mercurial/shelve.py

dirstate-v2: actually fix the dirstate-v2 upgrade race

It looks like the previous fix for the dirstate-v2 upgrade race didn't work.
The problem is that it only recovers in case the size of the v1 `dirstate` file
is smaller than the `v2` one, whereas in real life it's always larger.

This commit changes the test to be more realistic, which reveals the crash,
and changes the code to fix the crash.

# shelve.py - save/restore working directory state
#
# Copyright 2013 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

"""save and restore changes to the working directory

The "hg shelve" command saves changes made to the working directory
and reverts those changes, resetting the working directory to a clean
state.

Later on, the "hg unshelve" command restores the changes saved by "hg
shelve". Changes can be restored even after updating to a different
parent, in which case Mercurial's merge machinery will resolve any
conflicts if necessary.

You can have more than one shelved change outstanding at a time; each
shelved change has a distinct name. For details, see the help for "hg
shelve".
"""

import collections
import io
import itertools
import stat

from .i18n import _
from .node import (
    bin,
    hex,
    nullrev,
)
from . import (
    bookmarks,
    bundle2,
    changegroup,
    cmdutil,
    discovery,
    error,
    exchange,
    hg,
    lock as lockmod,
    mdiff,
    merge,
    mergestate as mergestatemod,
    patch,
    phases,
    pycompat,
    repair,
    scmutil,
    templatefilters,
    util,
    vfs as vfsmod,
)
from .utils import (
    dateutil,
    stringutil,
)

backupdir = b'shelve-backup'
shelvedir = b'shelved'
shelvefileextensions = [b'hg', b'patch', b'shelve']

# we never need the user, so we use a
# generic user for all shelve operations
shelveuser = b'shelve@localhost'


class ShelfDir:
    def __init__(self, repo, for_backups=False):
        if for_backups:
            self.vfs = vfsmod.vfs(repo.vfs.join(backupdir))
        else:
            self.vfs = vfsmod.vfs(repo.vfs.join(shelvedir))

    def get(self, name):
        return Shelf(self.vfs, name)

    def listshelves(self):
        """return all shelves in repo as list of (time, name)"""
        try:
            names = self.vfs.listdir()
        except FileNotFoundError:
            return []
        info = []
        seen = set()
        for filename in names:
            name = filename.rsplit(b'.', 1)[0]
            if name in seen:
                continue
            seen.add(name)
            shelf = self.get(name)
            if not shelf.exists():
                continue
            mtime = shelf.mtime()
            info.append((mtime, name))
        return sorted(info, reverse=True)


def _use_internal_phase(repo):
    return (
        phases.supportinternal(repo)
        and repo.ui.config(b'shelve', b'store') == b'internal'
    )


def _target_phase(repo):
    return phases.internal if _use_internal_phase(repo) else phases.secret


class Shelf:
    """Represents a shelf, including possibly multiple files storing it.

    Old shelves will have a .patch and a .hg file. Newer shelves will
    also have a .shelve file. This class abstracts away some of the
    differences and lets you work with the shelf as a whole.
    """

    def __init__(self, vfs, name):
        self.vfs = vfs
        self.name = name

    def exists(self):
        return self._exists(b'.shelve') or self._exists(b'.patch', b'.hg')

    def _exists(self, *exts):
        return all(self.vfs.exists(self.name + ext) for ext in exts)

    def mtime(self):
        try:
            return self._stat(b'.shelve')[stat.ST_MTIME]
        except FileNotFoundError:
            return self._stat(b'.patch')[stat.ST_MTIME]

    def _stat(self, ext):
        return self.vfs.stat(self.name + ext)

    def writeinfo(self, info):
        scmutil.simplekeyvaluefile(self.vfs, self.name + b'.shelve').write(info)

    def hasinfo(self):
        return self.vfs.exists(self.name + b'.shelve')

    def readinfo(self):
        return scmutil.simplekeyvaluefile(
            self.vfs, self.name + b'.shelve'
        ).read()

    def writebundle(self, repo, bases, node):
        cgversion = changegroup.safeversion(repo)
        if cgversion == b'01':
            btype = b'HG10BZ'
            compression = None
        else:
            btype = b'HG20'
            compression = b'BZ'

        repo = repo.unfiltered()

        outgoing = discovery.outgoing(
            repo, missingroots=bases, ancestorsof=[node]
        )
        cg = changegroup.makechangegroup(repo, outgoing, cgversion, b'shelve')

        bundle_filename = self.vfs.join(self.name + b'.hg')
        bundle2.writebundle(
            repo.ui,
            cg,
            bundle_filename,
            btype,
            self.vfs,
            compression=compression,
        )

