rust: module policy with importrust

We introduce two rust+c module policies and a new
`policy.importrust()` that makes use of them.

This simple approach provides runtime switching of
implementations, which is crucial for the performance
measurements such as those Octobus does with ASV.

It can also be useful for bug analysis.

It also has the advantage of making conditionals in
Rust callers more uniform, in particular
abstracting over specifics like `demandimport`

At this point, the build stays unchanged, with the rust-cpython based
`rustext` module being built if HGWITHRUSTEXT=cpython.

More transparency for the callers, i.e., just using
`policy.importmod` would be a much longer term and riskier
effort for the following reasons:

1. It would require to define common module boundaries
   for the three or four cases (pure, c, rust+ext, cffi) and that
   is premature with the Rust extension currently under heavy
   development in areas that are outside the scope of the C extensions.
2. It would imply internal API changes that are not currently wished,
   as the case of ancestors demonstrates.
3. The lack of data or property-like attributes (tp_member
   and tp_getset) in current `rust-cpython` makes it impossible to
   achieve direct transparent replacement of pure Python classes by
   Rust extension code, meaning that the caller sometimes has to be able
   to make adjustments or provide additional wrapping.

mercurial/debugcommands.py

@@ -1,3469 +1,3481 b''
 # debugcommands.py - command processing for debug* commands
 #
 # Copyright 2005-2016 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import codecs
 import collections
 import difflib
 import errno
 import operator
 import os
 import random
 import re
 import socket
 import ssl
 import stat
 import string
 import subprocess
 import sys
 import time
 
 from .i18n import _
 from .node import (
     bin,
     hex,
     nullhex,
     nullid,
     nullrev,
     short,
 )
 from . import (
     bundle2,
     changegroup,
     cmdutil,
     color,
     context,
     copies,
     dagparser,
     encoding,
     error,
     exchange,
     extensions,
     filemerge,
     filesetlang,
     formatter,
     hg,
     httppeer,
     localrepo,
     lock as lockmod,
     logcmdutil,
     merge as mergemod,
     obsolete,
     obsutil,
     phases,
     policy,
     pvec,
     pycompat,
     registrar,
     repair,
     revlog,
     revset,
     revsetlang,
     scmutil,
     setdiscovery,
     simplemerge,
     sshpeer,
     sslutil,
     streamclone,
     templater,
     treediscovery,
     upgrade,
     url as urlmod,
     util,
     vfs as vfsmod,
     wireprotoframing,
     wireprotoserver,
     wireprotov2peer,
 )
 from .utils import (
     cborutil,
     compression,
     dateutil,
     procutil,
     stringutil,
 )
 
 from .revlogutils import (
     deltas as deltautil
 )
 
 release = lockmod.release
 
 command = registrar.command()
 
 @command('debugancestor', [], _('[INDEX] REV1 REV2'), optionalrepo=True)
 def debugancestor(ui, repo, *args):
     """find the ancestor revision of two revisions in a given index"""
     if len(args) == 3:
         index, rev1, rev2 = args
         r = revlog.revlog(vfsmod.vfs(encoding.getcwd(), audit=False), index)
         lookup = r.lookup
     elif len(args) == 2:
         if not repo:
             raise error.Abort(_('there is no Mercurial repository here '
                                 '(.hg not found)'))
         rev1, rev2 = args
         r = repo.changelog
         lookup = repo.lookup
     else:
         raise error.Abort(_('either two or three arguments required'))
     a = r.ancestor(lookup(rev1), lookup(rev2))
     ui.write('%d:%s\n' % (r.rev(a), hex(a)))
 
 @command('debugapplystreamclonebundle', [], 'FILE')
 def debugapplystreamclonebundle(ui, repo, fname):
     """apply a stream clone bundle file"""
     f = hg.openpath(ui, fname)
     gen = exchange.readbundle(ui, f, fname)
     gen.apply(repo)
 
 @command('debugbuilddag',
     [('m', 'mergeable-file', None, _('add single file mergeable changes')),
     ('o', 'overwritten-file', None, _('add single file all revs overwrite')),
     ('n', 'new-file', None, _('add new file at each rev'))],
     _('[OPTION]... [TEXT]'))
 def debugbuilddag(ui, repo, text=None,
                   mergeable_file=False,
                   overwritten_file=False,
                   new_file=False):
     """builds a repo with a given DAG from scratch in the current empty repo
 
     The description of the DAG is read from stdin if not given on the
     command line.
 
     Elements:
 
      - "+n" is a linear run of n nodes based on the current default parent
      - "." is a single node based on the current default parent
      - "$" resets the default parent to null (implied at the start);
            otherwise the default parent is always the last node created
      - "<p" sets the default parent to the backref p
      - "*p" is a fork at parent p, which is a backref
      - "*p1/p2" is a merge of parents p1 and p2, which are backrefs
      - "/p2" is a merge of the preceding node and p2
      - ":tag" defines a local tag for the preceding node
      - "@branch" sets the named branch for subsequent nodes
      - "#...\\n" is a comment up to the end of the line
 
     Whitespace between the above elements is ignored.
 
     A backref is either
 
      - a number n, which references the node curr-n, where curr is the current
        node, or
      - the name of a local tag you placed earlier using ":tag", or
      - empty to denote the default parent.
 
     All string valued-elements are either strictly alphanumeric, or must
     be enclosed in double quotes ("..."), with "\\" as escape character.
     """
 
     if text is None:
         ui.status(_("reading DAG from stdin\n"))
         text = ui.fin.read()
 
     cl = repo.changelog
     if len(cl) > 0:
         raise error.Abort(_('repository is not empty'))
 
     # determine number of revs in DAG
     total = 0
     for type, data in dagparser.parsedag(text):
         if type == 'n':
             total += 1
 
     if mergeable_file:
         linesperrev = 2
         # make a file with k lines per rev
         initialmergedlines = ['%d' % i
                               for i in pycompat.xrange(0, total * linesperrev)]
         initialmergedlines.append("")
 
     tags = []
     progress = ui.makeprogress(_('building'), unit=_('revisions'),
                                total=total)
     with progress, repo.wlock(), repo.lock(), repo.transaction("builddag"):
         at = -1
         atbranch = 'default'
         nodeids = []
         id = 0
         progress.update(id)
         for type, data in dagparser.parsedag(text):
             if type == 'n':
                 ui.note(('node %s\n' % pycompat.bytestr(data)))
                 id, ps = data
 
                 files = []
                 filecontent = {}
 
                 p2 = None
                 if mergeable_file:
                     fn = "mf"
                     p1 = repo[ps[0]]
                     if len(ps) > 1:
                         p2 = repo[ps[1]]
                         pa = p1.ancestor(p2)
                         base, local, other = [x[fn].data() for x in (pa, p1,
                                                                      p2)]
                         m3 = simplemerge.Merge3Text(base, local, other)
                         ml = [l.strip() for l in m3.merge_lines()]
                         ml.append("")
                     elif at > 0:
                         ml = p1[fn].data().split("\n")
                     else:
                         ml = initialmergedlines
                     ml[id * linesperrev] += " r%i" % id
                     mergedtext = "\n".join(ml)
                     files.append(fn)
                     filecontent[fn] = mergedtext
 
                 if overwritten_file:
                     fn = "of"
                     files.append(fn)
                     filecontent[fn] = "r%i\n" % id
 
                 if new_file:
                     fn = "nf%i" % id
                     files.append(fn)
                     filecontent[fn] = "r%i\n" % id
                     if len(ps) > 1:
                         if not p2:
                             p2 = repo[ps[1]]
                         for fn in p2:
                             if fn.startswith("nf"):
                                 files.append(fn)
                                 filecontent[fn] = p2[fn].data()
 
                 def fctxfn(repo, cx, path):
                     if path in filecontent:
                         return context.memfilectx(repo, cx, path,
                                                   filecontent[path])
                     return None
 
                 if len(ps) == 0 or ps[0] < 0:
                     pars = [None, None]
                 elif len(ps) == 1:
                     pars = [nodeids[ps[0]], None]
                 else:
                     pars = [nodeids[p] for p in ps]
                 cx = context.memctx(repo, pars, "r%i" % id, files, fctxfn,
                                     date=(id, 0),
                                     user="debugbuilddag",
                                     extra={'branch': atbranch})
                 nodeid = repo.commitctx(cx)
                 nodeids.append(nodeid)
                 at = id
             elif type == 'l':
                 id, name = data
                 ui.note(('tag %s\n' % name))
                 tags.append("%s %s\n" % (hex(repo.changelog.node(id)), name))
             elif type == 'a':
                 ui.note(('branch %s\n' % data))
                 atbranch = data
             progress.update(id)
 
         if tags:
             repo.vfs.write("localtags", "".join(tags))
 
 def _debugchangegroup(ui, gen, all=None, indent=0, **opts):
     indent_string = ' ' * indent
     if all:
         ui.write(("%sformat: id, p1, p2, cset, delta base, len(delta)\n")
                  % indent_string)
 
         def showchunks(named):
             ui.write("\n%s%s\n" % (indent_string, named))
             for deltadata in gen.deltaiter():
                 node, p1, p2, cs, deltabase, delta, flags = deltadata
                 ui.write("%s%s %s %s %s %s %d\n" %
                          (indent_string, hex(node), hex(p1), hex(p2),
                           hex(cs), hex(deltabase), len(delta)))
 
         chunkdata = gen.changelogheader()
         showchunks("changelog")
         chunkdata = gen.manifestheader()
         showchunks("manifest")
         for chunkdata in iter(gen.filelogheader, {}):
             fname = chunkdata['filename']
             showchunks(fname)
     else:
         if isinstance(gen, bundle2.unbundle20):
             raise error.Abort(_('use debugbundle2 for this file'))
         chunkdata = gen.changelogheader()
         for deltadata in gen.deltaiter():
             node, p1, p2, cs, deltabase, delta, flags = deltadata
             ui.write("%s%s\n" % (indent_string, hex(node)))
 
 def _debugobsmarkers(ui, part, indent=0, **opts):
     """display version and markers contained in 'data'"""
     opts = pycompat.byteskwargs(opts)
     data = part.read()
     indent_string = ' ' * indent
     try:
         version, markers = obsolete._readmarkers(data)
     except error.UnknownVersion as exc:
         msg = "%sunsupported version: %s (%d bytes)\n"
         msg %= indent_string, exc.version, len(data)
         ui.write(msg)
     else:
         msg = "%sversion: %d (%d bytes)\n"
         msg %= indent_string, version, len(data)
         ui.write(msg)
         fm = ui.formatter('debugobsolete', opts)
         for rawmarker in sorted(markers):
             m = obsutil.marker(None, rawmarker)
             fm.startitem()
             fm.plain(indent_string)
             cmdutil.showmarker(fm, m)
         fm.end()
 
 def _debugphaseheads(ui, data, indent=0):
     """display version and markers contained in 'data'"""
     indent_string = ' ' * indent
     headsbyphase = phases.binarydecode(data)
     for phase in phases.allphases:
         for head in headsbyphase[phase]:
             ui.write(indent_string)
             ui.write('%s %s\n' % (hex(head), phases.phasenames[phase]))
 
 def _quasirepr(thing):
     if isinstance(thing, (dict, util.sortdict, collections.OrderedDict)):
         return '{%s}' % (
             b', '.join(b'%s: %s' % (k, thing[k]) for k in sorted(thing)))
     return pycompat.bytestr(repr(thing))
 
 def _debugbundle2(ui, gen, all=None, **opts):
     """lists the contents of a bundle2"""
     if not isinstance(gen, bundle2.unbundle20):
         raise error.Abort(_('not a bundle2 file'))
     ui.write(('Stream params: %s\n' % _quasirepr(gen.params)))
     parttypes = opts.get(r'part_type', [])
     for part in gen.iterparts():
         if parttypes and part.type not in parttypes:
             continue
         msg = '%s -- %s (mandatory: %r)\n'
         ui.write((msg % (part.type, _quasirepr(part.params), part.mandatory)))
         if part.type == 'changegroup':
             version = part.params.get('version', '01')
             cg = changegroup.getunbundler(version, part, 'UN')
             if not ui.quiet:
                 _debugchangegroup(ui, cg, all=all, indent=4, **opts)
         if part.type == 'obsmarkers':
             if not ui.quiet:
                 _debugobsmarkers(ui, part, indent=4, **opts)
         if part.type == 'phase-heads':
             if not ui.quiet:
                 _debugphaseheads(ui, part, indent=4)
 
 @command('debugbundle',
         [('a', 'all', None, _('show all details')),
          ('', 'part-type', [], _('show only the named part type')),
          ('', 'spec', None, _('print the bundlespec of the bundle'))],
         _('FILE'),
         norepo=True)
 def debugbundle(ui, bundlepath, all=None, spec=None, **opts):
     """lists the contents of a bundle"""
     with hg.openpath(ui, bundlepath) as f:
         if spec:
             spec = exchange.getbundlespec(ui, f)
             ui.write('%s\n' % spec)
             return
 
         gen = exchange.readbundle(ui, f, bundlepath)
         if isinstance(gen, bundle2.unbundle20):
             return _debugbundle2(ui, gen, all=all, **opts)
         _debugchangegroup(ui, gen, all=all, **opts)
 
 @command('debugcapabilities',
         [], _('PATH'),
         norepo=True)
 def debugcapabilities(ui, path, **opts):
     """lists the capabilities of a remote peer"""
     opts = pycompat.byteskwargs(opts)
     peer = hg.peer(ui, opts, path)
     caps = peer.capabilities()
     ui.write(('Main capabilities:\n'))
     for c in sorted(caps):
         ui.write(('  %s\n') % c)
     b2caps = bundle2.bundle2caps(peer)
     if b2caps:
         ui.write(('Bundle2 capabilities:\n'))
         for key, values in sorted(b2caps.iteritems()):
             ui.write(('  %s\n') % key)
             for v in values:
                 ui.write(('    %s\n') % v)
 
 @command('debugcheckstate', [], '')
 def debugcheckstate(ui, repo):
     """validate the correctness of the current dirstate"""
     parent1, parent2 = repo.dirstate.parents()
     m1 = repo[parent1].manifest()
     m2 = repo[parent2].manifest()
     errors = 0
     for f in repo.dirstate:
         state = repo.dirstate[f]
         if state in "nr" and f not in m1:
             ui.warn(_("%s in state %s, but not in manifest1\n") % (f, state))
             errors += 1
         if state in "a" and f in m1:
             ui.warn(_("%s in state %s, but also in manifest1\n") % (f, state))
             errors += 1
         if state in "m" and f not in m1 and f not in m2:
             ui.warn(_("%s in state %s, but not in either manifest\n") %
                     (f, state))
             errors += 1
     for f in m1:
         state = repo.dirstate[f]
         if state not in "nrm":
             ui.warn(_("%s in manifest1, but listed as state %s") % (f, state))
             errors += 1
     if errors:
         error = _(".hg/dirstate inconsistent with current parent's manifest")
         raise error.Abort(error)
 
 @command('debugcolor',
         [('', 'style', None, _('show all configured styles'))],
         'hg debugcolor')
 def debugcolor(ui, repo, **opts):
     """show available color, effects or style"""
     ui.write(('color mode: %s\n') % stringutil.pprint(ui._colormode))
     if opts.get(r'style'):
         return _debugdisplaystyle(ui)
     else:
         return _debugdisplaycolor(ui)
 
 def _debugdisplaycolor(ui):
     ui = ui.copy()
     ui._styles.clear()
     for effect in color._activeeffects(ui).keys():
         ui._styles[effect] = effect
     if ui._terminfoparams:
         for k, v in ui.configitems('color'):
             if k.startswith('color.'):
                 ui._styles[k] = k[6:]
             elif k.startswith('terminfo.'):
                 ui._styles[k] = k[9:]
     ui.write(_('available colors:\n'))
     # sort label with a '_' after the other to group '_background' entry.
     items = sorted(ui._styles.items(),
                    key=lambda i: ('_' in i[0], i[0], i[1]))
     for colorname, label in items:
         ui.write(('%s\n') % colorname, label=label)
 
 def _debugdisplaystyle(ui):
     ui.write(_('available style:\n'))
     if not ui._styles:
         return
     width = max(len(s) for s in ui._styles)
     for label, effects in sorted(ui._styles.items()):
         ui.write('%s' % label, label=label)
         if effects:
             # 50
             ui.write(': ')
             ui.write(' ' * (max(0, width - len(label))))
             ui.write(', '.join(ui.label(e, e) for e in effects.split()))
         ui.write('\n')
 
 @command('debugcreatestreamclonebundle', [], 'FILE')
 def debugcreatestreamclonebundle(ui, repo, fname):
     """create a stream clone bundle file
 
     Stream bundles are special bundles that are essentially archives of
     revlog files. They are commonly used for cloning very quickly.
     """
     # TODO we may want to turn this into an abort when this functionality
     # is moved into `hg bundle`.
     if phases.hassecret(repo):
         ui.warn(_('(warning: stream clone bundle will contain secret '
                   'revisions)\n'))
 
     requirements, gen = streamclone.generatebundlev1(repo)
     changegroup.writechunks(ui, gen, fname)
 
     ui.write(_('bundle requirements: %s\n') % ', '.join(sorted(requirements)))
 
 @command('debugdag',
     [('t', 'tags', None, _('use tags as labels')),
     ('b', 'branches', None, _('annotate with branch names')),
     ('', 'dots', None, _('use dots for runs')),
     ('s', 'spaces', None, _('separate elements by spaces'))],
     _('[OPTION]... [FILE [REV]...]'),
     optionalrepo=True)
 def debugdag(ui, repo, file_=None, *revs, **opts):
     """format the changelog or an index DAG as a concise textual description
 
     If you pass a revlog index, the revlog's DAG is emitted. If you list
     revision numbers, they get labeled in the output as rN.
 
