diff -r cd7aaf344d83 -r 70d163b86316 mercurial/upgrade.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mercurial/upgrade.py	Fri Apr 07 18:53:17 2017 +0200
@@ -0,0 +1,758 @@
+# repair.py - functions for repository repair for mercurial
+#
+# Copyright 2005, 2006 Chris Mason <mason@suse.com>
+# Copyright 2007 Matt Mackall
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+
+from __future__ import absolute_import
+
+import stat
+import tempfile
+
+from .i18n import _
+from . import (
+    changelog,
+    error,
+    manifest,
+    revlog,
+    scmutil,
+    util,
+    vfs as vfsmod,
+)
+
+def upgraderequiredsourcerequirements(repo):
+    """Obtain requirements required to be present to upgrade a repo.
+
+    An upgrade will not be allowed if the repository doesn't have the
+    requirements returned by this function.
+    """
+    return set([
+        # Introduced in Mercurial 0.9.2.
+        'revlogv1',
+        # Introduced in Mercurial 0.9.2.
+        'store',
+    ])
+
+def upgradeblocksourcerequirements(repo):
+    """Obtain requirements that will prevent an upgrade from occurring.
+
+    An upgrade cannot be performed if the source repository contains a
+    requirements in the returned set.
+    """
+    return set([
+        # The upgrade code does not yet support these experimental features.
+        # This is an artificial limitation.
+        'manifestv2',
+        'treemanifest',
+        # This was a precursor to generaldelta and was never enabled by default.
+        # It should (hopefully) not exist in the wild.
+        'parentdelta',
+        # Upgrade should operate on the actual store, not the shared link.
+        'shared',
+    ])
+
+def upgradesupportremovedrequirements(repo):
+    """Obtain requirements that can be removed during an upgrade.
+
+    If an upgrade were to create a repository that dropped a requirement,
+    the dropped requirement must appear in the returned set for the upgrade
+    to be allowed.
+    """
+    return set()
+
+def upgradesupporteddestrequirements(repo):
+    """Obtain requirements that upgrade supports in the destination.
+
+    If the result of the upgrade would create requirements not in this set,
+    the upgrade is disallowed.
+
+    Extensions should monkeypatch this to add their custom requirements.
+    """
+    return set([
+        'dotencode',
+        'fncache',
+        'generaldelta',
+        'revlogv1',
+        'store',
+    ])
+
+def upgradeallowednewrequirements(repo):
+    """Obtain requirements that can be added to a repository during upgrade.
+
+    This is used to disallow proposed requirements from being added when
+    they weren't present before.
+
+    We use a list of allowed requirement additions instead of a list of known
+    bad additions because the whitelist approach is safer and will prevent
+    future, unknown requirements from accidentally being added.
+    """
+    return set([
+        'dotencode',
+        'fncache',
+        'generaldelta',
+    ])
+
+deficiency = 'deficiency'
+optimisation = 'optimization'
+
+class upgradeimprovement(object):
+    """Represents an improvement that can be made as part of an upgrade.
+
+    The following attributes are defined on each instance:
+
+    name
+       Machine-readable string uniquely identifying this improvement. It
+       will be mapped to an action later in the upgrade process.
+
+    type
+       Either ``deficiency`` or ``optimisation``. A deficiency is an obvious
+       problem. An optimization is an action (sometimes optional) that
+       can be taken to further improve the state of the repository.
+
+    description
+       Message intended for humans explaining the improvement in more detail,
+       including the implications of it. For ``deficiency`` types, should be
+       worded in the present tense. For ``optimisation`` types, should be
+       worded in the future tense.
+
+    upgrademessage
+       Message intended for humans explaining what an upgrade addressing this
+       issue will do. Should be worded in the future tense.
+
+    fromdefault (``deficiency`` types only)
+       Boolean indicating whether the current (deficient) state deviates
+       from Mercurial's default configuration.
+
+    fromconfig (``deficiency`` types only)
+       Boolean indicating whether the current (deficient) state deviates
+       from the current Mercurial configuration.