    def applybundle(self, repo, tr):
        filename = self.name + b'.hg'
        fp = self.vfs(filename)
        try:
            targetphase = _target_phase(repo)
            gen = exchange.readbundle(repo.ui, fp, filename, self.vfs)
            pretip = repo[b'tip']
            bundle2.applybundle(
                repo,
                gen,
                tr,
                source=b'unshelve',
                url=b'bundle:' + self.vfs.join(filename),
                targetphase=targetphase,
            )
            shelvectx = repo[b'tip']
            if pretip == shelvectx:
                shelverev = tr.changes[b'revduplicates'][-1]
                shelvectx = repo[shelverev]
            return shelvectx
        finally:
            fp.close()

    def open_patch(self, mode=b'rb'):
        return self.vfs(self.name + b'.patch', mode)

    def patch_from_node(self, repo, node):
        repo = repo.unfiltered()
        match = _optimized_match(repo, node)
        fp = io.BytesIO()
        cmdutil.exportfile(
            repo,
            [node],
            fp,
            opts=mdiff.diffopts(git=True),
            match=match,
        )
        fp.seek(0)
        return fp

    def load_patch(self, repo):
        try:
            # prefer node-based shelf
            return self.patch_from_node(repo, self.readinfo()[b'node'])
        except (FileNotFoundError, error.RepoLookupError):
            return self.open_patch()

    def _backupfilename(self, backupvfs, filename):
        def gennames(base):
            yield base
            base, ext = base.rsplit(b'.', 1)
            for i in itertools.count(1):
                yield b'%s-%d.%s' % (base, i, ext)

        for n in gennames(filename):
            if not backupvfs.exists(n):
                return backupvfs.join(n)

    def movetobackup(self, backupvfs):
        if not backupvfs.isdir():
            backupvfs.makedir()
        for suffix in shelvefileextensions:
            filename = self.name + b'.' + suffix
            if self.vfs.exists(filename):
                util.rename(
                    self.vfs.join(filename),
                    self._backupfilename(backupvfs, filename),
                )

    def delete(self):
        for ext in shelvefileextensions:
            self.vfs.tryunlink(self.name + b'.' + ext)

    def changed_files(self, ui, repo):
        try:
            ctx = repo.unfiltered()[self.readinfo()[b'node']]
            return ctx.files()
        except (FileNotFoundError, error.RepoLookupError):
            filename = self.vfs.join(self.name + b'.patch')
            return patch.changedfiles(ui, repo, filename)


def _optimized_match(repo, node):
    """
    Create a matcher so that prefetch doesn't attempt to fetch
    the entire repository pointlessly, and as an optimisation
    for movedirstate, if needed.
    """
    return scmutil.matchfiles(repo, repo[node].files())


class shelvedstate:
    """Handle persistence during unshelving operations.

    Handles saving and restoring a shelved state. Ensures that different
    versions of a shelved state are possible and handles them appropriately.
    """

    _version = 2
    _filename = b'shelvedstate'
    _keep = b'keep'
    _nokeep = b'nokeep'
    # colon is essential to differentiate from a real bookmark name
    _noactivebook = b':no-active-bookmark'
    _interactive = b'interactive'

    @classmethod
    def _verifyandtransform(cls, d):
        """Some basic shelvestate syntactic verification and transformation"""
        try:
            d[b'originalwctx'] = bin(d[b'originalwctx'])
            d[b'pendingctx'] = bin(d[b'pendingctx'])
            d[b'parents'] = [bin(h) for h in d[b'parents'].split(b' ') if h]
            d[b'nodestoremove'] = [
                bin(h) for h in d[b'nodestoremove'].split(b' ') if h
            ]
        except (ValueError, KeyError) as err:
            raise error.CorruptedState(stringutil.forcebytestr(err))

    @classmethod
    def _getversion(cls, repo):
        """Read version information from shelvestate file"""
        fp = repo.vfs(cls._filename)
        try:
            version = int(fp.readline().strip())
        except ValueError as err:
            raise error.CorruptedState(stringutil.forcebytestr(err))
        finally:
            fp.close()
        return version

    @classmethod
    def _readold(cls, repo):
        """Read the old position-based version of a shelvestate file"""
        # Order is important, because old shelvestate file uses it
        # to detemine values of fields (i.g. name is on the second line,
        # originalwctx is on the third and so forth). Please do not change.
        keys = [
            b'version',
            b'name',
            b'originalwctx',
            b'pendingctx',
            b'parents',
            b'nodestoremove',
            b'branchtorestore',
            b'keep',
            b'activebook',
        ]
        # this is executed only seldomly, so it is not a big deal
        # that we open this file twice
        fp = repo.vfs(cls._filename)
        d = {}
        try:
            for key in keys:
                d[key] = fp.readline().strip()
        finally:
            fp.close()
        return d