     Otherwise, the changelog DAG of the current repo is emitted.
     """
     spaces = opts.get(r'spaces')
     dots = opts.get(r'dots')
     if file_:
         rlog = revlog.revlog(vfsmod.vfs(encoding.getcwd(), audit=False),
                              file_)
         revs = set((int(r) for r in revs))
         def events():
             for r in rlog:
                 yield 'n', (r, list(p for p in rlog.parentrevs(r)
                                         if p != -1))
                 if r in revs:
                     yield 'l', (r, "r%i" % r)
     elif repo:
         cl = repo.changelog
         tags = opts.get(r'tags')
         branches = opts.get(r'branches')
         if tags:
             labels = {}
             for l, n in repo.tags().items():
                 labels.setdefault(cl.rev(n), []).append(l)
         def events():
             b = "default"
             for r in cl:
                 if branches:
                     newb = cl.read(cl.node(r))[5]['branch']
                     if newb != b:
                         yield 'a', newb
                         b = newb
                 yield 'n', (r, list(p for p in cl.parentrevs(r)
                                         if p != -1))
                 if tags:
                     ls = labels.get(r)
                     if ls:
                         for l in ls:
                             yield 'l', (r, l)
     else:
         raise error.Abort(_('need repo for changelog dag'))
 
     for line in dagparser.dagtextlines(events(),
                                        addspaces=spaces,
                                        wraplabels=True,
                                        wrapannotations=True,
                                        wrapnonlinear=dots,
                                        usedots=dots,
                                        maxlinewidth=70):
         ui.write(line)
         ui.write("\n")
 
 @command('debugdata', cmdutil.debugrevlogopts, _('-c|-m|FILE REV'))
 def debugdata(ui, repo, file_, rev=None, **opts):
     """dump the contents of a data file revision"""
     opts = pycompat.byteskwargs(opts)
     if opts.get('changelog') or opts.get('manifest') or opts.get('dir'):
         if rev is not None:
             raise error.CommandError('debugdata', _('invalid arguments'))
         file_, rev = None, file_
     elif rev is None:
         raise error.CommandError('debugdata', _('invalid arguments'))
     r = cmdutil.openstorage(repo, 'debugdata', file_, opts)
     try:
         ui.write(r.revision(r.lookup(rev), raw=True))
     except KeyError:
         raise error.Abort(_('invalid revision identifier %s') % rev)
 
 @command('debugdate',
     [('e', 'extended', None, _('try extended date formats'))],
     _('[-e] DATE [RANGE]'),
     norepo=True, optionalrepo=True)
 def debugdate(ui, date, range=None, **opts):
     """parse and display a date"""
     if opts[r"extended"]:
         d = dateutil.parsedate(date, util.extendeddateformats)
     else:
         d = dateutil.parsedate(date)
     ui.write(("internal: %d %d\n") % d)
     ui.write(("standard: %s\n") % dateutil.datestr(d))
     if range:
         m = dateutil.matchdate(range)
         ui.write(("match: %s\n") % m(d[0]))
 
 @command('debugdeltachain',
     cmdutil.debugrevlogopts + cmdutil.formatteropts,
     _('-c|-m|FILE'),
     optionalrepo=True)
 def debugdeltachain(ui, repo, file_=None, **opts):
     """dump information about delta chains in a revlog
 
     Output can be templatized. Available template keywords are:
 
     :``rev``:       revision number
     :``chainid``:   delta chain identifier (numbered by unique base)
     :``chainlen``:  delta chain length to this revision
     :``prevrev``:   previous revision in delta chain
     :``deltatype``: role of delta / how it was computed
     :``compsize``:  compressed size of revision
     :``uncompsize``: uncompressed size of revision
     :``chainsize``: total size of compressed revisions in chain
     :``chainratio``: total chain size divided by uncompressed revision size
                     (new delta chains typically start at ratio 2.00)
     :``lindist``:   linear distance from base revision in delta chain to end
                     of this revision
     :``extradist``: total size of revisions not part of this delta chain from
                     base of delta chain to end of this revision; a measurement
                     of how much extra data we need to read/seek across to read
                     the delta chain for this revision
     :``extraratio``: extradist divided by chainsize; another representation of
                     how much unrelated data is needed to load this delta chain
 
     If the repository is configured to use the sparse read, additional keywords
     are available:
 
     :``readsize``:     total size of data read from the disk for a revision
                        (sum of the sizes of all the blocks)
     :``largestblock``: size of the largest block of data read from the disk
     :``readdensity``:  density of useful bytes in the data read from the disk
     :``srchunks``:  in how many data hunks the whole revision would be read
 
     The sparse read can be enabled with experimental.sparse-read = True
     """
     opts = pycompat.byteskwargs(opts)
     r = cmdutil.openrevlog(repo, 'debugdeltachain', file_, opts)
     index = r.index
     start = r.start
     length = r.length
     generaldelta = r.version & revlog.FLAG_GENERALDELTA
     withsparseread = getattr(r, '_withsparseread', False)
 
     def revinfo(rev):
         e = index[rev]
         compsize = e[1]
         uncompsize = e[2]
         chainsize = 0
 
         if generaldelta:
             if e[3] == e[5]:
                 deltatype = 'p1'
             elif e[3] == e[6]:
                 deltatype = 'p2'
             elif e[3] == rev - 1:
                 deltatype = 'prev'
             elif e[3] == rev:
                 deltatype = 'base'
             else:
                 deltatype = 'other'
         else:
             if e[3] == rev:
                 deltatype = 'base'
             else:
                 deltatype = 'prev'
 
         chain = r._deltachain(rev)[0]
         for iterrev in chain:
             e = index[iterrev]
             chainsize += e[1]
 
         return compsize, uncompsize, deltatype, chain, chainsize
 
     fm = ui.formatter('debugdeltachain', opts)
 
     fm.plain('    rev  chain# chainlen     prev   delta       '
              'size    rawsize  chainsize     ratio   lindist extradist '
              'extraratio')
     if withsparseread:
         fm.plain('   readsize largestblk rddensity srchunks')
     fm.plain('\n')
 
     chainbases = {}
     for rev in r:
         comp, uncomp, deltatype, chain, chainsize = revinfo(rev)
         chainbase = chain[0]
         chainid = chainbases.setdefault(chainbase, len(chainbases) + 1)
         basestart = start(chainbase)
         revstart = start(rev)
         lineardist = revstart + comp - basestart
         extradist = lineardist - chainsize
         try:
             prevrev = chain[-2]
         except IndexError:
             prevrev = -1
 
         if uncomp != 0:
             chainratio = float(chainsize) / float(uncomp)
         else:
             chainratio = chainsize
 
         if chainsize != 0:
             extraratio = float(extradist) / float(chainsize)
         else:
             extraratio = extradist
 
         fm.startitem()
         fm.write('rev chainid chainlen prevrev deltatype compsize '
                  'uncompsize chainsize chainratio lindist extradist '
                  'extraratio',
                  '%7d %7d %8d %8d %7s %10d %10d %10d %9.5f %9d %9d %10.5f',
                  rev, chainid, len(chain), prevrev, deltatype, comp,
                  uncomp, chainsize, chainratio, lineardist, extradist,
                  extraratio,
                  rev=rev, chainid=chainid, chainlen=len(chain),
                  prevrev=prevrev, deltatype=deltatype, compsize=comp,
                  uncompsize=uncomp, chainsize=chainsize,
                  chainratio=chainratio, lindist=lineardist,
                  extradist=extradist, extraratio=extraratio)
         if withsparseread:
             readsize = 0
             largestblock = 0
             srchunks = 0
 
             for revschunk in deltautil.slicechunk(r, chain):
                 srchunks += 1
                 blkend = start(revschunk[-1]) + length(revschunk[-1])
                 blksize = blkend - start(revschunk[0])
 
                 readsize += blksize
                 if largestblock < blksize:
                     largestblock = blksize
 
             if readsize:
                 readdensity = float(chainsize) / float(readsize)
             else:
                 readdensity = 1
 
             fm.write('readsize largestblock readdensity srchunks',
                      ' %10d %10d %9.5f %8d',
                      readsize, largestblock, readdensity, srchunks,
                      readsize=readsize, largestblock=largestblock,
                      readdensity=readdensity, srchunks=srchunks)
 
         fm.plain('\n')
 
     fm.end()
 
 @command('debugdirstate|debugstate',
     [('', 'nodates', None, _('do not display the saved mtime (DEPRECATED)')),
      ('', 'dates', True, _('display the saved mtime')),
      ('', 'datesort', None, _('sort by saved mtime'))],
     _('[OPTION]...'))
 def debugstate(ui, repo, **opts):
     """show the contents of the current dirstate"""
 
     nodates = not opts[r'dates']
     if opts.get(r'nodates') is not None:
         nodates = True
     datesort = opts.get(r'datesort')
 
     if datesort:
         keyfunc = lambda x: (x[1][3], x[0]) # sort by mtime, then by filename
     else:
         keyfunc = None # sort by filename
     for file_, ent in sorted(repo.dirstate._map.iteritems(), key=keyfunc):
         if ent[3] == -1:
             timestr = 'unset               '
         elif nodates:
             timestr = 'set                 '
         else:
             timestr = time.strftime(r"%Y-%m-%d %H:%M:%S ",
                                     time.localtime(ent[3]))
             timestr = encoding.strtolocal(timestr)
         if ent[1] & 0o20000:
             mode = 'lnk'
         else:
             mode = '%3o' % (ent[1] & 0o777 & ~util.umask)
         ui.write("%c %s %10d %s%s\n" % (ent[0], mode, ent[2], timestr, file_))
     for f in repo.dirstate.copies():
         ui.write(_("copy: %s -> %s\n") % (repo.dirstate.copied(f), f))
 
 @command('debugdiscovery',
     [('', 'old', None, _('use old-style discovery')),
     ('', 'nonheads', None,
      _('use old-style discovery with non-heads included')),
     ('', 'rev', [], 'restrict discovery to this set of revs'),
     ('', 'seed', '12323', 'specify the random seed use for discovery'),
     ] + cmdutil.remoteopts,
     _('[--rev REV] [OTHER]'))
 def debugdiscovery(ui, repo, remoteurl="default", **opts):
     """runs the changeset discovery protocol in isolation"""
     opts = pycompat.byteskwargs(opts)
     remoteurl, branches = hg.parseurl(ui.expandpath(remoteurl))
     remote = hg.peer(repo, opts, remoteurl)
     ui.status(_('comparing with %s\n') % util.hidepassword(remoteurl))
 
     # make sure tests are repeatable
     random.seed(int(opts['seed']))
 
 
 
     if opts.get('old'):
         def doit(pushedrevs, remoteheads, remote=remote):
             if not util.safehasattr(remote, 'branches'):
                 # enable in-client legacy support
                 remote = localrepo.locallegacypeer(remote.local())
             common, _in, hds = treediscovery.findcommonincoming(repo, remote,
                                                                 force=True)
             common = set(common)
             if not opts.get('nonheads'):
                 ui.write(("unpruned common: %s\n") %
                          " ".join(sorted(short(n) for n in common)))
 
                 clnode = repo.changelog.node
                 common = repo.revs('heads(::%ln)', common)
                 common = {clnode(r) for r in common}
             return common, hds
     else:
         def doit(pushedrevs, remoteheads, remote=remote):
             nodes = None
             if pushedrevs:
                 revs = scmutil.revrange(repo, pushedrevs)
                 nodes = [repo[r].node() for r in revs]
             common, any, hds = setdiscovery.findcommonheads(ui, repo, remote,
                                                             ancestorsof=nodes)
             return common, hds
 
     remoterevs, _checkout = hg.addbranchrevs(repo, remote, branches, revs=None)
     localrevs = opts['rev']
     with util.timedcm('debug-discovery') as t:
         common, hds = doit(localrevs, remoterevs)
 
     # compute all statistics
     common = set(common)
     rheads = set(hds)
     lheads = set(repo.heads())
 
     data = {}
     data['elapsed'] = t.elapsed
     data['nb-common'] = len(common)
     data['nb-common-local'] = len(common & lheads)
     data['nb-common-remote'] = len(common & rheads)
     data['nb-common-both'] = len(common & rheads & lheads)
     data['nb-local'] = len(lheads)
     data['nb-local-missing'] = data['nb-local'] - data['nb-common-local']
     data['nb-remote'] = len(rheads)
     data['nb-remote-unknown'] = data['nb-remote'] - data['nb-common-remote']
     data['nb-revs'] = len(repo.revs('all()'))
     data['nb-revs-common'] = len(repo.revs('::%ln', common))
     data['nb-revs-missing'] = data['nb-revs'] - data['nb-revs-common']
 
