                        hexshort(r), hexshort(replacemap[r])))
                else:
                    assert len(created_) == 1
                    for r in replaced_:
                        ui.debug('histedit: %s replaced by %s\n' % (
                            hexshort(r), hexshort(created_[0])))
                        replacemap[r] = created_[0]
            else:
                assert False, (
                    'Unhandled case in replacement mapping! '
                    'replacing %d changes with %d changes' % (rlen, clen))
        created.extend(created_)
        replaced.extend(replaced_)
        tmpnodes.extend(tmpnodes_)

    hg.update(repo, parentctx.node())

    if not keep:
        if replacemap:
            ui.note('histedit: Should update metadata for the following '
                    'changes:\n')

            def copybms(old, new):
                if old in tmpnodes or old in created:
                    # can't have any metadata we'd want to update
                    return
                while new in replacemap:
                    new = replacemap[new]
                ui.note('histedit:  %s to %s\n' % (hexshort(old), hexshort(new)))
                octx = repo[old]
                marks = octx.bookmarks()
                if marks:
                    ui.note('histedit:     moving bookmarks %s\n' %
                            ', '.join(marks))
                    for mark in marks:
                        repo._bookmarks[mark] = new
                    bookmarks.write(repo)

            # We assume that bookmarks on the tip should remain
            # tipmost, but bookmarks on non-tip changesets should go
            # to their most reasonable successor. As a result, find
            # the old tip and new tip and copy those bookmarks first,
            # then do the rest of the bookmark copies.
            oldtip = sorted(replacemap.keys(), key=repo.changelog.rev)[-1]
            newtip = sorted(replacemap.values(), key=repo.changelog.rev)[-1]
            copybms(oldtip, newtip)

            for old, new in replacemap.iteritems():
                copybms(old, new)
                # TODO update mq state

        ui.debug('should strip replaced nodes %s\n' %
                 ', '.join([node.hex(n)[:12] for n in replaced]))
        for n in sorted(replaced, key=lambda x: repo[x].rev()):
            try:
                repair.strip(ui, repo, n)
            except error.LookupError:
                pass

    ui.debug('should strip temp nodes %s\n' %
             ', '.join([node.hex(n)[:12] for n in tmpnodes]))
    for n in reversed(tmpnodes):
        try:
            repair.strip(ui, repo, n)
        except error.LookupError:
            pass
    os.unlink(os.path.join(repo.path, 'histedit-state'))
    if os.path.exists(repo.sjoin('undo')):
        os.unlink(repo.sjoin('undo'))


def writestate(repo, parentctxnode, created, replaced,
               tmpnodes, existing, rules, keep, oldtip, replacemap):
    fp = open(os.path.join(repo.path, 'histedit-state'), 'w')
    pickle.dump((parentctxnode, created, replaced,
                 tmpnodes, existing, rules, keep, oldtip, replacemap),
                fp)
    fp.close()

def readstate(repo):
    """Returns a tuple of (parentnode, created, replaced, tmp, existing, rules,
                           keep, oldtip, replacemap ).
    """
    fp = open(os.path.join(repo.path, 'histedit-state'))
    return pickle.load(fp)


def verifyrules(rules, repo, ctxs):
    """Verify that there exists exactly one edit rule per given changeset.

    Will abort if there are to many or too few rules, a malformed rule,
    or a rule on a changeset outside of the user-given range.
    """
    parsed = []
    first = True
    if len(rules) != len(ctxs):
        raise util.Abort(_('must specify a rule for each changeset once'))
    for r in rules:
        if ' ' not in r:
            raise util.Abort(_('malformed line "%s"') % r)
        action, rest = r.split(' ', 1)
        if ' ' in rest.strip():
            ha, rest = rest.split(' ', 1)
        else:
            ha = r.strip()
        try:
            if repo[ha] not in ctxs:
                raise util.Abort(_('may not use changesets other than the ones listed'))
        except error.RepoError:
            raise util.Abort(_('unknown changeset %s listed') % ha)
        if action not in actiontable:
            raise util.Abort(_('unknown action "%s"') % action)
        parsed.append([action, ha])
    return parsed


cmdtable = {
    "histedit":
        (histedit,
         [('', 'commands', '', _('Read history edits from the specified file.')),
          ('c', 'continue', False, _('continue an edit already in progress')),
          ('k', 'keep', False, _("don't strip old nodes after edit is complete")),
          ('', 'abort', False, _('abort an edit in progress')),
          ('o', 'outgoing', False, _('changesets not found in destination')),
          ('f', 'force', False, _('force outgoing even for unrelated repositories')),
          ('r', 'rev', [], _('first revision to be edited')),
          ],
         __doc__,
         ),
}