    @classmethod
    def load(cls, repo):
        version = cls._getversion(repo)
        if version < cls._version:
            d = cls._readold(repo)
        elif version == cls._version:
            d = scmutil.simplekeyvaluefile(repo.vfs, cls._filename).read(
                firstlinenonkeyval=True
            )
        else:
            raise error.Abort(
                _(
                    b'this version of shelve is incompatible '
                    b'with the version used in this repo'
                )
            )

        cls._verifyandtransform(d)
        try:
            obj = cls()
            obj.name = d[b'name']
            obj.wctx = repo[d[b'originalwctx']]
            obj.pendingctx = repo[d[b'pendingctx']]
            obj.parents = d[b'parents']
            obj.nodestoremove = d[b'nodestoremove']
            obj.branchtorestore = d.get(b'branchtorestore', b'')
            obj.keep = d.get(b'keep') == cls._keep
            obj.activebookmark = b''
            if d.get(b'activebook', b'') != cls._noactivebook:
                obj.activebookmark = d.get(b'activebook', b'')
            obj.interactive = d.get(b'interactive') == cls._interactive
        except (error.RepoLookupError, KeyError) as err:
            raise error.CorruptedState(pycompat.bytestr(err))

        return obj

    @classmethod
    def save(
        cls,
        repo,
        name,
        originalwctx,
        pendingctx,
        nodestoremove,
        branchtorestore,
        keep=False,
        activebook=b'',
        interactive=False,
    ):
        info = {
            b"name": name,
            b"originalwctx": hex(originalwctx.node()),
            b"pendingctx": hex(pendingctx.node()),
            b"parents": b' '.join([hex(p) for p in repo.dirstate.parents()]),
            b"nodestoremove": b' '.join([hex(n) for n in nodestoremove]),
            b"branchtorestore": branchtorestore,
            b"keep": cls._keep if keep else cls._nokeep,
            b"activebook": activebook or cls._noactivebook,
        }
        if interactive:
            info[b'interactive'] = cls._interactive
        scmutil.simplekeyvaluefile(repo.vfs, cls._filename).write(
            info, firstline=(b"%d" % cls._version)
        )

    @classmethod
    def clear(cls, repo):
        repo.vfs.unlinkpath(cls._filename, ignoremissing=True)


def cleanupoldbackups(repo):
    maxbackups = repo.ui.configint(b'shelve', b'maxbackups')
    backup_dir = ShelfDir(repo, for_backups=True)
    hgfiles = backup_dir.listshelves()
    if maxbackups > 0 and maxbackups < len(hgfiles):
        bordermtime = hgfiles[maxbackups - 1][0]
    else:
        bordermtime = None
    for mtime, name in hgfiles[maxbackups:]:
        if mtime == bordermtime:
            # keep it, because timestamp can't decide exact order of backups
            continue
        backup_dir.get(name).delete()


def _backupactivebookmark(repo):
    activebookmark = repo._activebookmark
    if activebookmark:
        bookmarks.deactivate(repo)
    return activebookmark


def _restoreactivebookmark(repo, mark):
    if mark:
        bookmarks.activate(repo, mark)


def _aborttransaction(repo, tr):
    """Abort current transaction for shelve/unshelve, but keep dirstate"""
    # disable the transaction invalidation of the dirstate, to preserve the
    # current change in memory.
    ds = repo.dirstate
    # The assert below check that nobody else did such wrapping.
    #
    # These is not such other wrapping currently, but if someone try to
    # implement one in the future, this will explicitly break here instead of
    # misbehaving in subtle ways.
    current_branch = ds.branch()
    assert 'invalidate' not in vars(ds)
    try:
        # note : we could simply disable the transaction abort callback, but
        # other code also tries to rollback and invalidate this.
        ds.invalidate = lambda: None
        tr.abort()
    finally:
        del ds.invalidate
    # manually write the change in memory since we can no longer rely on the
    # transaction to do so.
    assert repo.currenttransaction() is None
    repo.dirstate.write(None)
    ds.setbranch(current_branch, None)


def getshelvename(repo, parent, opts):
    """Decide on the name this shelve is going to have"""

    def gennames():
        yield label
        for i in itertools.count(1):
            yield b'%s-%02d' % (label, i)

    name = opts.get(b'name')
    label = repo._activebookmark or parent.branch() or b'default'
    # slashes aren't allowed in filenames, therefore we rename it
    label = label.replace(b'/', b'_')
    label = label.replace(b'\\', b'_')
    # filenames must not start with '.' as it should not be hidden
    if label.startswith(b'.'):
        label = label.replace(b'.', b'_', 1)

    if name:
        if ShelfDir(repo).get(name).exists():
            e = _(b"a shelved change named '%s' already exists") % name
            raise error.Abort(e)

        # ensure we are not creating a subdirectory or a hidden file
        if b'/' in name or b'\\' in name:
            raise error.Abort(
                _(b'shelved change names can not contain slashes')
            )
        if name.startswith(b'.'):
            raise error.Abort(_(b"shelved change names can not start with '.'"))

    else:
        shelf_dir = ShelfDir(repo)
        for n in gennames():
            if not shelf_dir.get(n).exists():
                name = n
                break

    return name


def mutableancestors(ctx):
    """return all mutable ancestors for ctx (included)

