repair: use context manager for lock management

If repo.lock() raised inside of the try block, 'tr' would have been None in the
finally block where it tries to release().  Modernize the syntax instead of just
winching the lock out of the try block.

I found several other instances of acquiring the lock inside of the 'try', but
those finally blocks handle None references.  I also started switching some
trivial try/finally blocks to context managers, but didn't get them all because
indenting over 3x for lock, wlock and transaction would have spilled over 80
characters.  That got me wondering if there should be a repo.rwlock(), to handle
locking and unlocking in the proper order.

It also looks like py27 supports supports multiple context managers for a single
'with' statement.  Should I hold off on the rest until py26 is dropped?

mercurial/repair.py

@@ -1,1102 +1,1097 b''
 # repair.py - functions for repository repair for mercurial
 #
 # Copyright 2005, 2006 Chris Mason <[e-mail]>
 # 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 errno
 import hashlib
 import stat
 import tempfile
 
 from .i18n import _
 from .node import short
 from . import (
     bundle2,
     changegroup,
     changelog,
     error,
     exchange,
     manifest,
     obsolete,
     revlog,
     scmutil,
     util,
     vfs as vfsmod,
 )
 
 def _bundle(repo, bases, heads, node, suffix, compress=True):
     """create a bundle with the specified revisions as a backup"""
     cgversion = changegroup.safeversion(repo)
 
     cg = changegroup.changegroupsubset(repo, bases, heads, 'strip',
                                        version=cgversion)
     backupdir = "strip-backup"
     vfs = repo.vfs
     if not vfs.isdir(backupdir):
         vfs.mkdir(backupdir)
 
     # Include a hash of all the nodes in the filename for uniqueness
     allcommits = repo.set('%ln::%ln', bases, heads)
     allhashes = sorted(c.hex() for c in allcommits)
     totalhash = hashlib.sha1(''.join(allhashes)).hexdigest()
     name = "%s/%s-%s-%s.hg" % (backupdir, short(node), totalhash[:8], suffix)
 
     comp = None
     if cgversion != '01':
         bundletype = "HG20"
         if compress:
             comp = 'BZ'
     elif compress:
         bundletype = "HG10BZ"
     else:
         bundletype = "HG10UN"
     return bundle2.writebundle(repo.ui, cg, name, bundletype, vfs,
                                    compression=comp)
 
 def _collectfiles(repo, striprev):
     """find out the filelogs affected by the strip"""
     files = set()
 
     for x in xrange(striprev, len(repo)):
         files.update(repo[x].files())
 
     return sorted(files)
 
 def _collectbrokencsets(repo, files, striprev):
     """return the changesets which will be broken by the truncation"""
     s = set()
     def collectone(revlog):
         _, brokenset = revlog.getstrippoint(striprev)
         s.update([revlog.linkrev(r) for r in brokenset])
 
     collectone(repo.manifestlog._revlog)
     for fname in files:
         collectone(repo.file(fname))
 
     return s
 
 def strip(ui, repo, nodelist, backup=True, topic='backup'):
     # This function operates within a transaction of its own, but does
     # not take any lock on the repo.
     # Simple way to maintain backwards compatibility for this
     # argument.
     if backup in ['none', 'strip']:
         backup = False
 
     repo = repo.unfiltered()
     repo.destroying()
 
     cl = repo.changelog
     # TODO handle undo of merge sets
     if isinstance(nodelist, str):
         nodelist = [nodelist]
     striplist = [cl.rev(node) for node in nodelist]
     striprev = min(striplist)
 
     files = _collectfiles(repo, striprev)
     saverevs = _collectbrokencsets(repo, files, striprev)
 
     # Some revisions with rev > striprev may not be descendants of striprev.
     # We have to find these revisions and put them in a bundle, so that
     # we can restore them after the truncations.
     # To create the bundle we use repo.changegroupsubset which requires
     # the list of heads and bases of the set of interesting revisions.
     # (head = revision in the set that has no descendant in the set;
     #  base = revision in the set that has no ancestor in the set)
     tostrip = set(striplist)
     saveheads = set(saverevs)
     for r in cl.revs(start=striprev + 1):
         if any(p in tostrip for p in cl.parentrevs(r)):
             tostrip.add(r)
 
         if r not in tostrip:
             saverevs.add(r)
             saveheads.difference_update(cl.parentrevs(r))
             saveheads.add(r)
     saveheads = [cl.node(r) for r in saveheads]
 