+    """
+    def __init__(self, name, type, description, upgrademessage, **kwargs):
+        self.name = name
+        self.type = type
+        self.description = description
+        self.upgrademessage = upgrademessage
+
+        for k, v in kwargs.items():
+            setattr(self, k, v)
+
+def upgradefindimprovements(repo):
+    """Determine improvements that can be made to the repo during upgrade.
+
+    Returns a list of ``upgradeimprovement`` describing repository deficiencies
+    and optimizations.
+    """
+    # Avoid cycle: cmdutil -> repair -> localrepo -> cmdutil
+    from . import localrepo
+
+    newreporeqs = localrepo.newreporequirements(repo)
+
+    improvements = []
+
+    # We could detect lack of revlogv1 and store here, but they were added
+    # in 0.9.2 and we don't support upgrading repos without these
+    # requirements, so let's not bother.
+
+    if 'fncache' not in repo.requirements:
+        improvements.append(upgradeimprovement(
+            name='fncache',
+            type=deficiency,
+            description=_('long and reserved filenames may not work correctly; '
+                          'repository performance is sub-optimal'),
+            upgrademessage=_('repository will be more resilient to storing '
+                             'certain paths and performance of certain '
+                             'operations should be improved'),
+            fromdefault=True,
+            fromconfig='fncache' in newreporeqs))
+
+    if 'dotencode' not in repo.requirements:
+        improvements.append(upgradeimprovement(
+            name='dotencode',
+            type=deficiency,
+            description=_('storage of filenames beginning with a period or '
+                          'space may not work correctly'),
+            upgrademessage=_('repository will be better able to store files '
+                             'beginning with a space or period'),
+            fromdefault=True,
+            fromconfig='dotencode' in newreporeqs))
+
+    if 'generaldelta' not in repo.requirements:
+        improvements.append(upgradeimprovement(
+            name='generaldelta',
+            type=deficiency,
+            description=_('deltas within internal storage are unable to '
+                          'choose optimal revisions; repository is larger and '
+                          'slower than it could be; interaction with other '
+                          'repositories may require extra network and CPU '
+                          'resources, making "hg push" and "hg pull" slower'),
+            upgrademessage=_('repository storage will be able to create '
+                             'optimal deltas; new repository data will be '
+                             'smaller and read times should decrease; '
+                             'interacting with other repositories using this '
+                             'storage model should require less network and '
+                             'CPU resources, making "hg push" and "hg pull" '
+                             'faster'),
+            fromdefault=True,
+            fromconfig='generaldelta' in newreporeqs))
+
+    # Mercurial 4.0 changed changelogs to not use delta chains. Search for
+    # changelogs with deltas.
+    cl = repo.changelog
+    for rev in cl:
+        chainbase = cl.chainbase(rev)
+        if chainbase != rev:
+            improvements.append(upgradeimprovement(
+                name='removecldeltachain',
+                type=deficiency,
+                description=_('changelog storage is using deltas instead of '
+                              'raw entries; changelog reading and any '
+                              'operation relying on changelog data are slower '
+                              'than they could be'),
+                upgrademessage=_('changelog storage will be reformated to '
+                                 'store raw entries; changelog reading will be '
+                                 'faster; changelog size may be reduced'),
+                fromdefault=True,
+                fromconfig=True))
+            break
+
+    # Now for the optimizations.
+
+    # These are unconditionally added. There is logic later that figures out
+    # which ones to apply.