    Much faster than the revset ancestors(ctx) & draft()"""
    seen = {nullrev}
    visit = collections.deque()
    visit.append(ctx)
    while visit:
        ctx = visit.popleft()
        yield ctx.node()
        for parent in ctx.parents():
            rev = parent.rev()
            if rev not in seen:
                seen.add(rev)
                if parent.mutable():
                    visit.append(parent)


def getcommitfunc(extra, interactive, editor=False):
    def commitfunc(ui, repo, message, match, opts):
        hasmq = util.safehasattr(repo, 'mq')
        if hasmq:
            saved, repo.mq.checkapplied = repo.mq.checkapplied, False

        targetphase = _target_phase(repo)
        overrides = {(b'phases', b'new-commit'): targetphase}
        try:
            editor_ = False
            if editor:
                editor_ = cmdutil.getcommiteditor(
                    editform=b'shelve.shelve', **pycompat.strkwargs(opts)
                )
            with repo.ui.configoverride(overrides):
                return repo.commit(
                    message,
                    shelveuser,
                    opts.get(b'date'),
                    match,
                    editor=editor_,
                    extra=extra,
                )
        finally:
            if hasmq:
                repo.mq.checkapplied = saved

    def interactivecommitfunc(ui, repo, *pats, **opts):
        opts = pycompat.byteskwargs(opts)
        match = scmutil.match(repo[b'.'], pats, {})
        message = opts[b'message']
        return commitfunc(ui, repo, message, match, opts)

    return interactivecommitfunc if interactive else commitfunc


def _nothingtoshelvemessaging(ui, repo, pats, opts):
    stat = repo.status(match=scmutil.match(repo[None], pats, opts))
    if stat.deleted:
        ui.status(
            _(b"nothing changed (%d missing files, see 'hg status')\n")
            % len(stat.deleted)
        )
    else:
        ui.status(_(b"nothing changed\n"))


def _shelvecreatedcommit(repo, node, name, match):
    info = {b'node': hex(node)}
    shelf = ShelfDir(repo).get(name)
    shelf.writeinfo(info)
    bases = list(mutableancestors(repo[node]))
    shelf.writebundle(repo, bases, node)
    with shelf.open_patch(b'wb') as fp:
        cmdutil.exportfile(
            repo, [node], fp, opts=mdiff.diffopts(git=True), match=match
        )


def _includeunknownfiles(repo, pats, opts, extra):
    s = repo.status(match=scmutil.match(repo[None], pats, opts), unknown=True)
    if s.unknown:
        extra[b'shelve_unknown'] = b'\0'.join(s.unknown)
        repo[None].add(s.unknown)


def _finishshelve(repo, tr):
    if _use_internal_phase(repo):
        tr.close()
    else:
        _aborttransaction(repo, tr)


def createcmd(ui, repo, pats, opts):
    """subcommand that creates a new shelve"""
    with repo.wlock():
        cmdutil.checkunfinished(repo)
        return _docreatecmd(ui, repo, pats, opts)


def _docreatecmd(ui, repo, pats, opts):
    wctx = repo[None]
    parents = wctx.parents()
    parent = parents[0]
    origbranch = wctx.branch()

    if parent.rev() != nullrev:
        desc = b"changes to: %s" % parent.description().split(b'\n', 1)[0]
    else:
        desc = b'(changes in empty repository)'

    if not opts.get(b'message'):
        opts[b'message'] = desc

    lock = tr = activebookmark = None
    try:
        lock = repo.lock()

        # use an uncommitted transaction to generate the bundle to avoid
        # pull races. ensure we don't print the abort message to stderr.
        tr = repo.transaction(b'shelve', report=lambda x: None)

        interactive = opts.get(b'interactive', False)
        includeunknown = opts.get(b'unknown', False) and not opts.get(
            b'addremove', False
        )

        name = getshelvename(repo, parent, opts)
        activebookmark = _backupactivebookmark(repo)
        extra = {b'internal': b'shelve'}
        if includeunknown:
            with repo.dirstate.changing_files(repo):
                _includeunknownfiles(repo, pats, opts, extra)

        if _iswctxonnewbranch(repo) and not _isbareshelve(pats, opts):
            # In non-bare shelve we don't store newly created branch
            # at bundled commit
            repo.dirstate.setbranch(
                repo[b'.'].branch(), repo.currenttransaction()
            )

        commitfunc = getcommitfunc(extra, interactive, editor=True)
        if not interactive:
            node = cmdutil.commit(ui, repo, commitfunc, pats, opts)
        else:
            node = cmdutil.dorecord(
                ui,
                repo,
                commitfunc,
                None,
                False,
                cmdutil.recordfilter,
                *pats,
                **pycompat.strkwargs(opts)
            )
        if not node:
            _nothingtoshelvemessaging(ui, repo, pats, opts)
            return 1

        match = _optimized_match(repo, node)
        _shelvecreatedcommit(repo, node, name, match)

        ui.status(_(b'shelved as %s\n') % name)
        if opts[b'keep']:
            with repo.dirstate.changing_parents(repo):
                scmutil.movedirstate(repo, parent, match)
        else:
            hg.update(repo, parent.node())
            ms = mergestatemod.mergestate.read(repo)
            if not ms.unresolvedcount():
                ms.reset()

        if origbranch != repo[b'.'].branch() and not _isbareshelve(pats, opts):
            repo.dirstate.setbranch(origbranch, repo.currenttransaction())