     # compute base nodes
     if saverevs:
         descendants = set(cl.descendants(saverevs))
         saverevs.difference_update(descendants)
     savebases = [cl.node(r) for r in saverevs]
     stripbases = [cl.node(r) for r in tostrip]
 
     # For a set s, max(parents(s) - s) is the same as max(heads(::s - s)), but
     # is much faster
     newbmtarget = repo.revs('max(parents(%ld) - (%ld))', tostrip, tostrip)
     if newbmtarget:
         newbmtarget = repo[newbmtarget.first()].node()
     else:
         newbmtarget = '.'
 
     bm = repo._bookmarks
     updatebm = []
     for m in bm:
         rev = repo[bm[m]].rev()
         if rev in tostrip:
             updatebm.append(m)
 
     # create a changegroup for all the branches we need to keep
     backupfile = None
     vfs = repo.vfs
     node = nodelist[-1]
     if backup:
         backupfile = _bundle(repo, stripbases, cl.heads(), node, topic)
         repo.ui.status(_("saved backup bundle to %s\n") %
                        vfs.join(backupfile))
         repo.ui.log("backupbundle", "saved backup bundle to %s\n",
                     vfs.join(backupfile))
     tmpbundlefile = None
     if saveheads:
         # do not compress temporary bundle if we remove it from disk later
         tmpbundlefile = _bundle(repo, savebases, saveheads, node, 'temp',
                             compress=False)
 
     mfst = repo.manifestlog._revlog
 
     curtr = repo.currenttransaction()
     if curtr is not None:
         del curtr  # avoid carrying reference to transaction for nothing
         msg = _('programming error: cannot strip from inside a transaction')
         raise error.Abort(msg, hint=_('contact your extension maintainer'))
 
     try:
         with repo.transaction("strip") as tr:
             offset = len(tr.entries)
 
             tr.startgroup()
             cl.strip(striprev, tr)
             mfst.strip(striprev, tr)
             if 'treemanifest' in repo.requirements: # safe but unnecessary
                                                     # otherwise
                 for unencoded, encoded, size in repo.store.datafiles():
                     if (unencoded.startswith('meta/') and
                         unencoded.endswith('00manifest.i')):
                         dir = unencoded[5:-12]
                         repo.manifestlog._revlog.dirlog(dir).strip(striprev, tr)
             for fn in files:
                 repo.file(fn).strip(striprev, tr)
             tr.endgroup()
 
             for i in xrange(offset, len(tr.entries)):
                 file, troffset, ignore = tr.entries[i]
                 with repo.svfs(file, 'a', checkambig=True) as fp:
                     fp.truncate(troffset)
                 if troffset == 0:
                     repo.store.markremoved(file)
 
         if tmpbundlefile:
             ui.note(_("adding branch\n"))
             f = vfs.open(tmpbundlefile, "rb")
             gen = exchange.readbundle(ui, f, tmpbundlefile, vfs)
             if not repo.ui.verbose:
                 # silence internal shuffling chatter
                 repo.ui.pushbuffer()
             if isinstance(gen, bundle2.unbundle20):
                 with repo.transaction('strip') as tr:
                     tr.hookargs = {'source': 'strip',
                                    'url': 'bundle:' + vfs.join(tmpbundlefile)}
                     bundle2.applybundle(repo, gen, tr, source='strip',
                                         url='bundle:' + vfs.join(tmpbundlefile))
             else:
                 gen.apply(repo, 'strip', 'bundle:' + vfs.join(tmpbundlefile),
                           True)
             if not repo.ui.verbose:
                 repo.ui.popbuffer()
             f.close()
         repo._phasecache.invalidate()
 
         for m in updatebm:
             bm[m] = repo[newbmtarget].node()
-        lock = tr = None
-        try:
-            lock = repo.lock()
-            tr = repo.transaction('repair')
-            bm.recordchange(tr)
-            tr.close()
-        finally:
-            tr.release()
-            lock.release()
+
+        with repo.lock():
+            with repo.transaction('repair') as tr:
+                bm.recordchange(tr)
 