+
+    improvements.append(upgradeimprovement(
+        name='redeltaparent',
+        type=optimisation,
+        description=_('deltas within internal storage will be recalculated to '
+                      'choose an optimal base revision where this was not '
+                      'already done; the size of the repository may shrink and '
+                      'various operations may become faster; the first time '
+                      'this optimization is performed could slow down upgrade '
+                      'execution considerably; subsequent invocations should '
+                      'not run noticeably slower'),
+        upgrademessage=_('deltas within internal storage will choose a new '
+                         'base revision if needed')))
+
+    improvements.append(upgradeimprovement(
+        name='redeltamultibase',
+        type=optimisation,
+        description=_('deltas within internal storage will be recalculated '
+                      'against multiple base revision and the smallest '
+                      'difference will be used; the size of the repository may '
+                      'shrink significantly when there are many merges; this '
+                      'optimization will slow down execution in proportion to '
+                      'the number of merges in the repository and the amount '
+                      'of files in the repository; this slow down should not '
+                      'be significant unless there are tens of thousands of '
+                      'files and thousands of merges'),
+        upgrademessage=_('deltas within internal storage will choose an '
+                         'optimal delta by computing deltas against multiple '
+                         'parents; may slow down execution time '
+                         'significantly')))
+
+    improvements.append(upgradeimprovement(
+        name='redeltaall',
+        type=optimisation,
+        description=_('deltas within internal storage will always be '
+                      'recalculated without reusing prior deltas; this will '
+                      'likely make execution run several times slower; this '
+                      'optimization is typically not needed'),
+        upgrademessage=_('deltas within internal storage will be fully '
+                         'recomputed; this will likely drastically slow down '
+                         'execution time')))
+
+    return improvements
+
+def upgradedetermineactions(repo, improvements, sourcereqs, destreqs,
+                            optimize):
+    """Determine upgrade actions that will be performed.
+
+    Given a list of improvements as returned by ``upgradefindimprovements``,
+    determine the list of upgrade actions that will be performed.
+
+    The role of this function is to filter improvements if needed, apply
+    recommended optimizations from the improvements list that make sense,
+    etc.
+
+    Returns a list of action names.
+    """
+    newactions = []
+
+    knownreqs = upgradesupporteddestrequirements(repo)
+
+    for i in improvements:
+        name = i.name
+
+        # If the action is a requirement that doesn't show up in the
+        # destination requirements, prune the action.
+        if name in knownreqs and name not in destreqs:
+            continue
+
+        if i.type == deficiency:
+            newactions.append(name)
+
+    newactions.extend(o for o in sorted(optimize) if o not in newactions)
+
+    # FUTURE consider adding some optimizations here for certain transitions.
+    # e.g. adding generaldelta could schedule parent redeltas.
+
+    return newactions
+
+def _revlogfrompath(repo, path):
+    """Obtain a revlog from a repo path.
+
+    An instance of the appropriate class is returned.
+    """
+    if path == '00changelog.i':
+        return changelog.changelog(repo.svfs)
+    elif path.endswith('00manifest.i'):
+        mandir = path[:-len('00manifest.i')]
+        return manifest.manifestrevlog(repo.svfs, dir=mandir)
+    else:
+        # Filelogs don't do anything special with settings. So we can use a
+        # vanilla revlog.
+        return revlog.revlog(repo.svfs, path)
+
+def _copyrevlogs(ui, srcrepo, dstrepo, tr, deltareuse, aggressivemergedeltas):
+    """Copy revlogs between 2 repos."""
+    revcount = 0
+    srcsize = 0
+    srcrawsize = 0
+    dstsize = 0
+    fcount = 0
+    frevcount = 0
+    fsrcsize = 0
+    frawsize = 0
+    fdstsize = 0
+    mcount = 0
+    mrevcount = 0
+    msrcsize = 0
+    mrawsize = 0
+    mdstsize = 0
+    crevcount = 0
+    csrcsize = 0
+    crawsize = 0
+    cdstsize = 0
+
+    # Perform a pass to collect metadata. This validates we can open all
+    # source files and allows a unified progress bar to be displayed.
+    for unencoded, encoded, size in srcrepo.store.walk():
+        if unencoded.endswith('.d'):
+            continue
+
+        rl = _revlogfrompath(srcrepo, unencoded)
+        revcount += len(rl)
+
+        datasize = 0
+        rawsize = 0
+        idx = rl.index
+        for rev in rl:
+            e = idx[rev]
+            datasize += e[1]
+            rawsize += e[2]
+
+        srcsize += datasize
+        srcrawsize += rawsize
+
+        # This is for the separate progress bars.