        _finishshelve(repo, tr)
    finally:
        _restoreactivebookmark(repo, activebookmark)
        lockmod.release(tr, lock)


def _isbareshelve(pats, opts):
    return (
        not pats
        and not opts.get(b'interactive', False)
        and not opts.get(b'include', False)
        and not opts.get(b'exclude', False)
    )


def _iswctxonnewbranch(repo):
    return repo[None].branch() != repo[b'.'].branch()


def cleanupcmd(ui, repo):
    """subcommand that deletes all shelves"""

    with repo.wlock():
        shelf_dir = ShelfDir(repo)
        backupvfs = vfsmod.vfs(repo.vfs.join(backupdir))
        for _mtime, name in shelf_dir.listshelves():
            shelf_dir.get(name).movetobackup(backupvfs)
            cleanupoldbackups(repo)


def deletecmd(ui, repo, pats):
    """subcommand that deletes a specific shelve"""
    if not pats:
        raise error.InputError(_(b'no shelved changes specified!'))
    with repo.wlock():
        backupvfs = vfsmod.vfs(repo.vfs.join(backupdir))
        for name in pats:
            shelf = ShelfDir(repo).get(name)
            if not shelf.exists():
                raise error.InputError(
                    _(b"shelved change '%s' not found") % name
                )
            shelf.movetobackup(backupvfs)
            cleanupoldbackups(repo)


def listcmd(ui, repo, pats, opts):
    """subcommand that displays the list of shelves"""
    pats = set(pats)
    width = 80
    if not ui.plain():
        width = ui.termwidth()
    namelabel = b'shelve.newest'
    ui.pager(b'shelve')
    shelf_dir = ShelfDir(repo)
    for mtime, name in shelf_dir.listshelves():
        if pats and name not in pats:
            continue
        ui.write(name, label=namelabel)
        namelabel = b'shelve.name'
        if ui.quiet:
            ui.write(b'\n')
            continue
        ui.write(b' ' * (16 - len(name)))
        used = 16
        date = dateutil.makedate(mtime)
        age = b'(%s)' % templatefilters.age(date, abbrev=True)
        ui.write(age, label=b'shelve.age')
        ui.write(b' ' * (12 - len(age)))
        used += 12
        with shelf_dir.get(name).load_patch(repo) as fp:
            while True:
                line = fp.readline()
                if not line:
                    break
                if not line.startswith(b'#'):
                    desc = line.rstrip()
                    if ui.formatted():
                        desc = stringutil.ellipsis(desc, width - used)
                    ui.write(desc)
                    break
            ui.write(b'\n')
            if not (opts[b'patch'] or opts[b'stat']):
                continue
            difflines = fp.readlines()
            if opts[b'patch']:
                for chunk, label in patch.difflabel(iter, difflines):
                    ui.write(chunk, label=label)
            if opts[b'stat']:
                for chunk, label in patch.diffstatui(difflines, width=width):
                    ui.write(chunk, label=label)


def patchcmds(ui, repo, pats, opts):
    """subcommand that displays shelves"""
    shelf_dir = ShelfDir(repo)
    if len(pats) == 0:
        shelves = shelf_dir.listshelves()
        if not shelves:
            raise error.Abort(_(b"there are no shelves to show"))
        mtime, name = shelves[0]
        pats = [name]

    for shelfname in pats:
        if not shelf_dir.get(shelfname).exists():
            raise error.Abort(_(b"cannot find shelf %s") % shelfname)

    listcmd(ui, repo, pats, opts)


def checkparents(repo, state):
    """check parent while resuming an unshelve"""
    if state.parents != repo.dirstate.parents():
        raise error.Abort(
            _(b'working directory parents do not match unshelve state')
        )


def _loadshelvedstate(ui, repo, opts):
    try:
        state = shelvedstate.load(repo)
        if opts.get(b'keep') is None:
            opts[b'keep'] = state.keep
    except FileNotFoundError:
        cmdutil.wrongtooltocontinue(repo, _(b'unshelve'))
    except error.CorruptedState as err:
        ui.debug(pycompat.bytestr(err) + b'\n')
        if opts.get(b'continue'):
            msg = _(b'corrupted shelved state file')
            hint = _(
                b'please run hg unshelve --abort to abort unshelve '
                b'operation'
            )
            raise error.Abort(msg, hint=hint)
        elif opts.get(b'abort'):
            shelvedstate.clear(repo)
            raise error.Abort(
                _(
                    b'could not read shelved state file, your '
                    b'working copy may be in an unexpected state\n'
                    b'please update to some commit\n'
                )
            )
    return state