     # display discovery summary
     ui.write(("elapsed time:  %(elapsed)f seconds\n") % data)
     ui.write(("heads summary:\n"))
     ui.write(("  total common heads:  %(nb-common)9d\n") % data)
     ui.write(("    also local heads:  %(nb-common-local)9d\n") % data)
     ui.write(("    also remote heads: %(nb-common-remote)9d\n") % data)
     ui.write(("    both:              %(nb-common-both)9d\n") % data)
     ui.write(("  local heads:         %(nb-local)9d\n") % data)
     ui.write(("    common:            %(nb-common-local)9d\n") % data)
     ui.write(("    missing:           %(nb-local-missing)9d\n") % data)
     ui.write(("  remote heads:        %(nb-remote)9d\n") % data)
     ui.write(("    common:            %(nb-common-remote)9d\n") % data)
     ui.write(("    unknown:           %(nb-remote-unknown)9d\n") % data)
     ui.write(("local changesets:      %(nb-revs)9d\n") % data)
     ui.write(("  common:              %(nb-revs-common)9d\n") % data)
     ui.write(("  missing:             %(nb-revs-missing)9d\n") % data)
 
     if ui.verbose:
         ui.write(("common heads: %s\n") %
                  " ".join(sorted(short(n) for n in common)))
 
 _chunksize = 4 << 10
 
 @command('debugdownload',
     [
         ('o', 'output', '', _('path')),
     ],
     optionalrepo=True)
 def debugdownload(ui, repo, url, output=None, **opts):
     """download a resource using Mercurial logic and config
     """
     fh = urlmod.open(ui, url, output)
 
     dest = ui
     if output:
         dest = open(output, "wb", _chunksize)
     try:
         data = fh.read(_chunksize)
         while data:
             dest.write(data)
             data = fh.read(_chunksize)
     finally:
         if output:
             dest.close()
 
 @command('debugextensions', cmdutil.formatteropts, [], optionalrepo=True)
 def debugextensions(ui, repo, **opts):
     '''show information about active extensions'''
     opts = pycompat.byteskwargs(opts)
     exts = extensions.extensions(ui)
     hgver = util.version()
     fm = ui.formatter('debugextensions', opts)
     for extname, extmod in sorted(exts, key=operator.itemgetter(0)):
         isinternal = extensions.ismoduleinternal(extmod)
         extsource = pycompat.fsencode(extmod.__file__)
         if isinternal:
             exttestedwith = []  # never expose magic string to users
         else:
             exttestedwith = getattr(extmod, 'testedwith', '').split()
         extbuglink = getattr(extmod, 'buglink', None)
 
         fm.startitem()
 
         if ui.quiet or ui.verbose:
             fm.write('name', '%s\n', extname)
         else:
             fm.write('name', '%s', extname)
             if isinternal or hgver in exttestedwith:
                 fm.plain('\n')
             elif not exttestedwith:
                 fm.plain(_(' (untested!)\n'))
             else:
                 lasttestedversion = exttestedwith[-1]
                 fm.plain(' (%s!)\n' % lasttestedversion)
 
         fm.condwrite(ui.verbose and extsource, 'source',
                  _('  location: %s\n'), extsource or "")
 
         if ui.verbose:
             fm.plain(_('  bundled: %s\n') % ['no', 'yes'][isinternal])
         fm.data(bundled=isinternal)
 
         fm.condwrite(ui.verbose and exttestedwith, 'testedwith',
                      _('  tested with: %s\n'),
                      fm.formatlist(exttestedwith, name='ver'))
 
         fm.condwrite(ui.verbose and extbuglink, 'buglink',
                  _('  bug reporting: %s\n'), extbuglink or "")
 
     fm.end()
 
 @command('debugfileset',
     [('r', 'rev', '', _('apply the filespec on this revision'), _('REV')),
      ('', 'all-files', False,
       _('test files from all revisions and working directory')),
      ('s', 'show-matcher', None,
       _('print internal representation of matcher')),
      ('p', 'show-stage', [],
       _('print parsed tree at the given stage'), _('NAME'))],
     _('[-r REV] [--all-files] [OPTION]... FILESPEC'))
 def debugfileset(ui, repo, expr, **opts):
     '''parse and apply a fileset specification'''
     from . import fileset
     fileset.symbols # force import of fileset so we have predicates to optimize
     opts = pycompat.byteskwargs(opts)
     ctx = scmutil.revsingle(repo, opts.get('rev'), None)
 
     stages = [
         ('parsed', pycompat.identity),
         ('analyzed', filesetlang.analyze),
         ('optimized', filesetlang.optimize),
     ]
     stagenames = set(n for n, f in stages)
 
     showalways = set()
     if ui.verbose and not opts['show_stage']:
         # show parsed tree by --verbose (deprecated)
         showalways.add('parsed')
     if opts['show_stage'] == ['all']:
         showalways.update(stagenames)
     else:
         for n in opts['show_stage']:
             if n not in stagenames:
                 raise error.Abort(_('invalid stage name: %s') % n)
         showalways.update(opts['show_stage'])
 
     tree = filesetlang.parse(expr)
     for n, f in stages:
         tree = f(tree)
         if n in showalways:
             if opts['show_stage'] or n != 'parsed':
                 ui.write(("* %s:\n") % n)
             ui.write(filesetlang.prettyformat(tree), "\n")
 
     files = set()
     if opts['all_files']:
         for r in repo:
             c = repo[r]
             files.update(c.files())
             files.update(c.substate)
     if opts['all_files'] or ctx.rev() is None:
         wctx = repo[None]
         files.update(repo.dirstate.walk(scmutil.matchall(repo),
                                         subrepos=list(wctx.substate),
                                         unknown=True, ignored=True))
         files.update(wctx.substate)
     else:
         files.update(ctx.files())
         files.update(ctx.substate)
 
     m = ctx.matchfileset(expr)
     if opts['show_matcher'] or (opts['show_matcher'] is None and ui.verbose):
         ui.write(('* matcher:\n'), stringutil.prettyrepr(m), '\n')
     for f in sorted(files):
         if not m(f):
             continue
         ui.write("%s\n" % f)
 
 @command('debugformat',
          [] + cmdutil.formatteropts)
 def debugformat(ui, repo, **opts):
     """display format information about the current repository
 
     Use --verbose to get extra information about current config value and
     Mercurial default."""
     opts = pycompat.byteskwargs(opts)
     maxvariantlength = max(len(fv.name) for fv in upgrade.allformatvariant)
     maxvariantlength = max(len('format-variant'), maxvariantlength)
 
     def makeformatname(name):
         return '%s:' + (' ' * (maxvariantlength - len(name)))
 
     fm = ui.formatter('debugformat', opts)
     if fm.isplain():
         def formatvalue(value):
             if util.safehasattr(value, 'startswith'):
                 return value
             if value:
                 return 'yes'
             else:
                 return 'no'
     else:
         formatvalue = pycompat.identity
 
     fm.plain('format-variant')
     fm.plain(' ' * (maxvariantlength - len('format-variant')))
     fm.plain(' repo')
     if ui.verbose:
         fm.plain(' config default')
     fm.plain('\n')
     for fv in upgrade.allformatvariant:
         fm.startitem()
         repovalue = fv.fromrepo(repo)
         configvalue = fv.fromconfig(repo)
 
         if repovalue != configvalue:
             namelabel = 'formatvariant.name.mismatchconfig'
             repolabel = 'formatvariant.repo.mismatchconfig'
         elif repovalue != fv.default:
             namelabel = 'formatvariant.name.mismatchdefault'
             repolabel = 'formatvariant.repo.mismatchdefault'
         else:
             namelabel = 'formatvariant.name.uptodate'
             repolabel = 'formatvariant.repo.uptodate'
 
         fm.write('name', makeformatname(fv.name), fv.name,
                  label=namelabel)
         fm.write('repo', ' %3s', formatvalue(repovalue),
                  label=repolabel)
         if fv.default != configvalue:
             configlabel = 'formatvariant.config.special'
         else:
             configlabel = 'formatvariant.config.default'
         fm.condwrite(ui.verbose, 'config', ' %6s', formatvalue(configvalue),
                      label=configlabel)
         fm.condwrite(ui.verbose, 'default', ' %7s', formatvalue(fv.default),
                      label='formatvariant.default')
         fm.plain('\n')
     fm.end()
 
 @command('debugfsinfo', [], _('[PATH]'), norepo=True)
 def debugfsinfo(ui, path="."):
     """show information detected about current filesystem"""
     ui.write(('path: %s\n') % path)
     ui.write(('mounted on: %s\n') % (util.getfsmountpoint(path) or '(unknown)'))
     ui.write(('exec: %s\n') % (util.checkexec(path) and 'yes' or 'no'))
     ui.write(('fstype: %s\n') % (util.getfstype(path) or '(unknown)'))
     ui.write(('symlink: %s\n') % (util.checklink(path) and 'yes' or 'no'))
     ui.write(('hardlink: %s\n') % (util.checknlink(path) and 'yes' or 'no'))
     casesensitive = '(unknown)'
     try:
         with pycompat.namedtempfile(prefix='.debugfsinfo', dir=path) as f:
             casesensitive = util.fscasesensitive(f.name) and 'yes' or 'no'
     except OSError:
         pass
     ui.write(('case-sensitive: %s\n') % casesensitive)
 
 @command('debuggetbundle',
     [('H', 'head', [], _('id of head node'), _('ID')),
     ('C', 'common', [], _('id of common node'), _('ID')),
     ('t', 'type', 'bzip2', _('bundle compression type to use'), _('TYPE'))],
     _('REPO FILE [-H|-C ID]...'),
     norepo=True)
 def debuggetbundle(ui, repopath, bundlepath, head=None, common=None, **opts):
     """retrieves a bundle from a repo
 
     Every ID must be a full-length hex node id string. Saves the bundle to the
     given file.
     """
     opts = pycompat.byteskwargs(opts)
     repo = hg.peer(ui, opts, repopath)
     if not repo.capable('getbundle'):
         raise error.Abort("getbundle() not supported by target repository")
     args = {}
     if common:
         args[r'common'] = [bin(s) for s in common]
     if head:
         args[r'heads'] = [bin(s) for s in head]
     # TODO: get desired bundlecaps from command line.
     args[r'bundlecaps'] = None
     bundle = repo.getbundle('debug', **args)
 
     bundletype = opts.get('type', 'bzip2').lower()
     btypes = {'none': 'HG10UN',
               'bzip2': 'HG10BZ',
               'gzip': 'HG10GZ',
               'bundle2': 'HG20'}
     bundletype = btypes.get(bundletype)
     if bundletype not in bundle2.bundletypes:
         raise error.Abort(_('unknown bundle type specified with --type'))
     bundle2.writebundle(ui, bundle, bundlepath, bundletype)
 
 @command('debugignore', [], '[FILE]')
 def debugignore(ui, repo, *files, **opts):
     """display the combined ignore pattern and information about ignored files
 
     With no argument display the combined ignore pattern.
 
     Given space separated file names, shows if the given file is ignored and
     if so, show the ignore rule (file and line number) that matched it.
     """
     ignore = repo.dirstate._ignore
     if not files:
         # Show all the patterns
         ui.write("%s\n" % pycompat.byterepr(ignore))
     else:
         m = scmutil.match(repo[None], pats=files)
         uipathfn = scmutil.getuipathfn(repo, legacyrelativevalue=True)
         for f in m.files():
             nf = util.normpath(f)
             ignored = None
             ignoredata = None
             if nf != '.':
                 if ignore(nf):
                     ignored = nf
                     ignoredata = repo.dirstate._ignorefileandline(nf)
                 else:
                     for p in util.finddirs(nf):
                         if ignore(p):
                             ignored = p
                             ignoredata = repo.dirstate._ignorefileandline(p)
                             break
             if ignored:
                 if ignored == nf:
                     ui.write(_("%s is ignored\n") % uipathfn(f))
                 else:
                     ui.write(_("%s is ignored because of "
                                "containing directory %s\n")
                              % (uipathfn(f), ignored))
                 ignorefile, lineno, line = ignoredata
                 ui.write(_("(ignore rule in %s, line %d: '%s')\n")
                          % (ignorefile, lineno, line))
             else:
                 ui.write(_("%s is not ignored\n") % uipathfn(f))
 
 @command('debugindex', cmdutil.debugrevlogopts + cmdutil.formatteropts,
          _('-c|-m|FILE'))
 def debugindex(ui, repo, file_=None, **opts):
     """dump index data for a storage primitive"""
     opts = pycompat.byteskwargs(opts)
     store = cmdutil.openstorage(repo, 'debugindex', file_, opts)
 
     if ui.debugflag:
         shortfn = hex
     else:
         shortfn = short
 
     idlen = 12
     for i in store:
         idlen = len(shortfn(store.node(i)))
         break
 
     fm = ui.formatter('debugindex', opts)
     fm.plain(b'   rev linkrev %s %s p2\n' % (
         b'nodeid'.ljust(idlen),
         b'p1'.ljust(idlen)))
 
     for rev in store:
         node = store.node(rev)
         parents = store.parents(node)
 
         fm.startitem()
         fm.write(b'rev', b'%6d ', rev)
         fm.write(b'linkrev', '%7d ', store.linkrev(rev))
         fm.write(b'node', '%s ', shortfn(node))
         fm.write(b'p1', '%s ', shortfn(parents[0]))
         fm.write(b'p2', '%s', shortfn(parents[1]))
         fm.plain(b'\n')
 
     fm.end()
 
 @command('debugindexdot', cmdutil.debugrevlogopts,
     _('-c|-m|FILE'), optionalrepo=True)
 def debugindexdot(ui, repo, file_=None, **opts):
     """dump an index DAG as a graphviz dot file"""
     opts = pycompat.byteskwargs(opts)
     r = cmdutil.openstorage(repo, 'debugindexdot', file_, opts)
     ui.write(("digraph G {\n"))
     for i in r:
         node = r.node(i)
         pp = r.parents(node)
         ui.write("\t%d -> %d\n" % (r.rev(pp[0]), i))
         if pp[1] != nullid:
             ui.write("\t%d -> %d\n" % (r.rev(pp[1]), i))
     ui.write("}\n")
 
 @command('debugindexstats', [])
 def debugindexstats(ui, repo):
     """show stats related to the changelog index"""
     repo.changelog.shortest(nullid, 1)
     index = repo.changelog.index
     if not util.safehasattr(index, 'stats'):
         raise error.Abort(_('debugindexstats only works with native code'))
     for k, v in sorted(index.stats().items()):
         ui.write('%s: %d\n' % (k, v))
 
 @command('debuginstall', [] + cmdutil.formatteropts, '', norepo=True)
 def debuginstall(ui, **opts):
     '''test Mercurial installation
 
     Returns 0 on success.
     '''
     opts = pycompat.byteskwargs(opts)
 
     problems = 0
 
     fm = ui.formatter('debuginstall', opts)
     fm.startitem()
 
     # encoding
     fm.write('encoding', _("checking encoding (%s)...\n"), encoding.encoding)
     err = None
     try:
         codecs.lookup(pycompat.sysstr(encoding.encoding))
     except LookupError as inst:
         err = stringutil.forcebytestr(inst)
         problems += 1
     fm.condwrite(err, 'encodingerror', _(" %s\n"
                  " (check that your locale is properly set)\n"), err)
 
     # Python
     fm.write('pythonexe', _("checking Python executable (%s)\n"),
              pycompat.sysexecutable)
     fm.write('pythonver', _("checking Python version (%s)\n"),
              ("%d.%d.%d" % sys.version_info[:3]))
     fm.write('pythonlib', _("checking Python lib (%s)...\n"),
              os.path.dirname(pycompat.fsencode(os.__file__)))
 
     security = set(sslutil.supportedprotocols)
     if sslutil.hassni:
         security.add('sni')
 
     fm.write('pythonsecurity', _("checking Python security support (%s)\n"),
              fm.formatlist(sorted(security), name='protocol',
                            fmt='%s', sep=','))
 