+        if isinstance(rl, changelog.changelog):
+            crevcount += len(rl)
+            csrcsize += datasize
+            crawsize += rawsize
+        elif isinstance(rl, manifest.manifestrevlog):
+            mcount += 1
+            mrevcount += len(rl)
+            msrcsize += datasize
+            mrawsize += rawsize
+        elif isinstance(rl, revlog.revlog):
+            fcount += 1
+            frevcount += len(rl)
+            fsrcsize += datasize
+            frawsize += rawsize
+
+    if not revcount:
+        return
+
+    ui.write(_('migrating %d total revisions (%d in filelogs, %d in manifests, '
+               '%d in changelog)\n') %
+             (revcount, frevcount, mrevcount, crevcount))
+    ui.write(_('migrating %s in store; %s tracked data\n') % (
+             (util.bytecount(srcsize), util.bytecount(srcrawsize))))
+
+    # Used to keep track of progress.
+    progress = []
+    def oncopiedrevision(rl, rev, node):
+        progress[1] += 1
+        srcrepo.ui.progress(progress[0], progress[1], total=progress[2])
+
+    # Do the actual copying.
+    # FUTURE this operation can be farmed off to worker processes.
+    seen = set()
+    for unencoded, encoded, size in srcrepo.store.walk():
+        if unencoded.endswith('.d'):
+            continue
+
+        oldrl = _revlogfrompath(srcrepo, unencoded)
+        newrl = _revlogfrompath(dstrepo, unencoded)
+
+        if isinstance(oldrl, changelog.changelog) and 'c' not in seen:
+            ui.write(_('finished migrating %d manifest revisions across %d '
+                       'manifests; change in size: %s\n') %
+                     (mrevcount, mcount, util.bytecount(mdstsize - msrcsize)))
+
+            ui.write(_('migrating changelog containing %d revisions '
+                       '(%s in store; %s tracked data)\n') %
+                     (crevcount, util.bytecount(csrcsize),
+                      util.bytecount(crawsize)))
+            seen.add('c')
+            progress[:] = [_('changelog revisions'), 0, crevcount]
+        elif isinstance(oldrl, manifest.manifestrevlog) and 'm' not in seen:
+            ui.write(_('finished migrating %d filelog revisions across %d '
+                       'filelogs; change in size: %s\n') %
+                     (frevcount, fcount, util.bytecount(fdstsize - fsrcsize)))
+
+            ui.write(_('migrating %d manifests containing %d revisions '
+                       '(%s in store; %s tracked data)\n') %
+                     (mcount, mrevcount, util.bytecount(msrcsize),
+                      util.bytecount(mrawsize)))
+            seen.add('m')
+            progress[:] = [_('manifest revisions'), 0, mrevcount]
+        elif 'f' not in seen:
+            ui.write(_('migrating %d filelogs containing %d revisions '
+                       '(%s in store; %s tracked data)\n') %
+                     (fcount, frevcount, util.bytecount(fsrcsize),
+                      util.bytecount(frawsize)))
+            seen.add('f')
+            progress[:] = [_('file revisions'), 0, frevcount]
+
+        ui.progress(progress[0], progress[1], total=progress[2])
+
+        ui.note(_('cloning %d revisions from %s\n') % (len(oldrl), unencoded))
+        oldrl.clone(tr, newrl, addrevisioncb=oncopiedrevision,
+                    deltareuse=deltareuse,
+                    aggressivemergedeltas=aggressivemergedeltas)
+
+        datasize = 0
+        idx = newrl.index
+        for rev in newrl:
+            datasize += idx[rev][1]
+
+        dstsize += datasize
+
+        if isinstance(newrl, changelog.changelog):
+            cdstsize += datasize
+        elif isinstance(newrl, manifest.manifestrevlog):
+            mdstsize += datasize
+        else:
+            fdstsize += datasize
+
+    ui.progress(progress[0], None)
+
+    ui.write(_('finished migrating %d changelog revisions; change in size: '
+               '%s\n') % (crevcount, util.bytecount(cdstsize - csrcsize)))
+
+    ui.write(_('finished migrating %d total revisions; total change in store '
+               'size: %s\n') % (revcount, util.bytecount(dstsize - srcsize)))
+
+def _upgradefilterstorefile(srcrepo, dstrepo, requirements, path, mode, st):
+    """Determine whether to copy a store file during upgrade.