def unshelveabort(ui, repo, state):
    """subcommand that abort an in-progress unshelve"""
    with repo.lock():
        try:
            checkparents(repo, state)

            merge.clean_update(state.pendingctx)
            if state.activebookmark and state.activebookmark in repo._bookmarks:
                bookmarks.activate(repo, state.activebookmark)
            mergefiles(ui, repo, state.wctx, state.pendingctx)
            if not _use_internal_phase(repo):
                repair.strip(
                    ui, repo, state.nodestoremove, backup=False, topic=b'shelve'
                )
        finally:
            shelvedstate.clear(repo)
            ui.warn(_(b"unshelve of '%s' aborted\n") % state.name)


def hgabortunshelve(ui, repo):
    """logic to  abort unshelve using 'hg abort"""
    with repo.wlock():
        state = _loadshelvedstate(ui, repo, {b'abort': True})
        return unshelveabort(ui, repo, state)


def mergefiles(ui, repo, wctx, shelvectx):
    """updates to wctx and merges the changes from shelvectx into the
    dirstate."""
    with ui.configoverride({(b'ui', b'quiet'): True}):
        hg.update(repo, wctx.node())
        cmdutil.revert(ui, repo, shelvectx)


def restorebranch(ui, repo, branchtorestore):
    if branchtorestore and branchtorestore != repo.dirstate.branch():
        repo.dirstate.setbranch(branchtorestore, repo.currenttransaction())
        ui.status(
            _(b'marked working directory as branch %s\n') % branchtorestore
        )


def unshelvecleanup(ui, repo, name, opts):
    """remove related files after an unshelve"""
    if not opts.get(b'keep'):
        backupvfs = vfsmod.vfs(repo.vfs.join(backupdir))
        ShelfDir(repo).get(name).movetobackup(backupvfs)
        cleanupoldbackups(repo)


def unshelvecontinue(ui, repo, state, opts):
    """subcommand to continue an in-progress unshelve"""
    # We're finishing off a merge. First parent is our original
    # parent, second is the temporary "fake" commit we're unshelving.
    interactive = state.interactive
    basename = state.name
    with repo.lock():
        checkparents(repo, state)
        ms = mergestatemod.mergestate.read(repo)
        if ms.unresolvedcount():
            raise error.Abort(
                _(b"unresolved conflicts, can't continue"),
                hint=_(b"see 'hg resolve', then 'hg unshelve --continue'"),
            )

        shelvectx = repo[state.parents[1]]
        pendingctx = state.pendingctx

        with repo.dirstate.changing_parents(repo):
            repo.setparents(state.pendingctx.node(), repo.nullid)
            repo.dirstate.write(repo.currenttransaction())

        targetphase = _target_phase(repo)
        overrides = {(b'phases', b'new-commit'): targetphase}
        with repo.ui.configoverride(overrides, b'unshelve'):
            with repo.dirstate.changing_parents(repo):
                repo.setparents(state.parents[0], repo.nullid)
            newnode, ispartialunshelve = _createunshelvectx(
                ui, repo, shelvectx, basename, interactive, opts
            )

        if newnode is None:
            shelvectx = state.pendingctx
            msg = _(
                b'note: unshelved changes already existed '
                b'in the working copy\n'
            )
            ui.status(msg)
        else:
            # only strip the shelvectx if we produced one
            state.nodestoremove.append(newnode)
            shelvectx = repo[newnode]

        merge.update(pendingctx)
        mergefiles(ui, repo, state.wctx, shelvectx)
        restorebranch(ui, repo, state.branchtorestore)

        if not _use_internal_phase(repo):
            repair.strip(
                ui, repo, state.nodestoremove, backup=False, topic=b'shelve'
            )
        shelvedstate.clear(repo)
        if not ispartialunshelve:
            unshelvecleanup(ui, repo, state.name, opts)
        _restoreactivebookmark(repo, state.activebookmark)
        ui.status(_(b"unshelve of '%s' complete\n") % state.name)


def hgcontinueunshelve(ui, repo):
    """logic to resume unshelve using 'hg continue'"""
    with repo.wlock():
        state = _loadshelvedstate(ui, repo, {b'continue': True})
        return unshelvecontinue(ui, repo, state, {b'keep': state.keep})


def _commitworkingcopychanges(ui, repo, opts, tmpwctx):
    """Temporarily commit working copy changes before moving unshelve commit"""
    # Store pending changes in a commit and remember added in case a shelve
    # contains unknown files that are part of the pending change
    s = repo.status()
    addedbefore = frozenset(s.added)
    if not (s.modified or s.added or s.removed):
        return tmpwctx, addedbefore
    ui.status(
        _(
            b"temporarily committing pending changes "
            b"(restore with 'hg unshelve --abort')\n"
        )
    )
    extra = {b'internal': b'shelve'}
    commitfunc = getcommitfunc(extra=extra, interactive=False, editor=False)
    tempopts = {}
    tempopts[b'message'] = b"pending changes temporary commit"
    tempopts[b'date'] = opts.get(b'date')
    with ui.configoverride({(b'ui', b'quiet'): True}):
        node = cmdutil.commit(ui, repo, commitfunc, [], tempopts)
    tmpwctx = repo[node]
    return tmpwctx, addedbefore