     # These are warnings, not errors. So don't increment problem count. This
     # may change in the future.
     if 'tls1.2' not in security:
         fm.plain(_('  TLS 1.2 not supported by Python install; '
                    'network connections lack modern security\n'))
     if 'sni' not in security:
         fm.plain(_('  SNI not supported by Python install; may have '
                    'connectivity issues with some servers\n'))
 
     # TODO print CA cert info
 
     # hg version
     hgver = util.version()
     fm.write('hgver', _("checking Mercurial version (%s)\n"),
              hgver.split('+')[0])
     fm.write('hgverextra', _("checking Mercurial custom build (%s)\n"),
              '+'.join(hgver.split('+')[1:]))
 
     # compiled modules
     fm.write('hgmodulepolicy', _("checking module policy (%s)\n"),
              policy.policy)
     fm.write('hgmodules', _("checking installed modules (%s)...\n"),
              os.path.dirname(pycompat.fsencode(__file__)))
 
-    if policy.policy in ('c', 'allow'):
+    rustandc = policy.policy in ('rust+c', 'rust+c-allow')
+    rustext = rustandc  # for now, that's the only case
+    cext = policy.policy in ('c', 'allow') or rustandc
+    nopure = cext or rustext
+    if nopure:
         err = None
         try:
-            from .cext import (
-                base85,
-                bdiff,
-                mpatch,
-                osutil,
-            )
-            dir(bdiff), dir(mpatch), dir(base85), dir(osutil) # quiet pyflakes
+            if cext:
+                from .cext import (
+                    base85,
+                    bdiff,
+                    mpatch,
+                    osutil,
+                )
+                # quiet pyflakes
+                dir(bdiff), dir(mpatch), dir(base85), dir(osutil)
+            if rustext:
+                from .rustext import (
+                    ancestor,
+                    dirstate,
+                )
+                dir(ancestor), dir(dirstate) # quiet pyflakes
         except Exception as inst:
             err = stringutil.forcebytestr(inst)
             problems += 1
         fm.condwrite(err, 'extensionserror', " %s\n", err)
 
     compengines = util.compengines._engines.values()
     fm.write('compengines', _('checking registered compression engines (%s)\n'),
              fm.formatlist(sorted(e.name() for e in compengines),
                            name='compengine', fmt='%s', sep=', '))
     fm.write('compenginesavail', _('checking available compression engines '
                                    '(%s)\n'),
              fm.formatlist(sorted(e.name() for e in compengines
                                   if e.available()),
                            name='compengine', fmt='%s', sep=', '))
     wirecompengines = compression.compengines.supportedwireengines(
         compression.SERVERROLE)
     fm.write('compenginesserver', _('checking available compression engines '
                                     'for wire protocol (%s)\n'),
              fm.formatlist([e.name() for e in wirecompengines
                             if e.wireprotosupport()],
                            name='compengine', fmt='%s', sep=', '))
     re2 = 'missing'
     if util._re2:
         re2 = 'available'
     fm.plain(_('checking "re2" regexp engine (%s)\n') % re2)
     fm.data(re2=bool(util._re2))
 
     # templates
     p = templater.templatepaths()
     fm.write('templatedirs', 'checking templates (%s)...\n', ' '.join(p))
     fm.condwrite(not p, '', _(" no template directories found\n"))
     if p:
         m = templater.templatepath("map-cmdline.default")
         if m:
             # template found, check if it is working
             err = None
             try:
                 templater.templater.frommapfile(m)
             except Exception as inst:
                 err = stringutil.forcebytestr(inst)
                 p = None
             fm.condwrite(err, 'defaulttemplateerror', " %s\n", err)
         else:
             p = None
         fm.condwrite(p, 'defaulttemplate',
                      _("checking default template (%s)\n"), m)
         fm.condwrite(not m, 'defaulttemplatenotfound',
                      _(" template '%s' not found\n"), "default")
     if not p:
         problems += 1
     fm.condwrite(not p, '',
                  _(" (templates seem to have been installed incorrectly)\n"))
 
     # editor
     editor = ui.geteditor()
     editor = util.expandpath(editor)
     editorbin = procutil.shellsplit(editor)[0]
     fm.write('editor', _("checking commit editor... (%s)\n"), editorbin)
     cmdpath = procutil.findexe(editorbin)
     fm.condwrite(not cmdpath and editor == 'vi', 'vinotfound',
                  _(" No commit editor set and can't find %s in PATH\n"
                    " (specify a commit editor in your configuration"
                    " file)\n"), not cmdpath and editor == 'vi' and editorbin)
     fm.condwrite(not cmdpath and editor != 'vi', 'editornotfound',
                  _(" Can't find editor '%s' in PATH\n"
                    " (specify a commit editor in your configuration"
                    " file)\n"), not cmdpath and editorbin)
     if not cmdpath and editor != 'vi':
         problems += 1
 
     # check username
     username = None
     err = None
     try:
         username = ui.username()
     except error.Abort as e:
         err = stringutil.forcebytestr(e)
         problems += 1
 
     fm.condwrite(username, 'username',  _("checking username (%s)\n"), username)
     fm.condwrite(err, 'usernameerror', _("checking username...\n %s\n"
         " (specify a username in your configuration file)\n"), err)
 
     fm.condwrite(not problems, '',
                  _("no problems detected\n"))
     if not problems:
         fm.data(problems=problems)
     fm.condwrite(problems, 'problems',
                  _("%d problems detected,"
                    " please check your install!\n"), problems)
     fm.end()
 
     return problems
 
 @command('debugknown', [], _('REPO ID...'), norepo=True)
 def debugknown(ui, repopath, *ids, **opts):
     """test whether node ids are known to a repo
 
     Every ID must be a full-length hex node id string. Returns a list of 0s
     and 1s indicating unknown/known.
     """
     opts = pycompat.byteskwargs(opts)
     repo = hg.peer(ui, opts, repopath)
     if not repo.capable('known'):
         raise error.Abort("known() not supported by target repository")
     flags = repo.known([bin(s) for s in ids])
     ui.write("%s\n" % ("".join([f and "1" or "0" for f in flags])))
 
 @command('debuglabelcomplete', [], _('LABEL...'))
 def debuglabelcomplete(ui, repo, *args):
     '''backwards compatibility with old bash completion scripts (DEPRECATED)'''
     debugnamecomplete(ui, repo, *args)
 
 @command('debuglocks',
          [('L', 'force-lock', None, _('free the store lock (DANGEROUS)')),
           ('W', 'force-wlock', None,
            _('free the working state lock (DANGEROUS)')),
           ('s', 'set-lock', None, _('set the store lock until stopped')),
           ('S', 'set-wlock', None,
            _('set the working state lock until stopped'))],
          _('[OPTION]...'))
 def debuglocks(ui, repo, **opts):
     """show or modify state of locks
 
     By default, this command will show which locks are held. This
     includes the user and process holding the lock, the amount of time
     the lock has been held, and the machine name where the process is
     running if it's not local.
 
     Locks protect the integrity of Mercurial's data, so should be
     treated with care. System crashes or other interruptions may cause
     locks to not be properly released, though Mercurial will usually
     detect and remove such stale locks automatically.
 
     However, detecting stale locks may not always be possible (for
     instance, on a shared filesystem). Removing locks may also be
     blocked by filesystem permissions.
 
     Setting a lock will prevent other commands from changing the data.
     The command will wait until an interruption (SIGINT, SIGTERM, ...) occurs.
     The set locks are removed when the command exits.
 
     Returns 0 if no locks are held.
 
     """
 
     if opts.get(r'force_lock'):
         repo.svfs.unlink('lock')
     if opts.get(r'force_wlock'):
         repo.vfs.unlink('wlock')
     if opts.get(r'force_lock') or opts.get(r'force_wlock'):
         return 0
 
     locks = []
     try:
         if opts.get(r'set_wlock'):
             try:
                 locks.append(repo.wlock(False))
             except error.LockHeld:
                 raise error.Abort(_('wlock is already held'))
         if opts.get(r'set_lock'):
             try:
                 locks.append(repo.lock(False))
             except error.LockHeld:
                 raise error.Abort(_('lock is already held'))
         if len(locks):
             ui.promptchoice(_("ready to release the lock (y)? $$ &Yes"))
             return 0
     finally:
         release(*locks)
 
     now = time.time()
     held = 0
 
     def report(vfs, name, method):
         # this causes stale locks to get reaped for more accurate reporting
         try:
             l = method(False)
         except error.LockHeld:
             l = None
 
         if l:
             l.release()
         else:
             try:
                 st = vfs.lstat(name)
                 age = now - st[stat.ST_MTIME]
                 user = util.username(st.st_uid)
                 locker = vfs.readlock(name)
                 if ":" in locker:
                     host, pid = locker.split(':')
                     if host == socket.gethostname():
                         locker = 'user %s, process %s' % (user or b'None', pid)
                     else:
                         locker = ('user %s, process %s, host %s'
                                   % (user or b'None', pid, host))
                 ui.write(("%-6s %s (%ds)\n") % (name + ":", locker, age))
                 return 1
             except OSError as e:
                 if e.errno != errno.ENOENT:
                     raise
 
         ui.write(("%-6s free\n") % (name + ":"))
         return 0
 
     held += report(repo.svfs, "lock", repo.lock)
     held += report(repo.vfs, "wlock", repo.wlock)
 
     return held
 
 @command('debugmanifestfulltextcache', [
         ('', 'clear', False, _('clear the cache')),
         ('a', 'add', [], _('add the given manifest nodes to the cache'),
          _('NODE'))
     ], '')
 def debugmanifestfulltextcache(ui, repo, add=(), **opts):
     """show, clear or amend the contents of the manifest fulltext cache"""
 
     def getcache():
         r = repo.manifestlog.getstorage(b'')
         try:
             return r._fulltextcache
         except AttributeError:
             msg = _("Current revlog implementation doesn't appear to have a "
                     "manifest fulltext cache\n")
             raise error.Abort(msg)
 
     if opts.get(r'clear'):
         with repo.wlock():
             cache = getcache()
             cache.clear(clear_persisted_data=True)
             return
 
     if add:
         with repo.wlock():
             m = repo.manifestlog
             store = m.getstorage(b'')
             for n in add:
                 try:
                     manifest = m[store.lookup(n)]
                 except error.LookupError as e:
                     raise error.Abort(e, hint="Check your manifest node id")
                 manifest.read()  # stores revisision in cache too
             return
 
     cache = getcache()
     if not len(cache):
         ui.write(_('cache empty\n'))
     else:
         ui.write(
             _('cache contains %d manifest entries, in order of most to '
               'least recent:\n') % (len(cache),))
         totalsize = 0
         for nodeid in cache:
             # Use cache.get to not update the LRU order
             data = cache.peek(nodeid)
             size = len(data)
             totalsize += size + 24   # 20 bytes nodeid, 4 bytes size
             ui.write(_('id: %s, size %s\n') % (
                 hex(nodeid), util.bytecount(size)))
         ondisk = cache._opener.stat('manifestfulltextcache').st_size
         ui.write(
             _('total cache data size %s, on-disk %s\n') % (
                 util.bytecount(totalsize), util.bytecount(ondisk))
         )
 
 @command('debugmergestate', [], '')
 def debugmergestate(ui, repo, *args):
     """print merge state
 
     Use --verbose to print out information about whether v1 or v2 merge state
     was chosen."""
     def _hashornull(h):
         if h == nullhex:
             return 'null'
         else:
             return h
 
     def printrecords(version):
         ui.write(('* version %d records\n') % version)
         if version == 1:
             records = v1records
         else:
             records = v2records
 
         for rtype, record in records:
             # pretty print some record types
             if rtype == 'L':
                 ui.write(('local: %s\n') % record)
             elif rtype == 'O':
                 ui.write(('other: %s\n') % record)
             elif rtype == 'm':
                 driver, mdstate = record.split('\0', 1)
                 ui.write(('merge driver: %s (state "%s")\n')
                          % (driver, mdstate))
             elif rtype in 'FDC':
                 r = record.split('\0')
                 f, state, hash, lfile, afile, anode, ofile = r[0:7]
                 if version == 1:
                     onode = 'not stored in v1 format'
                     flags = r[7]
                 else:
                     onode, flags = r[7:9]
                 ui.write(('file: %s (record type "%s", state "%s", hash %s)\n')
                          % (f, rtype, state, _hashornull(hash)))
                 ui.write(('  local path: %s (flags "%s")\n') % (lfile, flags))
                 ui.write(('  ancestor path: %s (node %s)\n')
                          % (afile, _hashornull(anode)))
                 ui.write(('  other path: %s (node %s)\n')
                          % (ofile, _hashornull(onode)))
             elif rtype == 'f':
                 filename, rawextras = record.split('\0', 1)
                 extras = rawextras.split('\0')
                 i = 0
                 extrastrings = []
                 while i < len(extras):
                     extrastrings.append('%s = %s' % (extras[i], extras[i + 1]))
                     i += 2
 
                 ui.write(('file extras: %s (%s)\n')
                          % (filename, ', '.join(extrastrings)))
             elif rtype == 'l':
                 labels = record.split('\0', 2)
                 labels = [l for l in labels if len(l) > 0]
                 ui.write(('labels:\n'))
                 ui.write(('  local: %s\n' % labels[0]))
                 ui.write(('  other: %s\n' % labels[1]))
                 if len(labels) > 2:
                     ui.write(('  base:  %s\n' % labels[2]))
             else:
                 ui.write(('unrecognized entry: %s\t%s\n')
                          % (rtype, record.replace('\0', '\t')))
 
     # Avoid mergestate.read() since it may raise an exception for unsupported
     # merge state records. We shouldn't be doing this, but this is OK since this
     # command is pretty low-level.
     ms = mergemod.mergestate(repo)
 
     # sort so that reasonable information is on top
     v1records = ms._readrecordsv1()
     v2records = ms._readrecordsv2()
     order = 'LOml'
     def key(r):
         idx = order.find(r[0])
         if idx == -1:
             return (1, r[1])
         else:
             return (0, idx)
     v1records.sort(key=key)
     v2records.sort(key=key)
 
     if not v1records and not v2records:
         ui.write(('no merge state found\n'))
     elif not v2records:
         ui.note(('no version 2 merge state\n'))
         printrecords(1)
     elif ms._v1v2match(v1records, v2records):
         ui.note(('v1 and v2 states match: using v2\n'))
         printrecords(2)
     else:
         ui.note(('v1 and v2 states mismatch: using v1\n'))
         printrecords(1)
         if ui.verbose:
             printrecords(2)
 
 @command('debugnamecomplete', [], _('NAME...'))
 def debugnamecomplete(ui, repo, *args):
     '''complete "names" - tags, open branch names, bookmark names'''
 
     names = set()
     # since we previously only listed open branches, we will handle that
     # specially (after this for loop)
     for name, ns in repo.names.iteritems():
         if name != 'branches':
             names.update(ns.listnames(repo))
     names.update(tag for (tag, heads, tip, closed)
                  in repo.branchmap().iterbranches() if not closed)
     completions = set()
     if not args:
         args = ['']
     for a in args:
         completions.update(n for n in names if n.startswith(a))
     ui.write('\n'.join(sorted(completions)))
     ui.write('\n')
 
 @command('debugobsolete',
         [('', 'flags', 0, _('markers flag')),
          ('', 'record-parents', False,
           _('record parent information for the precursor')),
          ('r', 'rev', [], _('display markers relevant to REV')),
          ('', 'exclusive', False, _('restrict display to markers only '
                                     'relevant to REV')),
          ('', 'index', False, _('display index of the marker')),
          ('', 'delete', [], _('delete markers specified by indices')),
         ] + cmdutil.commitopts2 + cmdutil.formatteropts,
          _('[OBSOLETED [REPLACEMENT ...]]'))
 def debugobsolete(ui, repo, precursor=None, *successors, **opts):
     """create arbitrary obsolete marker
 