+
+    This function is called when migrating store files from ``srcrepo`` to
+    ``dstrepo`` as part of upgrading a repository.
+
+    Args:
+      srcrepo: repo we are copying from
+      dstrepo: repo we are copying to
+      requirements: set of requirements for ``dstrepo``
+      path: store file being examined
+      mode: the ``ST_MODE`` file type of ``path``
+      st: ``stat`` data structure for ``path``
+
+    Function should return ``True`` if the file is to be copied.
+    """
+    # Skip revlogs.
+    if path.endswith(('.i', '.d')):
+        return False
+    # Skip transaction related files.
+    if path.startswith('undo'):
+        return False
+    # Only copy regular files.
+    if mode != stat.S_IFREG:
+        return False
+    # Skip other skipped files.
+    if path in ('lock', 'fncache'):
+        return False
+
+    return True
+
+def _upgradefinishdatamigration(ui, srcrepo, dstrepo, requirements):
+    """Hook point for extensions to perform additional actions during upgrade.
+
+    This function is called after revlogs and store files have been copied but
+    before the new store is swapped into the original location.
+    """
+
+def _upgraderepo(ui, srcrepo, dstrepo, requirements, actions):
+    """Do the low-level work of upgrading a repository.
+
+    The upgrade is effectively performed as a copy between a source
+    repository and a temporary destination repository.
+
+    The source repository is unmodified for as long as possible so the
+    upgrade can abort at any time without causing loss of service for
+    readers and without corrupting the source repository.
+    """
+    assert srcrepo.currentwlock()
+    assert dstrepo.currentwlock()
+
+    ui.write(_('(it is safe to interrupt this process any time before '
+               'data migration completes)\n'))
+
+    if 'redeltaall' in actions:
+        deltareuse = revlog.revlog.DELTAREUSENEVER
+    elif 'redeltaparent' in actions:
+        deltareuse = revlog.revlog.DELTAREUSESAMEREVS
+    elif 'redeltamultibase' in actions:
+        deltareuse = revlog.revlog.DELTAREUSESAMEREVS
+    else:
+        deltareuse = revlog.revlog.DELTAREUSEALWAYS
+
+    with dstrepo.transaction('upgrade') as tr:
+        _copyrevlogs(ui, srcrepo, dstrepo, tr, deltareuse,
+                     'redeltamultibase' in actions)
+
+    # Now copy other files in the store directory.
+    for p, kind, st in srcrepo.store.vfs.readdir('', stat=True):
+        if not _upgradefilterstorefile(srcrepo, dstrepo, requirements,
+                                       p, kind, st):
+            continue
+
+        srcrepo.ui.write(_('copying %s\n') % p)
+        src = srcrepo.store.vfs.join(p)
+        dst = dstrepo.store.vfs.join(p)
+        util.copyfile(src, dst, copystat=True)
+
+    _upgradefinishdatamigration(ui, srcrepo, dstrepo, requirements)
+
+    ui.write(_('data fully migrated to temporary repository\n'))
+
+    backuppath = tempfile.mkdtemp(prefix='upgradebackup.', dir=srcrepo.path)
+    backupvfs = vfsmod.vfs(backuppath)
+
+    # Make a backup of requires file first, as it is the first to be modified.
+    util.copyfile(srcrepo.vfs.join('requires'), backupvfs.join('requires'))
+
+    # We install an arbitrary requirement that clients must not support
+    # as a mechanism to lock out new clients during the data swap. This is
+    # better than allowing a client to continue while the repository is in
+    # an inconsistent state.