def _unshelverestorecommit(ui, repo, tr, basename):
    """Recreate commit in the repository during the unshelve"""
    repo = repo.unfiltered()
    node = None
    shelf = ShelfDir(repo).get(basename)
    if shelf.hasinfo():
        node = shelf.readinfo()[b'node']
    if node is None or node not in repo:
        with ui.configoverride({(b'ui', b'quiet'): True}):
            shelvectx = shelf.applybundle(repo, tr)
        # We might not strip the unbundled changeset, so we should keep track of
        # the unshelve node in case we need to reuse it (eg: unshelve --keep)
        if node is None:
            info = {b'node': hex(shelvectx.node())}
            shelf.writeinfo(info)
    else:
        shelvectx = repo[node]

    return repo, shelvectx


def _createunshelvectx(ui, repo, shelvectx, basename, interactive, opts):
    """Handles the creation of unshelve commit and updates the shelve if it
    was partially unshelved.

    If interactive is:

      * False: Commits all the changes in the working directory.
      * True: Prompts the user to select changes to unshelve and commit them.
              Update the shelve with remaining changes.

    Returns the node of the new commit formed and a bool indicating whether
    the shelve was partially unshelved.Creates a commit ctx to unshelve
    interactively or non-interactively.

    The user might want to unshelve certain changes only from the stored
    shelve in interactive. So, we would create two commits. One with requested
    changes to unshelve at that time and the latter is shelved for future.

    Here, we return both the newnode which is created interactively and a
    bool to know whether the shelve is partly done or completely done.
    """
    opts[b'message'] = shelvectx.description()
    opts[b'interactive-unshelve'] = True
    pats = []
    if not interactive:
        newnode = repo.commit(
            text=shelvectx.description(),
            extra=shelvectx.extra(),
            user=shelvectx.user(),
            date=shelvectx.date(),
        )
        return newnode, False

    commitfunc = getcommitfunc(shelvectx.extra(), interactive=True, editor=True)
    newnode = cmdutil.dorecord(
        ui,
        repo,
        commitfunc,
        None,
        False,
        cmdutil.recordfilter,
        *pats,
        **pycompat.strkwargs(opts)
    )
    snode = repo.commit(
        text=shelvectx.description(),
        extra=shelvectx.extra(),
        user=shelvectx.user(),
    )
    if snode:
        m = _optimized_match(repo, snode)
        _shelvecreatedcommit(repo, snode, basename, m)

    return newnode, bool(snode)


def _rebaserestoredcommit(
    ui,
    repo,
    opts,
    tr,
    oldtiprev,
    basename,
    pctx,
    tmpwctx,
    shelvectx,
    branchtorestore,
    activebookmark,
):
    """Rebase restored commit from its original location to a destination"""
    # If the shelve is not immediately on top of the commit
    # we'll be merging with, rebase it to be on top.
    interactive = opts.get(b'interactive')
    if tmpwctx.node() == shelvectx.p1().node() and not interactive:
        # We won't skip on interactive mode because, the user might want to
        # unshelve certain changes only.
        return shelvectx, False

    overrides = {
        (b'ui', b'forcemerge'): opts.get(b'tool', b''),
        (b'phases', b'new-commit'): phases.secret,
    }
    with repo.ui.configoverride(overrides, b'unshelve'):
        ui.status(_(b'rebasing shelved changes\n'))
        stats = merge.graft(
            repo,
            shelvectx,
            labels=[
                b'working-copy',
                b'shelved change',
                b'parent of shelved change',
            ],
            keepconflictparent=True,
        )
        if stats.unresolvedcount:
            tr.close()

            nodestoremove = [
                repo.changelog.node(rev) for rev in range(oldtiprev, len(repo))
            ]
            shelvedstate.save(
                repo,
                basename,
                pctx,
                tmpwctx,
                nodestoremove,
                branchtorestore,
                opts.get(b'keep'),
                activebookmark,
                interactive,
            )
            raise error.ConflictResolutionRequired(b'unshelve')

        with repo.dirstate.changing_parents(repo):
            repo.setparents(tmpwctx.node(), repo.nullid)
        newnode, ispartialunshelve = _createunshelvectx(
            ui, repo, shelvectx, basename, interactive, opts
        )

        if newnode is None:
            shelvectx = tmpwctx
            msg = _(
                b'note: unshelved changes already existed '
                b'in the working copy\n'
            )
            ui.status(msg)
        else:
            shelvectx = repo[newnode]
            merge.update(tmpwctx)