     With no arguments, displays the list of obsolescence markers."""
 
     opts = pycompat.byteskwargs(opts)
 
     def parsenodeid(s):
         try:
             # We do not use revsingle/revrange functions here to accept
             # arbitrary node identifiers, possibly not present in the
             # local repository.
             n = bin(s)
             if len(n) != len(nullid):
                 raise TypeError()
             return n
         except TypeError:
             raise error.Abort('changeset references must be full hexadecimal '
                              'node identifiers')
 
     if opts.get('delete'):
         indices = []
         for v in opts.get('delete'):
             try:
                 indices.append(int(v))
             except ValueError:
                 raise error.Abort(_('invalid index value: %r') % v,
                                   hint=_('use integers for indices'))
 
         if repo.currenttransaction():
             raise error.Abort(_('cannot delete obsmarkers in the middle '
                                 'of transaction.'))
 
         with repo.lock():
             n = repair.deleteobsmarkers(repo.obsstore, indices)
             ui.write(_('deleted %i obsolescence markers\n') % n)
 
         return
 
     if precursor is not None:
         if opts['rev']:
             raise error.Abort('cannot select revision when creating marker')
         metadata = {}
         metadata['user'] = encoding.fromlocal(opts['user'] or ui.username())
         succs = tuple(parsenodeid(succ) for succ in successors)
         l = repo.lock()
         try:
             tr = repo.transaction('debugobsolete')
             try:
                 date = opts.get('date')
                 if date:
                     date = dateutil.parsedate(date)
                 else:
                     date = None
                 prec = parsenodeid(precursor)
                 parents = None
                 if opts['record_parents']:
                     if prec not in repo.unfiltered():
                         raise error.Abort('cannot used --record-parents on '
                                          'unknown changesets')
                     parents = repo.unfiltered()[prec].parents()
                     parents = tuple(p.node() for p in parents)
                 repo.obsstore.create(tr, prec, succs, opts['flags'],
                                      parents=parents, date=date,
                                      metadata=metadata, ui=ui)
                 tr.close()
             except ValueError as exc:
                 raise error.Abort(_('bad obsmarker input: %s') %
                                   pycompat.bytestr(exc))
             finally:
                 tr.release()
         finally:
             l.release()
     else:
         if opts['rev']:
             revs = scmutil.revrange(repo, opts['rev'])
             nodes = [repo[r].node() for r in revs]
             markers = list(obsutil.getmarkers(repo, nodes=nodes,
                                                exclusive=opts['exclusive']))
             markers.sort(key=lambda x: x._data)
         else:
             markers = obsutil.getmarkers(repo)
 
         markerstoiter = markers
         isrelevant = lambda m: True
         if opts.get('rev') and opts.get('index'):
             markerstoiter = obsutil.getmarkers(repo)
             markerset = set(markers)
             isrelevant = lambda m: m in markerset
 
         fm = ui.formatter('debugobsolete', opts)
         for i, m in enumerate(markerstoiter):
             if not isrelevant(m):
                 # marker can be irrelevant when we're iterating over a set
                 # of markers (markerstoiter) which is bigger than the set
                 # of markers we want to display (markers)
                 # this can happen if both --index and --rev options are
                 # provided and thus we need to iterate over all of the markers
                 # to get the correct indices, but only display the ones that
                 # are relevant to --rev value
                 continue
             fm.startitem()
             ind = i if opts.get('index') else None
             cmdutil.showmarker(fm, m, index=ind)
         fm.end()
 
 @command('debugp1copies',
          [('r', 'rev', '', _('revision to debug'), _('REV'))],
          _('[-r REV]'))
 def debugp1copies(ui, repo, **opts):
     """dump copy information compared to p1"""
 
     opts = pycompat.byteskwargs(opts)
     ctx = scmutil.revsingle(repo, opts.get('rev'), default=None)
     for dst, src in ctx.p1copies().items():
         ui.write('%s -> %s\n' % (src, dst))
 
 @command('debugp2copies',
          [('r', 'rev', '', _('revision to debug'), _('REV'))],
          _('[-r REV]'))
 def debugp1copies(ui, repo, **opts):
     """dump copy information compared to p2"""
 
     opts = pycompat.byteskwargs(opts)
     ctx = scmutil.revsingle(repo, opts.get('rev'), default=None)
     for dst, src in ctx.p2copies().items():
         ui.write('%s -> %s\n' % (src, dst))
 
 @command('debugpathcomplete',
          [('f', 'full', None, _('complete an entire path')),
           ('n', 'normal', None, _('show only normal files')),
           ('a', 'added', None, _('show only added files')),
           ('r', 'removed', None, _('show only removed files'))],
          _('FILESPEC...'))
 def debugpathcomplete(ui, repo, *specs, **opts):
     '''complete part or all of a tracked path
 
     This command supports shells that offer path name completion. It
     currently completes only files already known to the dirstate.
 
     Completion extends only to the next path segment unless
     --full is specified, in which case entire paths are used.'''
 
     def complete(path, acceptable):
         dirstate = repo.dirstate
         spec = os.path.normpath(os.path.join(encoding.getcwd(), path))
         rootdir = repo.root + pycompat.ossep
         if spec != repo.root and not spec.startswith(rootdir):
             return [], []
         if os.path.isdir(spec):
             spec += '/'
         spec = spec[len(rootdir):]
         fixpaths = pycompat.ossep != '/'
         if fixpaths:
             spec = spec.replace(pycompat.ossep, '/')
         speclen = len(spec)
         fullpaths = opts[r'full']
         files, dirs = set(), set()
         adddir, addfile = dirs.add, files.add
         for f, st in dirstate.iteritems():
             if f.startswith(spec) and st[0] in acceptable:
                 if fixpaths:
                     f = f.replace('/', pycompat.ossep)
                 if fullpaths:
                     addfile(f)
                     continue
                 s = f.find(pycompat.ossep, speclen)
                 if s >= 0:
                     adddir(f[:s])
                 else:
                     addfile(f)
         return files, dirs
 
     acceptable = ''
     if opts[r'normal']:
         acceptable += 'nm'
     if opts[r'added']:
         acceptable += 'a'
     if opts[r'removed']:
         acceptable += 'r'
     cwd = repo.getcwd()
     if not specs:
         specs = ['.']
 
     files, dirs = set(), set()
     for spec in specs:
         f, d = complete(spec, acceptable or 'nmar')
         files.update(f)
         dirs.update(d)
     files.update(dirs)
     ui.write('\n'.join(repo.pathto(p, cwd) for p in sorted(files)))
     ui.write('\n')
 
 @command('debugpathcopies',
          cmdutil.walkopts,
          'hg debugpathcopies REV1 REV2 [FILE]',
          inferrepo=True)
 def debugpathcopies(ui, repo, rev1, rev2, *pats, **opts):
     """show copies between two revisions"""
     ctx1 = scmutil.revsingle(repo, rev1)
     ctx2 = scmutil.revsingle(repo, rev2)
     m = scmutil.match(ctx1, pats, opts)
     for dst, src in sorted(copies.pathcopies(ctx1, ctx2, m).items()):
         ui.write('%s -> %s\n' % (src, dst))
 
 @command('debugpeer', [], _('PATH'), norepo=True)
 def debugpeer(ui, path):
     """establish a connection to a peer repository"""
     # Always enable peer request logging. Requires --debug to display
     # though.
     overrides = {
         ('devel', 'debug.peer-request'): True,
     }
 
     with ui.configoverride(overrides):
         peer = hg.peer(ui, {}, path)
 
         local = peer.local() is not None
         canpush = peer.canpush()
 
         ui.write(_('url: %s\n') % peer.url())
         ui.write(_('local: %s\n') % (_('yes') if local else _('no')))
         ui.write(_('pushable: %s\n') % (_('yes') if canpush else _('no')))
 
 @command('debugpickmergetool',
         [('r', 'rev', '', _('check for files in this revision'), _('REV')),
          ('', 'changedelete', None, _('emulate merging change and delete')),
         ] + cmdutil.walkopts + cmdutil.mergetoolopts,
         _('[PATTERN]...'),
         inferrepo=True)
 def debugpickmergetool(ui, repo, *pats, **opts):
     """examine which merge tool is chosen for specified file
 
     As described in :hg:`help merge-tools`, Mercurial examines
     configurations below in this order to decide which merge tool is
     chosen for specified file.
 
     1. ``--tool`` option
     2. ``HGMERGE`` environment variable
     3. configurations in ``merge-patterns`` section
     4. configuration of ``ui.merge``
     5. configurations in ``merge-tools`` section
     6. ``hgmerge`` tool (for historical reason only)
     7. default tool for fallback (``:merge`` or ``:prompt``)
 
     This command writes out examination result in the style below::
 
         FILE = MERGETOOL
 
     By default, all files known in the first parent context of the
     working directory are examined. Use file patterns and/or -I/-X
     options to limit target files. -r/--rev is also useful to examine
     files in another context without actual updating to it.
 
     With --debug, this command shows warning messages while matching
     against ``merge-patterns`` and so on, too. It is recommended to
     use this option with explicit file patterns and/or -I/-X options,
     because this option increases amount of output per file according
     to configurations in hgrc.
 
     With -v/--verbose, this command shows configurations below at
     first (only if specified).
 
     - ``--tool`` option
     - ``HGMERGE`` environment variable
     - configuration of ``ui.merge``
 
     If merge tool is chosen before matching against
     ``merge-patterns``, this command can't show any helpful
     information, even with --debug. In such case, information above is
     useful to know why a merge tool is chosen.
     """
     opts = pycompat.byteskwargs(opts)
     overrides = {}
     if opts['tool']:
         overrides[('ui', 'forcemerge')] = opts['tool']
         ui.note(('with --tool %r\n') % (pycompat.bytestr(opts['tool'])))
 
     with ui.configoverride(overrides, 'debugmergepatterns'):
         hgmerge = encoding.environ.get("HGMERGE")
         if hgmerge is not None:
             ui.note(('with HGMERGE=%r\n') % (pycompat.bytestr(hgmerge)))
         uimerge = ui.config("ui", "merge")
         if uimerge:
             ui.note(('with ui.merge=%r\n') % (pycompat.bytestr(uimerge)))
 
         ctx = scmutil.revsingle(repo, opts.get('rev'))
         m = scmutil.match(ctx, pats, opts)
         changedelete = opts['changedelete']
         for path in ctx.walk(m):
             fctx = ctx[path]
             try:
                 if not ui.debugflag:
                     ui.pushbuffer(error=True)
                 tool, toolpath = filemerge._picktool(repo, ui, path,
                                                      fctx.isbinary(),
                                                      'l' in fctx.flags(),
                                                      changedelete)
             finally:
                 if not ui.debugflag:
                     ui.popbuffer()
             ui.write(('%s = %s\n') % (path, tool))
 
 @command('debugpushkey', [], _('REPO NAMESPACE [KEY OLD NEW]'), norepo=True)
 def debugpushkey(ui, repopath, namespace, *keyinfo, **opts):
     '''access the pushkey key/value protocol
 
     With two args, list the keys in the given namespace.
 
     With five args, set a key to new if it currently is set to old.
     Reports success or failure.
     '''
 
     target = hg.peer(ui, {}, repopath)
     if keyinfo:
         key, old, new = keyinfo
         with target.commandexecutor() as e:
             r = e.callcommand('pushkey', {
                 'namespace': namespace,
                 'key': key,
                 'old': old,
                 'new': new,
             }).result()
 
         ui.status(pycompat.bytestr(r) + '\n')
         return not r
     else:
         for k, v in sorted(target.listkeys(namespace).iteritems()):
             ui.write("%s\t%s\n" % (stringutil.escapestr(k),
                                    stringutil.escapestr(v)))
 
 @command('debugpvec', [], _('A B'))
 def debugpvec(ui, repo, a, b=None):
     ca = scmutil.revsingle(repo, a)
     cb = scmutil.revsingle(repo, b)
     pa = pvec.ctxpvec(ca)
     pb = pvec.ctxpvec(cb)
     if pa == pb:
         rel = "="
     elif pa > pb:
         rel = ">"
     elif pa < pb:
         rel = "<"
     elif pa | pb:
         rel = "|"
     ui.write(_("a: %s\n") % pa)
     ui.write(_("b: %s\n") % pb)
     ui.write(_("depth(a): %d depth(b): %d\n") % (pa._depth, pb._depth))
     ui.write(_("delta: %d hdist: %d distance: %d relation: %s\n") %
              (abs(pa._depth - pb._depth), pvec._hamming(pa._vec, pb._vec),
               pa.distance(pb), rel))
 
 @command('debugrebuilddirstate|debugrebuildstate',
     [('r', 'rev', '', _('revision to rebuild to'), _('REV')),
      ('', 'minimal', None, _('only rebuild files that are inconsistent with '
                              'the working copy parent')),
     ],
     _('[-r REV]'))
 def debugrebuilddirstate(ui, repo, rev, **opts):
     """rebuild the dirstate as it would look like for the given revision
 
     If no revision is specified the first current parent will be used.
 
     The dirstate will be set to the files of the given revision.
     The actual working directory content or existing dirstate
     information such as adds or removes is not considered.
 
     ``minimal`` will only rebuild the dirstate status for files that claim to be
     tracked but are not in the parent manifest, or that exist in the parent
     manifest but are not in the dirstate. It will not change adds, removes, or
     modified files that are in the working copy parent.
 