+    ui.write(_('marking source repository as being upgraded; clients will be '
+               'unable to read from repository\n'))
+    scmutil.writerequires(srcrepo.vfs,
+                          srcrepo.requirements | set(['upgradeinprogress']))
+
+    ui.write(_('starting in-place swap of repository data\n'))
+    ui.write(_('replaced files will be backed up at %s\n') %
+             backuppath)
+
+    # Now swap in the new store directory. Doing it as a rename should make
+    # the operation nearly instantaneous and atomic (at least in well-behaved
+    # environments).
+    ui.write(_('replacing store...\n'))
+    tstart = util.timer()
+    util.rename(srcrepo.spath, backupvfs.join('store'))
+    util.rename(dstrepo.spath, srcrepo.spath)
+    elapsed = util.timer() - tstart
+    ui.write(_('store replacement complete; repository was inconsistent for '
+               '%0.1fs\n') % elapsed)
+
+    # We first write the requirements file. Any new requirements will lock
+    # out legacy clients.
+    ui.write(_('finalizing requirements file and making repository readable '
+               'again\n'))
+    scmutil.writerequires(srcrepo.vfs, requirements)
+
+    # The lock file from the old store won't be removed because nothing has a
+    # reference to its new location. So clean it up manually. Alternatively, we
+    # could update srcrepo.svfs and other variables to point to the new
+    # location. This is simpler.
+    backupvfs.unlink('store/lock')
+
+    return backuppath
+
+def upgraderepo(ui, repo, run=False, optimize=None):
+    """Upgrade a repository in place."""
+    # Avoid cycle: cmdutil -> repair -> localrepo -> cmdutil
+    from . import localrepo
+
+    optimize = set(optimize or [])
+    repo = repo.unfiltered()
+
+    # Ensure the repository can be upgraded.
+    missingreqs = upgraderequiredsourcerequirements(repo) - repo.requirements
+    if missingreqs:
+        raise error.Abort(_('cannot upgrade repository; requirement '
+                            'missing: %s') % _(', ').join(sorted(missingreqs)))
+
+    blockedreqs = upgradeblocksourcerequirements(repo) & repo.requirements
+    if blockedreqs:
+        raise error.Abort(_('cannot upgrade repository; unsupported source '
+                            'requirement: %s') %
+                          _(', ').join(sorted(blockedreqs)))
+
+    # FUTURE there is potentially a need to control the wanted requirements via
+    # command arguments or via an extension hook point.
+    newreqs = localrepo.newreporequirements(repo)
+
+    noremovereqs = (repo.requirements - newreqs -
+                   upgradesupportremovedrequirements(repo))
+    if noremovereqs:
+        raise error.Abort(_('cannot upgrade repository; requirement would be '
+                            'removed: %s') % _(', ').join(sorted(noremovereqs)))
+
+    noaddreqs = (newreqs - repo.requirements -
+                 upgradeallowednewrequirements(repo))
+    if noaddreqs:
+        raise error.Abort(_('cannot upgrade repository; do not support adding '
+                            'requirement: %s') %
+                          _(', ').join(sorted(noaddreqs)))
+
+    unsupportedreqs = newreqs - upgradesupporteddestrequirements(repo)
+    if unsupportedreqs:
+        raise error.Abort(_('cannot upgrade repository; do not support '
+                            'destination requirement: %s') %
+                          _(', ').join(sorted(unsupportedreqs)))
+
+    # Find and validate all improvements that can be made.
+    improvements = upgradefindimprovements(repo)
+    for i in improvements:
+        if i.type not in (deficiency, optimisation):
+            raise error.Abort(_('unexpected improvement type %s for %s') % (
+                i.type, i.name))
+
+    # Validate arguments.