    return shelvectx, ispartialunshelve


def _forgetunknownfiles(repo, shelvectx, addedbefore):
    # Forget any files that were unknown before the shelve, unknown before
    # unshelve started, but are now added.
    shelveunknown = shelvectx.extra().get(b'shelve_unknown')
    if not shelveunknown:
        return
    shelveunknown = frozenset(shelveunknown.split(b'\0'))
    addedafter = frozenset(repo.status().added)
    toforget = (addedafter & shelveunknown) - addedbefore
    repo[None].forget(toforget)


def _finishunshelve(repo, oldtiprev, tr, activebookmark):
    _restoreactivebookmark(repo, activebookmark)
    # The transaction aborting will strip all the commits for us,
    # but it doesn't update the inmemory structures, so addchangegroup
    # hooks still fire and try to operate on the missing commits.
    # Clean up manually to prevent this.
    repo.unfiltered().changelog.strip(oldtiprev, tr)
    _aborttransaction(repo, tr)


def _checkunshelveuntrackedproblems(ui, repo, shelvectx):
    """Check potential problems which may result from working
    copy having untracked changes."""
    wcdeleted = set(repo.status().deleted)
    shelvetouched = set(shelvectx.files())
    intersection = wcdeleted.intersection(shelvetouched)
    if intersection:
        m = _(b"shelved change touches missing files")
        hint = _(b"run hg status to see which files are missing")
        raise error.Abort(m, hint=hint)


def unshelvecmd(ui, repo, *shelved, **opts):
    opts = pycompat.byteskwargs(opts)
    abortf = opts.get(b'abort')
    continuef = opts.get(b'continue')
    interactive = opts.get(b'interactive')
    if not abortf and not continuef:
        cmdutil.checkunfinished(repo)
    shelved = list(shelved)
    if opts.get(b"name"):
        shelved.append(opts[b"name"])

    if interactive and opts.get(b'keep'):
        raise error.InputError(
            _(b'--keep on --interactive is not yet supported')
        )
    if abortf or continuef:
        if abortf and continuef:
            raise error.InputError(_(b'cannot use both abort and continue'))
        if shelved:
            raise error.InputError(
                _(
                    b'cannot combine abort/continue with '
                    b'naming a shelved change'
                )
            )
        if abortf and opts.get(b'tool', False):
            ui.warn(_(b'tool option will be ignored\n'))

        state = _loadshelvedstate(ui, repo, opts)
        if abortf:
            return unshelveabort(ui, repo, state)
        elif continuef and interactive:
            raise error.InputError(
                _(b'cannot use both continue and interactive')
            )
        elif continuef:
            return unshelvecontinue(ui, repo, state, opts)
    elif len(shelved) > 1:
        raise error.InputError(_(b'can only unshelve one change at a time'))
    elif not shelved:
        shelved = ShelfDir(repo).listshelves()
        if not shelved:
            raise error.StateError(_(b'no shelved changes to apply!'))
        basename = shelved[0][1]
        ui.status(_(b"unshelving change '%s'\n") % basename)
    else:
        basename = shelved[0]

    if not ShelfDir(repo).get(basename).exists():
        raise error.InputError(_(b"shelved change '%s' not found") % basename)

    return _dounshelve(ui, repo, basename, opts)


def _dounshelve(ui, repo, basename, opts):
    repo = repo.unfiltered()
    lock = tr = None
    try:
        lock = repo.lock()
        tr = repo.transaction(b'unshelve', report=lambda x: None)
        oldtiprev = len(repo)

        pctx = repo[b'.']
        # The goal is to have a commit structure like so:
        # ...-> pctx -> tmpwctx -> shelvectx
        # where tmpwctx is an optional commit with the user's pending changes
        # and shelvectx is the unshelved changes. Then we merge it all down
        # to the original pctx.

        activebookmark = _backupactivebookmark(repo)
        tmpwctx, addedbefore = _commitworkingcopychanges(ui, repo, opts, pctx)
        repo, shelvectx = _unshelverestorecommit(ui, repo, tr, basename)
        _checkunshelveuntrackedproblems(ui, repo, shelvectx)
        branchtorestore = b''
        if shelvectx.branch() != shelvectx.p1().branch():
            branchtorestore = shelvectx.branch()

        shelvectx, ispartialunshelve = _rebaserestoredcommit(
            ui,
            repo,
            opts,
            tr,
            oldtiprev,
            basename,
            pctx,
            tmpwctx,
            shelvectx,
            branchtorestore,
            activebookmark,
        )
        overrides = {(b'ui', b'forcemerge'): opts.get(b'tool', b'')}
        with ui.configoverride(overrides, b'unshelve'):
            mergefiles(ui, repo, pctx, shelvectx)
        restorebranch(ui, repo, branchtorestore)
        shelvedstate.clear(repo)
        _finishunshelve(repo, oldtiprev, tr, activebookmark)
        with repo.dirstate.changing_files(repo):
            _forgetunknownfiles(repo, shelvectx, addedbefore)
        if not ispartialunshelve:
            unshelvecleanup(ui, repo, basename, opts)
    finally:
        if tr:
            tr.release()
        lockmod.release(lock)