     One use of this command is to make the next :hg:`status` invocation
     check the actual file content.
     """
     ctx = scmutil.revsingle(repo, rev)
     with repo.wlock():
         dirstate = repo.dirstate
         changedfiles = None
         # See command doc for what minimal does.
         if opts.get(r'minimal'):
             manifestfiles = set(ctx.manifest().keys())
             dirstatefiles = set(dirstate)
             manifestonly = manifestfiles - dirstatefiles
             dsonly = dirstatefiles - manifestfiles
             dsnotadded = set(f for f in dsonly if dirstate[f] != 'a')
             changedfiles = manifestonly | dsnotadded
 
         dirstate.rebuild(ctx.node(), ctx.manifest(), changedfiles)
 
 @command('debugrebuildfncache', [], '')
 def debugrebuildfncache(ui, repo):
     """rebuild the fncache file"""
     repair.rebuildfncache(ui, repo)
 
 @command('debugrename',
     [('r', 'rev', '', _('revision to debug'), _('REV'))],
     _('[-r REV] [FILE]...'))
 def debugrename(ui, repo, *pats, **opts):
     """dump rename information"""
 
     opts = pycompat.byteskwargs(opts)
     ctx = scmutil.revsingle(repo, opts.get('rev'))
     m = scmutil.match(ctx, pats, opts)
     for abs in ctx.walk(m):
         fctx = ctx[abs]
         o = fctx.filelog().renamed(fctx.filenode())
         rel = repo.pathto(abs)
         if o:
             ui.write(_("%s renamed from %s:%s\n") % (rel, o[0], hex(o[1])))
         else:
             ui.write(_("%s not renamed\n") % rel)
 
 @command('debugrevlog', cmdutil.debugrevlogopts +
     [('d', 'dump', False, _('dump index data'))],
     _('-c|-m|FILE'),
     optionalrepo=True)
 def debugrevlog(ui, repo, file_=None, **opts):
     """show data and statistics about a revlog"""
     opts = pycompat.byteskwargs(opts)
     r = cmdutil.openrevlog(repo, 'debugrevlog', file_, opts)
 
     if opts.get("dump"):
         numrevs = len(r)
         ui.write(("# rev p1rev p2rev start   end deltastart base   p1   p2"
                  " rawsize totalsize compression heads chainlen\n"))
         ts = 0
         heads = set()
 
         for rev in pycompat.xrange(numrevs):
             dbase = r.deltaparent(rev)
             if dbase == -1:
                 dbase = rev
             cbase = r.chainbase(rev)
             clen = r.chainlen(rev)
             p1, p2 = r.parentrevs(rev)
             rs = r.rawsize(rev)
             ts = ts + rs
             heads -= set(r.parentrevs(rev))
             heads.add(rev)
             try:
                 compression = ts / r.end(rev)
             except ZeroDivisionError:
                 compression = 0
             ui.write("%5d %5d %5d %5d %5d %10d %4d %4d %4d %7d %9d "
                      "%11d %5d %8d\n" %
                      (rev, p1, p2, r.start(rev), r.end(rev),
                       r.start(dbase), r.start(cbase),
                       r.start(p1), r.start(p2),
                       rs, ts, compression, len(heads), clen))
         return 0
 
     v = r.version
     format = v & 0xFFFF
     flags = []
     gdelta = False
     if v & revlog.FLAG_INLINE_DATA:
         flags.append('inline')
     if v & revlog.FLAG_GENERALDELTA:
         gdelta = True
         flags.append('generaldelta')
     if not flags:
         flags = ['(none)']
 
     ### tracks merge vs single parent
     nummerges = 0
 
     ### tracks ways the "delta" are build
     # nodelta
     numempty = 0
     numemptytext = 0
     numemptydelta = 0
     # full file content
     numfull = 0
     # intermediate snapshot against a prior snapshot
     numsemi = 0
     # snapshot count per depth
     numsnapdepth = collections.defaultdict(lambda: 0)
     # delta against previous revision
     numprev = 0
     # delta against first or second parent (not prev)
     nump1 = 0
     nump2 = 0
     # delta against neither prev nor parents
     numother = 0
     # delta against prev that are also first or second parent
     # (details of `numprev`)
     nump1prev = 0
     nump2prev = 0
 
     # data about delta chain of each revs
     chainlengths = []
     chainbases = []
     chainspans = []
 
     # data about each revision
     datasize = [None, 0, 0]
     fullsize = [None, 0, 0]
     semisize = [None, 0, 0]
     # snapshot count per depth
     snapsizedepth = collections.defaultdict(lambda: [None, 0, 0])
     deltasize = [None, 0, 0]
     chunktypecounts = {}
     chunktypesizes = {}
 
     def addsize(size, l):
         if l[0] is None or size < l[0]:
             l[0] = size
         if size > l[1]:
             l[1] = size
         l[2] += size
 
     numrevs = len(r)
     for rev in pycompat.xrange(numrevs):
         p1, p2 = r.parentrevs(rev)
         delta = r.deltaparent(rev)
         if format > 0:
             addsize(r.rawsize(rev), datasize)
         if p2 != nullrev:
             nummerges += 1
         size = r.length(rev)
         if delta == nullrev:
             chainlengths.append(0)
             chainbases.append(r.start(rev))
             chainspans.append(size)
             if size == 0:
                 numempty += 1
                 numemptytext += 1
             else:
                 numfull += 1
                 numsnapdepth[0] += 1
                 addsize(size, fullsize)
                 addsize(size, snapsizedepth[0])
         else:
             chainlengths.append(chainlengths[delta] + 1)
             baseaddr = chainbases[delta]
             revaddr = r.start(rev)
             chainbases.append(baseaddr)
             chainspans.append((revaddr - baseaddr) + size)
             if size == 0:
                 numempty += 1
                 numemptydelta += 1
             elif r.issnapshot(rev):
                 addsize(size, semisize)
                 numsemi += 1
                 depth = r.snapshotdepth(rev)
                 numsnapdepth[depth] += 1
                 addsize(size, snapsizedepth[depth])
             else:
                 addsize(size, deltasize)
                 if delta == rev - 1:
                     numprev += 1
                     if delta == p1:
                         nump1prev += 1
                     elif delta == p2:
                         nump2prev += 1
                 elif delta == p1:
                     nump1 += 1
                 elif delta == p2:
                     nump2 += 1
                 elif delta != nullrev:
                     numother += 1
 
         # Obtain data on the raw chunks in the revlog.
         if util.safehasattr(r, '_getsegmentforrevs'):
             segment = r._getsegmentforrevs(rev, rev)[1]
         else:
             segment = r._revlog._getsegmentforrevs(rev, rev)[1]
         if segment:
             chunktype = bytes(segment[0:1])
         else:
             chunktype = 'empty'
 
         if chunktype not in chunktypecounts:
             chunktypecounts[chunktype] = 0
             chunktypesizes[chunktype] = 0
 
         chunktypecounts[chunktype] += 1
         chunktypesizes[chunktype] += size
 
     # Adjust size min value for empty cases
     for size in (datasize, fullsize, semisize, deltasize):
         if size[0] is None:
             size[0] = 0
 
     numdeltas = numrevs - numfull - numempty - numsemi
     numoprev = numprev - nump1prev - nump2prev
     totalrawsize = datasize[2]
     datasize[2] /= numrevs
     fulltotal = fullsize[2]
     fullsize[2] /= numfull
     semitotal = semisize[2]
     snaptotal = {}
     if numsemi > 0:
         semisize[2] /= numsemi
     for depth in snapsizedepth:
         snaptotal[depth] = snapsizedepth[depth][2]
         snapsizedepth[depth][2] /= numsnapdepth[depth]
 
     deltatotal = deltasize[2]
     if numdeltas > 0:
         deltasize[2] /= numdeltas
     totalsize = fulltotal + semitotal + deltatotal
     avgchainlen = sum(chainlengths) / numrevs
     maxchainlen = max(chainlengths)
     maxchainspan = max(chainspans)
     compratio = 1
     if totalsize:
         compratio = totalrawsize / totalsize
 
     basedfmtstr = '%%%dd\n'
     basepcfmtstr = '%%%dd %s(%%5.2f%%%%)\n'
 
     def dfmtstr(max):
         return basedfmtstr % len(str(max))
     def pcfmtstr(max, padding=0):
         return basepcfmtstr % (len(str(max)), ' ' * padding)
 
     def pcfmt(value, total):
         if total:
             return (value, 100 * float(value) / total)
         else:
             return value, 100.0
 
     ui.write(('format : %d\n') % format)
     ui.write(('flags  : %s\n') % ', '.join(flags))
 
     ui.write('\n')
     fmt = pcfmtstr(totalsize)
     fmt2 = dfmtstr(totalsize)
     ui.write(('revisions     : ') + fmt2 % numrevs)
     ui.write(('    merges    : ') + fmt % pcfmt(nummerges, numrevs))
     ui.write(('    normal    : ') + fmt % pcfmt(numrevs - nummerges, numrevs))
     ui.write(('revisions     : ') + fmt2 % numrevs)
     ui.write(('    empty     : ') + fmt % pcfmt(numempty, numrevs))
     ui.write(('                   text  : ')
              + fmt % pcfmt(numemptytext, numemptytext + numemptydelta))
     ui.write(('                   delta : ')
              + fmt % pcfmt(numemptydelta, numemptytext + numemptydelta))
     ui.write(('    snapshot  : ') + fmt % pcfmt(numfull + numsemi, numrevs))
     for depth in sorted(numsnapdepth):
         ui.write(('      lvl-%-3d :       ' % depth)
                  + fmt % pcfmt(numsnapdepth[depth], numrevs))
     ui.write(('    deltas    : ') + fmt % pcfmt(numdeltas, numrevs))
     ui.write(('revision size : ') + fmt2 % totalsize)
     ui.write(('    snapshot  : ')
              + fmt % pcfmt(fulltotal + semitotal, totalsize))
     for depth in sorted(numsnapdepth):
         ui.write(('      lvl-%-3d :       ' % depth)
                  + fmt % pcfmt(snaptotal[depth], totalsize))
     ui.write(('    deltas    : ') + fmt % pcfmt(deltatotal, totalsize))
 
     def fmtchunktype(chunktype):
         if chunktype == 'empty':
             return '    %s     : ' % chunktype
         elif chunktype in pycompat.bytestr(string.ascii_letters):
             return '    0x%s (%s)  : ' % (hex(chunktype), chunktype)
         else:
             return '    0x%s      : ' % hex(chunktype)
 
     ui.write('\n')
     ui.write(('chunks        : ') + fmt2 % numrevs)
     for chunktype in sorted(chunktypecounts):
         ui.write(fmtchunktype(chunktype))
         ui.write(fmt % pcfmt(chunktypecounts[chunktype], numrevs))
     ui.write(('chunks size   : ') + fmt2 % totalsize)
     for chunktype in sorted(chunktypecounts):
         ui.write(fmtchunktype(chunktype))
         ui.write(fmt % pcfmt(chunktypesizes[chunktype], totalsize))
 
     ui.write('\n')
     fmt = dfmtstr(max(avgchainlen, maxchainlen, maxchainspan, compratio))
     ui.write(('avg chain length  : ') + fmt % avgchainlen)
     ui.write(('max chain length  : ') + fmt % maxchainlen)
     ui.write(('max chain reach   : ') + fmt % maxchainspan)
     ui.write(('compression ratio : ') + fmt % compratio)
 
     if format > 0:
         ui.write('\n')
         ui.write(('uncompressed data size (min/max/avg) : %d / %d / %d\n')
                  % tuple(datasize))
     ui.write(('full revision size (min/max/avg)     : %d / %d / %d\n')
              % tuple(fullsize))
     ui.write(('inter-snapshot size (min/max/avg)    : %d / %d / %d\n')
              % tuple(semisize))
     for depth in sorted(snapsizedepth):
         if depth == 0:
             continue
         ui.write(('    level-%-3d (min/max/avg)          : %d / %d / %d\n')
                  % ((depth,) + tuple(snapsizedepth[depth])))
     ui.write(('delta size (min/max/avg)             : %d / %d / %d\n')
              % tuple(deltasize))
 
     if numdeltas > 0:
         ui.write('\n')
         fmt = pcfmtstr(numdeltas)
         fmt2 = pcfmtstr(numdeltas, 4)
         ui.write(('deltas against prev  : ') + fmt % pcfmt(numprev, numdeltas))
         if numprev > 0:
             ui.write(('    where prev = p1  : ') + fmt2 % pcfmt(nump1prev,
                                                               numprev))
             ui.write(('    where prev = p2  : ') + fmt2 % pcfmt(nump2prev,
                                                               numprev))
             ui.write(('    other            : ') + fmt2 % pcfmt(numoprev,
                                                               numprev))
         if gdelta:
             ui.write(('deltas against p1    : ')
                      + fmt % pcfmt(nump1, numdeltas))
             ui.write(('deltas against p2    : ')
                      + fmt % pcfmt(nump2, numdeltas))
             ui.write(('deltas against other : ') + fmt % pcfmt(numother,
                                                              numdeltas))
 
 @command('debugrevlogindex', cmdutil.debugrevlogopts +
     [('f', 'format', 0, _('revlog format'), _('FORMAT'))],
     _('[-f FORMAT] -c|-m|FILE'),
     optionalrepo=True)
 def debugrevlogindex(ui, repo, file_=None, **opts):
     """dump the contents of a revlog index"""
     opts = pycompat.byteskwargs(opts)
     r = cmdutil.openrevlog(repo, 'debugrevlogindex', file_, opts)
     format = opts.get('format', 0)
     if format not in (0, 1):
         raise error.Abort(_("unknown format %d") % format)
 
     if ui.debugflag:
         shortfn = hex
     else:
         shortfn = short
 
     # There might not be anything in r, so have a sane default
     idlen = 12
     for i in r:
         idlen = len(shortfn(r.node(i)))
         break
 
     if format == 0:
         if ui.verbose:
             ui.write(("   rev    offset  length linkrev"
                      " %s %s p2\n") % ("nodeid".ljust(idlen),
                                        "p1".ljust(idlen)))
         else:
             ui.write(("   rev linkrev %s %s p2\n") % (
                 "nodeid".ljust(idlen), "p1".ljust(idlen)))
     elif format == 1:
         if ui.verbose:
             ui.write(("   rev flag   offset   length     size   link     p1"
                       "     p2 %s\n") % "nodeid".rjust(idlen))
         else:
             ui.write(("   rev flag     size   link     p1     p2 %s\n") %
                      "nodeid".rjust(idlen))
 
     for i in r:
         node = r.node(i)
         if format == 0:
             try:
                 pp = r.parents(node)
             except Exception:
                 pp = [nullid, nullid]
             if ui.verbose:
                 ui.write("% 6d % 9d % 7d % 7d %s %s %s\n" % (
                         i, r.start(i), r.length(i), r.linkrev(i),
                         shortfn(node), shortfn(pp[0]), shortfn(pp[1])))
             else:
                 ui.write("% 6d % 7d %s %s %s\n" % (
                     i, r.linkrev(i), shortfn(node), shortfn(pp[0]),
                     shortfn(pp[1])))
         elif format == 1:
             pr = r.parentrevs(i)
             if ui.verbose:
                 ui.write("% 6d %04x % 8d % 8d % 8d % 6d % 6d % 6d %s\n" % (
                         i, r.flags(i), r.start(i), r.length(i), r.rawsize(i),
                         r.linkrev(i), pr[0], pr[1], shortfn(node)))
             else:
                 ui.write("% 6d %04x % 8d % 6d % 6d % 6d %s\n" % (
                     i, r.flags(i), r.rawsize(i), r.linkrev(i), pr[0], pr[1],
                     shortfn(node)))
 
 @command('debugrevspec',
     [('', 'optimize', None,
       _('print parsed tree after optimizing (DEPRECATED)')),
      ('', 'show-revs', True, _('print list of result revisions (default)')),
      ('s', 'show-set', None, _('print internal representation of result set')),
      ('p', 'show-stage', [],
       _('print parsed tree at the given stage'), _('NAME')),
      ('', 'no-optimized', False, _('evaluate tree without optimization')),
      ('', 'verify-optimized', False, _('verify optimized result')),
      ],
     ('REVSPEC'))
 def debugrevspec(ui, repo, expr, **opts):
     """parse and apply a revision specification
 
     Use -p/--show-stage option to print the parsed tree at the given stages.
     Use -p all to print tree at every stage.
 
     Use --no-show-revs option with -s or -p to print only the set
     representation or the parsed tree respectively.
 