+    unknownoptimize = optimize - set(i.name for i in improvements
+                                     if i.type == optimisation)
+    if unknownoptimize:
+        raise error.Abort(_('unknown optimization action requested: %s') %
+                          ', '.join(sorted(unknownoptimize)),
+                          hint=_('run without arguments to see valid '
+                                 'optimizations'))
+
+    actions = upgradedetermineactions(repo, improvements, repo.requirements,
+                                      newreqs, optimize)
+
+    def printrequirements():
+        ui.write(_('requirements\n'))
+        ui.write(_('   preserved: %s\n') %
+                 _(', ').join(sorted(newreqs & repo.requirements)))
+
+        if repo.requirements - newreqs:
+            ui.write(_('   removed: %s\n') %
+                     _(', ').join(sorted(repo.requirements - newreqs)))
+
+        if newreqs - repo.requirements:
+            ui.write(_('   added: %s\n') %
+                     _(', ').join(sorted(newreqs - repo.requirements)))
+
+        ui.write('\n')
+
+    def printupgradeactions():
+        for action in actions:
+            for i in improvements:
+                if i.name == action:
+                    ui.write('%s\n   %s\n\n' %
+                             (i.name, i.upgrademessage))
+
+    if not run:
+        fromdefault = []
+        fromconfig = []
+        optimizations = []
+
+        for i in improvements:
+            assert i.type in (deficiency, optimisation)
+            if i.type == deficiency:
+                if i.fromdefault:
+                    fromdefault.append(i)
+                if i.fromconfig:
+                    fromconfig.append(i)
+            else:
+                optimizations.append(i)
+
+        if fromdefault or fromconfig:
+            fromconfignames = set(x.name for x in fromconfig)
+            onlydefault = [i for i in fromdefault
+                           if i.name not in fromconfignames]
+
+            if fromconfig:
+                ui.write(_('repository lacks features recommended by '
+                           'current config options:\n\n'))
+                for i in fromconfig:
+                    ui.write('%s\n   %s\n\n' % (i.name, i.description))
+
+            if onlydefault:
+                ui.write(_('repository lacks features used by the default '
+                           'config options:\n\n'))
+                for i in onlydefault:
+                    ui.write('%s\n   %s\n\n' % (i.name, i.description))
+
+            ui.write('\n')
+        else:
+            ui.write(_('(no feature deficiencies found in existing '
+                       'repository)\n'))
+
+        ui.write(_('performing an upgrade with "--run" will make the following '
+                   'changes:\n\n'))
+
+        printrequirements()
+        printupgradeactions()
+
+        unusedoptimize = [i for i in improvements
+                          if i.name not in actions and i.type == optimisation]
+        if unusedoptimize:
+            ui.write(_('additional optimizations are available by specifying '
+                     '"--optimize <name>":\n\n'))
+            for i in unusedoptimize:
+                ui.write(_('%s\n   %s\n\n') % (i.name, i.description))
+        return
+
+    # Else we're in the run=true case.
+    ui.write(_('upgrade will perform the following actions:\n\n'))
+    printrequirements()
+    printupgradeactions()
+
+    ui.write(_('beginning upgrade...\n'))
+    with repo.wlock():
+        with repo.lock():
+            ui.write(_('repository locked and read-only\n'))
+            # Our strategy for upgrading the repository is to create a new,
+            # temporary repository, write data to it, then do a swap of the
+            # data. There are less heavyweight ways to do this, but it is easier
+            # to create a new repo object than to instantiate all the components
+            # (like the store) separately.
+            tmppath = tempfile.mkdtemp(prefix='upgrade.', dir=repo.path)
+            backuppath = None
+            try:
+                ui.write(_('creating temporary repository to stage migrated '
+                           'data: %s\n') % tmppath)
+                dstrepo = localrepo.localrepository(repo.baseui,
+                                                    path=tmppath,
+                                                    create=True)
+
+                with dstrepo.wlock():
+                    with dstrepo.lock():
+                        backuppath = _upgraderepo(ui, repo, dstrepo, newreqs,
+                                                  actions)
+
+            finally:
+                ui.write(_('removing temporary repository %s\n') % tmppath)
+                repo.vfs.rmtree(tmppath, forcibly=True)
+
+                if backuppath:
+                    ui.warn(_('copy of old repository backed up at %s\n') %
+                            backuppath)
+                    ui.warn(_('the old repository will not be deleted; remove '
+                              'it to free up disk space once the upgraded '
+                              'repository is verified\n'))