         # remove undo files
         for undovfs, undofile in repo.undofiles():
             try:
                 undovfs.unlink(undofile)
             except OSError as e:
                 if e.errno != errno.ENOENT:
                     ui.warn(_('error removing %s: %s\n') %
                             (undovfs.join(undofile), str(e)))
 
     except: # re-raises
         if backupfile:
             ui.warn(_("strip failed, backup bundle stored in '%s'\n")
                     % vfs.join(backupfile))
         if tmpbundlefile:
             ui.warn(_("strip failed, unrecovered changes stored in '%s'\n")
                     % vfs.join(tmpbundlefile))
             ui.warn(_("(fix the problem, then recover the changesets with "
                       "\"hg unbundle '%s'\")\n") % vfs.join(tmpbundlefile))
         raise
     else:
         if tmpbundlefile:
             # Remove temporary bundle only if there were no exceptions
             vfs.unlink(tmpbundlefile)
 
     repo.destroyed()
     # return the backup file path (or None if 'backup' was False) so
     # extensions can use it
     return backupfile
 
 def rebuildfncache(ui, repo):
     """Rebuilds the fncache file from repo history.
 
     Missing entries will be added. Extra entries will be removed.
     """
     repo = repo.unfiltered()
 
     if 'fncache' not in repo.requirements:
         ui.warn(_('(not rebuilding fncache because repository does not '
                   'support fncache)\n'))
         return
 
     with repo.lock():
         fnc = repo.store.fncache
         # Trigger load of fncache.
         if 'irrelevant' in fnc:
             pass
 
         oldentries = set(fnc.entries)
         newentries = set()
         seenfiles = set()
 
         repolen = len(repo)
         for rev in repo:
             ui.progress(_('rebuilding'), rev, total=repolen,
                         unit=_('changesets'))
 
             ctx = repo[rev]
             for f in ctx.files():
                 # This is to minimize I/O.
                 if f in seenfiles:
                     continue
                 seenfiles.add(f)
 
                 i = 'data/%s.i' % f
                 d = 'data/%s.d' % f
 
                 if repo.store._exists(i):
                     newentries.add(i)
                 if repo.store._exists(d):
                     newentries.add(d)
 
         ui.progress(_('rebuilding'), None)
 
         if 'treemanifest' in repo.requirements: # safe but unnecessary otherwise
             for dir in util.dirs(seenfiles):
                 i = 'meta/%s/00manifest.i' % dir
                 d = 'meta/%s/00manifest.d' % dir
 
                 if repo.store._exists(i):
                     newentries.add(i)
                 if repo.store._exists(d):
                     newentries.add(d)
 
         addcount = len(newentries - oldentries)
         removecount = len(oldentries - newentries)
         for p in sorted(oldentries - newentries):
             ui.write(_('removing %s\n') % p)
         for p in sorted(newentries - oldentries):
             ui.write(_('adding %s\n') % p)
 
         if addcount or removecount:
             ui.write(_('%d items added, %d removed from fncache\n') %
                      (addcount, removecount))
             fnc.entries = newentries
             fnc._dirty = True
 
             with repo.transaction('fncache') as tr:
                 fnc.write(tr)
         else:
             ui.write(_('fncache already up to date\n'))
 
 def stripbmrevset(repo, mark):
     """
     The revset to strip when strip is called with -B mark
 
     Needs to live here so extensions can use it and wrap it even when strip is
     not enabled or not present on a box.
     """
     return repo.revs("ancestors(bookmark(%s)) - "
                      "ancestors(head() and not bookmark(%s)) - "
                      "ancestors(bookmark() and not bookmark(%s))",
                      mark, mark, mark)
 
 def deleteobsmarkers(obsstore, indices):
     """Delete some obsmarkers from obsstore and return how many were deleted
 
     'indices' is a list of ints which are the indices
     of the markers to be deleted.
 
     Every invocation of this function completely rewrites the obsstore file,
     skipping the markers we want to be removed. The new temporary file is
     created, remaining markers are written there and on .close() this file
     gets atomically renamed to obsstore, thus guaranteeing consistency."""
     if not indices:
         # we don't want to rewrite the obsstore with the same content
         return
 
     left = []
     current = obsstore._all
     n = 0
     for i, m in enumerate(current):
         if i in indices:
             n += 1
             continue
         left.append(m)
 
     newobsstorefile = obsstore.svfs('obsstore', 'w', atomictemp=True)
     for bytes in obsolete.encodemarkers(left, True, obsstore._version):
         newobsstorefile.write(bytes)
     newobsstorefile.close()
     return n
 
 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'))