     Use --verify-optimized to compare the optimized result with the unoptimized
     one. Returns 1 if the optimized result differs.
     """
     opts = pycompat.byteskwargs(opts)
     aliases = ui.configitems('revsetalias')
     stages = [
         ('parsed', lambda tree: tree),
         ('expanded', lambda tree: revsetlang.expandaliases(tree, aliases,
                                                            ui.warn)),
         ('concatenated', revsetlang.foldconcat),
         ('analyzed', revsetlang.analyze),
         ('optimized', revsetlang.optimize),
     ]
     if opts['no_optimized']:
         stages = stages[:-1]
     if opts['verify_optimized'] and opts['no_optimized']:
         raise error.Abort(_('cannot use --verify-optimized with '
                             '--no-optimized'))
     stagenames = set(n for n, f in stages)
 
     showalways = set()
     showchanged = set()
     if ui.verbose and not opts['show_stage']:
         # show parsed tree by --verbose (deprecated)
         showalways.add('parsed')
         showchanged.update(['expanded', 'concatenated'])
         if opts['optimize']:
             showalways.add('optimized')
     if opts['show_stage'] and opts['optimize']:
         raise error.Abort(_('cannot use --optimize with --show-stage'))
     if opts['show_stage'] == ['all']:
         showalways.update(stagenames)
     else:
         for n in opts['show_stage']:
             if n not in stagenames:
                 raise error.Abort(_('invalid stage name: %s') % n)
         showalways.update(opts['show_stage'])
 
     treebystage = {}
     printedtree = None
     tree = revsetlang.parse(expr, lookup=revset.lookupfn(repo))
     for n, f in stages:
         treebystage[n] = tree = f(tree)
         if n in showalways or (n in showchanged and tree != printedtree):
             if opts['show_stage'] or n != 'parsed':
                 ui.write(("* %s:\n") % n)
             ui.write(revsetlang.prettyformat(tree), "\n")
             printedtree = tree
 
     if opts['verify_optimized']:
         arevs = revset.makematcher(treebystage['analyzed'])(repo)
         brevs = revset.makematcher(treebystage['optimized'])(repo)
         if opts['show_set'] or (opts['show_set'] is None and ui.verbose):
             ui.write(("* analyzed set:\n"), stringutil.prettyrepr(arevs), "\n")
             ui.write(("* optimized set:\n"), stringutil.prettyrepr(brevs), "\n")
         arevs = list(arevs)
         brevs = list(brevs)
         if arevs == brevs:
             return 0
         ui.write(('--- analyzed\n'), label='diff.file_a')
         ui.write(('+++ optimized\n'), label='diff.file_b')
         sm = difflib.SequenceMatcher(None, arevs, brevs)
         for tag, alo, ahi, blo, bhi in sm.get_opcodes():
             if tag in (r'delete', r'replace'):
                 for c in arevs[alo:ahi]:
                     ui.write('-%d\n' % c, label='diff.deleted')
             if tag in (r'insert', r'replace'):
                 for c in brevs[blo:bhi]:
                     ui.write('+%d\n' % c, label='diff.inserted')
             if tag == r'equal':
                 for c in arevs[alo:ahi]:
                     ui.write(' %d\n' % c)
         return 1
 
     func = revset.makematcher(tree)
     revs = func(repo)
     if opts['show_set'] or (opts['show_set'] is None and ui.verbose):
         ui.write(("* set:\n"), stringutil.prettyrepr(revs), "\n")
     if not opts['show_revs']:
         return
     for c in revs:
         ui.write("%d\n" % c)
 
 @command('debugserve', [
     ('', 'sshstdio', False, _('run an SSH server bound to process handles')),
     ('', 'logiofd', '', _('file descriptor to log server I/O to')),
     ('', 'logiofile', '', _('file to log server I/O to')),
 ], '')
 def debugserve(ui, repo, **opts):
     """run a server with advanced settings
 
     This command is similar to :hg:`serve`. It exists partially as a
     workaround to the fact that ``hg serve --stdio`` must have specific
     arguments for security reasons.
     """
     opts = pycompat.byteskwargs(opts)
 
     if not opts['sshstdio']:
         raise error.Abort(_('only --sshstdio is currently supported'))
 
     logfh = None
 
     if opts['logiofd'] and opts['logiofile']:
         raise error.Abort(_('cannot use both --logiofd and --logiofile'))
 
     if opts['logiofd']:
         # Line buffered because output is line based.
         try:
             logfh = os.fdopen(int(opts['logiofd']), r'ab', 1)
         except OSError as e:
             if e.errno != errno.ESPIPE:
                 raise
             # can't seek a pipe, so `ab` mode fails on py3
             logfh = os.fdopen(int(opts['logiofd']), r'wb', 1)
     elif opts['logiofile']:
         logfh = open(opts['logiofile'], 'ab', 1)
 
     s = wireprotoserver.sshserver(ui, repo, logfh=logfh)
     s.serve_forever()
 
 @command('debugsetparents', [], _('REV1 [REV2]'))
 def debugsetparents(ui, repo, rev1, rev2=None):
     """manually set the parents of the current working directory
 
     This is useful for writing repository conversion tools, but should
     be used with care. For example, neither the working directory nor the
     dirstate is updated, so file status may be incorrect after running this
     command.
 
     Returns 0 on success.
     """
 
     node1 = scmutil.revsingle(repo, rev1).node()
     node2 = scmutil.revsingle(repo, rev2, 'null').node()
 
     with repo.wlock():
         repo.setparents(node1, node2)
 
 @command('debugssl', [], '[SOURCE]', optionalrepo=True)
 def debugssl(ui, repo, source=None, **opts):
     '''test a secure connection to a server
 
     This builds the certificate chain for the server on Windows, installing the
     missing intermediates and trusted root via Windows Update if necessary.  It
     does nothing on other platforms.
 
     If SOURCE is omitted, the 'default' path will be used.  If a URL is given,
     that server is used. See :hg:`help urls` for more information.
 
     If the update succeeds, retry the original operation.  Otherwise, the cause
     of the SSL error is likely another issue.
     '''
     if not pycompat.iswindows:
         raise error.Abort(_('certificate chain building is only possible on '
                             'Windows'))
 
     if not source:
         if not repo:
             raise error.Abort(_("there is no Mercurial repository here, and no "
                                 "server specified"))
         source = "default"
 
     source, branches = hg.parseurl(ui.expandpath(source))
     url = util.url(source)
 
     defaultport = {'https': 443, 'ssh': 22}
     if url.scheme in defaultport:
         try:
             addr = (url.host, int(url.port or defaultport[url.scheme]))
         except ValueError:
             raise error.Abort(_("malformed port number in URL"))
     else:
         raise error.Abort(_("only https and ssh connections are supported"))
 
     from . import win32
 
     s = ssl.wrap_socket(socket.socket(), ssl_version=ssl.PROTOCOL_TLS,
                         cert_reqs=ssl.CERT_NONE, ca_certs=None)
 
     try:
         s.connect(addr)
         cert = s.getpeercert(True)
 
         ui.status(_('checking the certificate chain for %s\n') % url.host)
 
         complete = win32.checkcertificatechain(cert, build=False)
 
         if not complete:
             ui.status(_('certificate chain is incomplete, updating... '))
 
             if not win32.checkcertificatechain(cert):
                 ui.status(_('failed.\n'))
             else:
                 ui.status(_('done.\n'))
         else:
             ui.status(_('full certificate chain is available\n'))
     finally:
         s.close()
 
 @command('debugsub',
     [('r', 'rev', '',
      _('revision to check'), _('REV'))],
     _('[-r REV] [REV]'))
 def debugsub(ui, repo, rev=None):
     ctx = scmutil.revsingle(repo, rev, None)
     for k, v in sorted(ctx.substate.items()):
         ui.write(('path %s\n') % k)
         ui.write((' source   %s\n') % v[0])
         ui.write((' revision %s\n') % v[1])
 
 @command('debugsuccessorssets',
     [('', 'closest', False, _('return closest successors sets only'))],
     _('[REV]'))
 def debugsuccessorssets(ui, repo, *revs, **opts):
     """show set of successors for revision
 
     A successors set of changeset A is a consistent group of revisions that
     succeed A. It contains non-obsolete changesets only unless closests
     successors set is set.
 
     In most cases a changeset A has a single successors set containing a single
     successor (changeset A replaced by A').
 
     A changeset that is made obsolete with no successors are called "pruned".
     Such changesets have no successors sets at all.
 
     A changeset that has been "split" will have a successors set containing
     more than one successor.
 
     A changeset that has been rewritten in multiple different ways is called
     "divergent". Such changesets have multiple successor sets (each of which
     may also be split, i.e. have multiple successors).
 
     Results are displayed as follows::
 
         <rev1>
             <successors-1A>
         <rev2>
             <successors-2A>
             <successors-2B1> <successors-2B2> <successors-2B3>
 
     Here rev2 has two possible (i.e. divergent) successors sets. The first
     holds one element, whereas the second holds three (i.e. the changeset has
     been split).
     """
     # passed to successorssets caching computation from one call to another
     cache = {}
     ctx2str = bytes
     node2str = short
     for rev in scmutil.revrange(repo, revs):
         ctx = repo[rev]
         ui.write('%s\n'% ctx2str(ctx))
         for succsset in obsutil.successorssets(repo, ctx.node(),
                                                 closest=opts[r'closest'],
                                                 cache=cache):
             if succsset:
                 ui.write('    ')
                 ui.write(node2str(succsset[0]))
                 for node in succsset[1:]:
                     ui.write(' ')
                     ui.write(node2str(node))
             ui.write('\n')
 
 @command('debugtemplate',
     [('r', 'rev', [], _('apply template on changesets'), _('REV')),
      ('D', 'define', [], _('define template keyword'), _('KEY=VALUE'))],
     _('[-r REV]... [-D KEY=VALUE]... TEMPLATE'),
     optionalrepo=True)
 def debugtemplate(ui, repo, tmpl, **opts):
     """parse and apply a template
 
     If -r/--rev is given, the template is processed as a log template and
     applied to the given changesets. Otherwise, it is processed as a generic
     template.
 
     Use --verbose to print the parsed tree.
     """
     revs = None
     if opts[r'rev']:
         if repo is None:
             raise error.RepoError(_('there is no Mercurial repository here '
                                     '(.hg not found)'))
         revs = scmutil.revrange(repo, opts[r'rev'])
 
     props = {}
     for d in opts[r'define']:
         try:
             k, v = (e.strip() for e in d.split('=', 1))
             if not k or k == 'ui':
                 raise ValueError
             props[k] = v
         except ValueError:
             raise error.Abort(_('malformed keyword definition: %s') % d)
 
     if ui.verbose:
         aliases = ui.configitems('templatealias')
         tree = templater.parse(tmpl)
         ui.note(templater.prettyformat(tree), '\n')
         newtree = templater.expandaliases(tree, aliases)
         if newtree != tree:
             ui.note(("* expanded:\n"), templater.prettyformat(newtree), '\n')
 
     if revs is None:
         tres = formatter.templateresources(ui, repo)
         t = formatter.maketemplater(ui, tmpl, resources=tres)
         if ui.verbose:
             kwds, funcs = t.symbolsuseddefault()
             ui.write(("* keywords: %s\n") % ', '.join(sorted(kwds)))
             ui.write(("* functions: %s\n") % ', '.join(sorted(funcs)))
         ui.write(t.renderdefault(props))
     else:
         displayer = logcmdutil.maketemplater(ui, repo, tmpl)
         if ui.verbose:
             kwds, funcs = displayer.t.symbolsuseddefault()
             ui.write(("* keywords: %s\n") % ', '.join(sorted(kwds)))
             ui.write(("* functions: %s\n") % ', '.join(sorted(funcs)))
         for r in revs:
             displayer.show(repo[r], **pycompat.strkwargs(props))
         displayer.close()
 
 @command('debuguigetpass', [
     ('p', 'prompt', '', _('prompt text'), _('TEXT')),
 ], _('[-p TEXT]'), norepo=True)
 def debuguigetpass(ui, prompt=''):
     """show prompt to type password"""
     r = ui.getpass(prompt)
     ui.write(('respose: %s\n') % r)
 
 @command('debuguiprompt', [
     ('p', 'prompt', '', _('prompt text'), _('TEXT')),
 ], _('[-p TEXT]'), norepo=True)
 def debuguiprompt(ui, prompt=''):
     """show plain prompt"""
     r = ui.prompt(prompt)
     ui.write(('response: %s\n') % r)
 
 @command('debugupdatecaches', [])
 def debugupdatecaches(ui, repo, *pats, **opts):
     """warm all known caches in the repository"""
     with repo.wlock(), repo.lock():
         repo.updatecaches(full=True)
 
 @command('debugupgraderepo', [
     ('o', 'optimize', [], _('extra optimization to perform'), _('NAME')),
     ('', 'run', False, _('performs an upgrade')),
     ('', 'backup', True, _('keep the old repository content around')),
 ])
 def debugupgraderepo(ui, repo, run=False, optimize=None, backup=True):
     """upgrade a repository to use different features
 
     If no arguments are specified, the repository is evaluated for upgrade
     and a list of problems and potential optimizations is printed.
 
     With ``--run``, a repository upgrade is performed. Behavior of the upgrade
     can be influenced via additional arguments. More details will be provided
     by the command output when run without ``--run``.
 
     During the upgrade, the repository will be locked and no writes will be
     allowed.
 
     At the end of the upgrade, the repository may not be readable while new
     repository data is swapped in. This window will be as long as it takes to
     rename some directories inside the ``.hg`` directory. On most machines, this
     should complete almost instantaneously and the chances of a consumer being
     unable to access the repository should be low.
     """
     return upgrade.upgraderepo(ui, repo, run=run, optimize=optimize,
                                backup=backup)
 
 @command('debugwalk', cmdutil.walkopts, _('[OPTION]... [FILE]...'),
          inferrepo=True)
 def debugwalk(ui, repo, *pats, **opts):
     """show how files match on given patterns"""
     opts = pycompat.byteskwargs(opts)
     m = scmutil.match(repo[None], pats, opts)
     if ui.verbose:
         ui.write(('* matcher:\n'), stringutil.prettyrepr(m), '\n')
     items = list(repo[None].walk(m))
     if not items:
         return
     f = lambda fn: fn
     if ui.configbool('ui', 'slash') and pycompat.ossep != '/':
         f = lambda fn: util.normpath(fn)
     fmt = 'f  %%-%ds  %%-%ds  %%s' % (
         max([len(abs) for abs in items]),
         max([len(repo.pathto(abs)) for abs in items]))
     for abs in items:
         line = fmt % (abs, f(repo.pathto(abs)), m.exact(abs) and 'exact' or '')
         ui.write("%s\n" % line.rstrip())
 
 @command('debugwhyunstable', [], _('REV'))
 def debugwhyunstable(ui, repo, rev):
     """explain instabilities of a changeset"""
     for entry in obsutil.whyunstable(repo, scmutil.revsingle(repo, rev)):
         dnodes = ''
         if entry.get('divergentnodes'):
             dnodes = ' '.join('%s (%s)' % (ctx.hex(), ctx.phasestr())
                               for ctx in entry['divergentnodes']) + ' '
         ui.write('%s: %s%s %s\n' % (entry['instability'], dnodes,
                                     entry['reason'], entry['node']))
 
 @command('debugwireargs',
     [('', 'three', '', 'three'),
     ('', 'four', '', 'four'),
     ('', 'five', '', 'five'),
     ] + cmdutil.remoteopts,
     _('REPO [OPTIONS]... [ONE [TWO]]'),
     norepo=True)
 def debugwireargs(ui, repopath, *vals, **opts):
     opts = pycompat.byteskwargs(opts)
     repo = hg.peer(ui, opts, repopath)
     for opt in cmdutil.remoteopts:
         del opts[opt[1]]
     args = {}
     for k, v in opts.iteritems():
         if v:
             args[k] = v
     args = pycompat.strkwargs(args)
     # run twice to check that we don't mess up the stream for the next command
     res1 = repo.debugwireargs(*vals, **args)
     res2 = repo.debugwireargs(*vals, **args)
     ui.write("%s\n" % res1)
     if res1 != res2:
         ui.warn("%s\n" % res2)
 
 def _parsewirelangblocks(fh):
     activeaction = None
     blocklines = []
     lastindent = 0
 
     for line in fh:
         line = line.rstrip()
         if not line:
             continue
 
         if line.startswith(b'#'):
             continue
 
         if not line.startswith(b' '):
             # New block. Flush previous one.
             if activeaction:
                 yield activeaction, blocklines
 
             activeaction = line
             blocklines = []
             lastindent = 0
             continue
 
         # Else we start with an indent.
 
         if not activeaction:
             raise error.Abort(_('indented line outside of block'))
 
         indent = len(line) - len(line.lstrip())
 
         # If this line is indented more than the last line, concatenate it.
         if indent > lastindent and blocklines:
             blocklines[-1] += line.lstrip()
         else:
             blocklines.append(line)
             lastindent = indent
 
     # Flush last block.
     if activeaction:
         yield activeaction, blocklines
 
 @command('debugwireproto',
     [
         ('', 'localssh', False, _('start an SSH server for this repo')),
         ('', 'peer', '', _('construct a specific version of the peer')),
         ('', 'noreadstderr', False, _('do not read from stderr of the remote')),
         ('', 'nologhandshake', False,
          _('do not log I/O related to the peer handshake')),
     ] + cmdutil.remoteopts,
     _('[PATH]'),
     optionalrepo=True)
 def debugwireproto(ui, repo, path=None, **opts):
     """send wire protocol commands to a server
 
     This command can be used to issue wire protocol commands to remote
     peers and to debug the raw data being exchanged.
 
     ``--localssh`` will start an SSH server against the current repository
     and connect to that. By default, the connection will perform a handshake
     and establish an appropriate peer instance.
 
     ``--peer`` can be used to bypass the handshake protocol and construct a
     peer instance using the specified class type. Valid values are ``raw``,
     ``http2``, ``ssh1``, and ``ssh2``. ``raw`` instances only allow sending
     raw data payloads and don't support higher-level command actions.
 
     ``--noreadstderr`` can be used to disable automatic reading from stderr
     of the peer (for SSH connections only). Disabling automatic reading of
     stderr is useful for making output more deterministic.
 
     Commands are issued via a mini language which is specified via stdin.
     The language consists of individual actions to perform. An action is
     defined by a block. A block is defined as a line with no leading
     space followed by 0 or more lines with leading space. Blocks are
     effectively a high-level command with additional metadata.
 
     Lines beginning with ``#`` are ignored.
 
     The following sections denote available actions.
 
     raw
     ---
 
     Send raw data to the server.
 
     The block payload contains the raw data to send as one atomic send
     operation. The data may not actually be delivered in a single system
     call: it depends on the abilities of the transport being used.
 
     Each line in the block is de-indented and concatenated. Then, that
     value is evaluated as a Python b'' literal. This allows the use of
     backslash escaping, etc.
 
     raw+
     ----
 
     Behaves like ``raw`` except flushes output afterwards.
 
     command <X>
     -----------
 
     Send a request to run a named command, whose name follows the ``command``
     string.
 
     Arguments to the command are defined as lines in this block. The format of
     each line is ``<key> <value>``. e.g.::
 
        command listkeys
            namespace bookmarks
 
     If the value begins with ``eval:``, it will be interpreted as a Python
     literal expression. Otherwise values are interpreted as Python b'' literals.
     This allows sending complex types and encoding special byte sequences via
     backslash escaping.
 
     The following arguments have special meaning:
 
     ``PUSHFILE``
         When defined, the *push* mechanism of the peer will be used instead
         of the static request-response mechanism and the content of the
         file specified in the value of this argument will be sent as the
         command payload.
 
         This can be used to submit a local bundle file to the remote.
 
     batchbegin
     ----------
 
     Instruct the peer to begin a batched send.
 
     All ``command`` blocks are queued for execution until the next
     ``batchsubmit`` block.
 
     batchsubmit
     -----------
 
     Submit previously queued ``command`` blocks as a batch request.
 
     This action MUST be paired with a ``batchbegin`` action.
 
     httprequest <method> <path>
     ---------------------------
 
     (HTTP peer only)
 
     Send an HTTP request to the peer.
 
     The HTTP request line follows the ``httprequest`` action. e.g. ``GET /foo``.
 
     Arguments of the form ``<key>: <value>`` are interpreted as HTTP request
     headers to add to the request. e.g. ``Accept: foo``.
 
     The following arguments are special:
 
     ``BODYFILE``
         The content of the file defined as the value to this argument will be
         transferred verbatim as the HTTP request body.
 
     ``frame <type> <flags> <payload>``
         Send a unified protocol frame as part of the request body.
 
         All frames will be collected and sent as the body to the HTTP
         request.
 
     close
     -----
 
     Close the connection to the server.
 
     flush
     -----
 
     Flush data written to the server.
 
     readavailable
     -------------
 
     Close the write end of the connection and read all available data from
     the server.
 
     If the connection to the server encompasses multiple pipes, we poll both
     pipes and read available data.
 
     readline
     --------
 
     Read a line of output from the server. If there are multiple output
     pipes, reads only the main pipe.
 
     ereadline
     ---------
 
     Like ``readline``, but read from the stderr pipe, if available.
 
     read <X>
     --------
 
     ``read()`` N bytes from the server's main output pipe.
 
     eread <X>
     ---------
 
     ``read()`` N bytes from the server's stderr pipe, if available.
 
     Specifying Unified Frame-Based Protocol Frames
     ----------------------------------------------
 
     It is possible to emit a *Unified Frame-Based Protocol* by using special
     syntax.
 
     A frame is composed as a type, flags, and payload. These can be parsed
     from a string of the form:
 
        <request-id> <stream-id> <stream-flags> <type> <flags> <payload>
 
     ``request-id`` and ``stream-id`` are integers defining the request and
     stream identifiers.
 
     ``type`` can be an integer value for the frame type or the string name
     of the type. The strings are defined in ``wireprotoframing.py``. e.g.
     ``command-name``.
 
     ``stream-flags`` and ``flags`` are a ``|`` delimited list of flag
     components. Each component (and there can be just one) can be an integer
     or a flag name for stream flags or frame flags, respectively. Values are
     resolved to integers and then bitwise OR'd together.
 
     ``payload`` represents the raw frame payload. If it begins with
     ``cbor:``, the following string is evaluated as Python code and the
     resulting object is fed into a CBOR encoder. Otherwise it is interpreted
     as a Python byte string literal.
     """
     opts = pycompat.byteskwargs(opts)
 
     if opts['localssh'] and not repo:
         raise error.Abort(_('--localssh requires a repository'))
 
     if opts['peer'] and opts['peer'] not in ('raw', 'http2', 'ssh1', 'ssh2'):
         raise error.Abort(_('invalid value for --peer'),
                           hint=_('valid values are "raw", "ssh1", and "ssh2"'))
 
     if path and opts['localssh']:
         raise error.Abort(_('cannot specify --localssh with an explicit '
                             'path'))
 
     if ui.interactive():
         ui.write(_('(waiting for commands on stdin)\n'))
 
     blocks = list(_parsewirelangblocks(ui.fin))
 
     proc = None
     stdin = None
     stdout = None
     stderr = None
     opener = None
 
     if opts['localssh']:
         # We start the SSH server in its own process so there is process
         # separation. This prevents a whole class of potential bugs around
         # shared state from interfering with server operation.
         args = procutil.hgcmd() + [
             '-R', repo.root,
             'debugserve', '--sshstdio',
         ]
         proc = subprocess.Popen(pycompat.rapply(procutil.tonativestr, args),
                                 stdin=subprocess.PIPE,
                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                                 bufsize=0)
 
         stdin = proc.stdin
         stdout = proc.stdout
         stderr = proc.stderr
 
         # We turn the pipes into observers so we can log I/O.
         if ui.verbose or opts['peer'] == 'raw':
             stdin = util.makeloggingfileobject(ui, proc.stdin, b'i',
                                                logdata=True)
             stdout = util.makeloggingfileobject(ui, proc.stdout, b'o',
                                                 logdata=True)
             stderr = util.makeloggingfileobject(ui, proc.stderr, b'e',
                                                 logdata=True)
 
         # --localssh also implies the peer connection settings.
 
         url = 'ssh://localserver'
         autoreadstderr = not opts['noreadstderr']
 
         if opts['peer'] == 'ssh1':
             ui.write(_('creating ssh peer for wire protocol version 1\n'))
             peer = sshpeer.sshv1peer(ui, url, proc, stdin, stdout, stderr,
                                      None, autoreadstderr=autoreadstderr)
         elif opts['peer'] == 'ssh2':
             ui.write(_('creating ssh peer for wire protocol version 2\n'))
             peer = sshpeer.sshv2peer(ui, url, proc, stdin, stdout, stderr,
                                      None, autoreadstderr=autoreadstderr)
         elif opts['peer'] == 'raw':
             ui.write(_('using raw connection to peer\n'))
             peer = None
         else:
             ui.write(_('creating ssh peer from handshake results\n'))
             peer = sshpeer.makepeer(ui, url, proc, stdin, stdout, stderr,
                                     autoreadstderr=autoreadstderr)
 
     elif path:
         # We bypass hg.peer() so we can proxy the sockets.
         # TODO consider not doing this because we skip
         # ``hg.wirepeersetupfuncs`` and potentially other useful functionality.
         u = util.url(path)
         if u.scheme != 'http':
             raise error.Abort(_('only http:// paths are currently supported'))
 
         url, authinfo = u.authinfo()
         openerargs = {
             r'useragent': b'Mercurial debugwireproto',
         }
 
         # Turn pipes/sockets into observers so we can log I/O.
         if ui.verbose:
             openerargs.update({
                 r'loggingfh': ui,
                 r'loggingname': b's',
                 r'loggingopts': {
                     r'logdata': True,
                     r'logdataapis': False,
                 },
             })
 
         if ui.debugflag:
             openerargs[r'loggingopts'][r'logdataapis'] = True
 
         # Don't send default headers when in raw mode. This allows us to
         # bypass most of the behavior of our URL handling code so we can
         # have near complete control over what's sent on the wire.
         if opts['peer'] == 'raw':
             openerargs[r'sendaccept'] = False
 
         opener = urlmod.opener(ui, authinfo, **openerargs)
 
         if opts['peer'] == 'http2':
             ui.write(_('creating http peer for wire protocol version 2\n'))
             # We go through makepeer() because we need an API descriptor for
             # the peer instance to be useful.
             with ui.configoverride({
                 ('experimental', 'httppeer.advertise-v2'): True}):
                 if opts['nologhandshake']:
                     ui.pushbuffer()
 
                 peer = httppeer.makepeer(ui, path, opener=opener)
 
                 if opts['nologhandshake']:
                     ui.popbuffer()
 
             if not isinstance(peer, httppeer.httpv2peer):
                 raise error.Abort(_('could not instantiate HTTP peer for '
                                     'wire protocol version 2'),
                                   hint=_('the server may not have the feature '
                                          'enabled or is not allowing this '
                                          'client version'))
 
         elif opts['peer'] == 'raw':
             ui.write(_('using raw connection to peer\n'))
             peer = None
         elif opts['peer']:
             raise error.Abort(_('--peer %s not supported with HTTP peers') %
                               opts['peer'])
         else:
             peer = httppeer.makepeer(ui, path, opener=opener)
 
         # We /could/ populate stdin/stdout with sock.makefile()...
     else:
         raise error.Abort(_('unsupported connection configuration'))
 
     batchedcommands = None
 
     # Now perform actions based on the parsed wire language instructions.
     for action, lines in blocks:
         if action in ('raw', 'raw+'):
             if not stdin:
                 raise error.Abort(_('cannot call raw/raw+ on this peer'))
 
             # Concatenate the data together.
             data = ''.join(l.lstrip() for l in lines)
             data = stringutil.unescapestr(data)
             stdin.write(data)
 
             if action == 'raw+':
                 stdin.flush()
         elif action == 'flush':
             if not stdin:
                 raise error.Abort(_('cannot call flush on this peer'))
             stdin.flush()
         elif action.startswith('command'):
             if not peer:
                 raise error.Abort(_('cannot send commands unless peer instance '
                                     'is available'))
 
             command = action.split(' ', 1)[1]
 
             args = {}
             for line in lines:
                 # We need to allow empty values.
                 fields = line.lstrip().split(' ', 1)
                 if len(fields) == 1:
                     key = fields[0]
                     value = ''
                 else:
                     key, value = fields
 
                 if value.startswith('eval:'):
                     value = stringutil.evalpythonliteral(value[5:])
                 else:
                     value = stringutil.unescapestr(value)
 
                 args[key] = value
 
             if batchedcommands is not None:
                 batchedcommands.append((command, args))
                 continue
 
             ui.status(_('sending %s command\n') % command)
 
             if 'PUSHFILE' in args:
                 with open(args['PUSHFILE'], r'rb') as fh:
                     del args['PUSHFILE']
                     res, output = peer._callpush(command, fh,
                                                  **pycompat.strkwargs(args))
                     ui.status(_('result: %s\n') % stringutil.escapestr(res))
                     ui.status(_('remote output: %s\n') %
                               stringutil.escapestr(output))
             else:
                 with peer.commandexecutor() as e:
                     res = e.callcommand(command, args).result()
 
                 if isinstance(res, wireprotov2peer.commandresponse):
                     val = res.objects()
                     ui.status(_('response: %s\n') %
                               stringutil.pprint(val, bprefix=True, indent=2))
                 else:
                     ui.status(_('response: %s\n') %
                               stringutil.pprint(res, bprefix=True, indent=2))
 
         elif action == 'batchbegin':
             if batchedcommands is not None:
                 raise error.Abort(_('nested batchbegin not allowed'))
 
             batchedcommands = []
         elif action == 'batchsubmit':
             # There is a batching API we could go through. But it would be
             # difficult to normalize requests into function calls. It is easier
             # to bypass this layer and normalize to commands + args.
             ui.status(_('sending batch with %d sub-commands\n') %
                       len(batchedcommands))
             for i, chunk in enumerate(peer._submitbatch(batchedcommands)):
                 ui.status(_('response #%d: %s\n') %
                           (i, stringutil.escapestr(chunk)))
 
             batchedcommands = None
 
         elif action.startswith('httprequest '):
             if not opener:
                 raise error.Abort(_('cannot use httprequest without an HTTP '
                                     'peer'))
 
             request = action.split(' ', 2)
             if len(request) != 3:
                 raise error.Abort(_('invalid httprequest: expected format is '
                                     '"httprequest <method> <path>'))
 
             method, httppath = request[1:]
             headers = {}
             body = None
             frames = []
             for line in lines:
                 line = line.lstrip()
                 m = re.match(b'^([a-zA-Z0-9_-]+): (.*)$', line)
                 if m:
                     # Headers need to use native strings.
                     key = pycompat.strurl(m.group(1))
                     value = pycompat.strurl(m.group(2))
                     headers[key] = value
                     continue
 
                 if line.startswith(b'BODYFILE '):
                     with open(line.split(b' ', 1), 'rb') as fh:
                         body = fh.read()
                 elif line.startswith(b'frame '):
                     frame = wireprotoframing.makeframefromhumanstring(
                         line[len(b'frame '):])
 
                     frames.append(frame)
                 else:
                     raise error.Abort(_('unknown argument to httprequest: %s') %
                                       line)
 
             url = path + httppath
 
             if frames:
                 body = b''.join(bytes(f) for f in frames)
 
             req = urlmod.urlreq.request(pycompat.strurl(url), body, headers)
 
             # urllib.Request insists on using has_data() as a proxy for
             # determining the request method. Override that to use our
             # explicitly requested method.
             req.get_method = lambda: pycompat.sysstr(method)
 
             try:
                 res = opener.open(req)
                 body = res.read()
             except util.urlerr.urlerror as e:
                 # read() method must be called, but only exists in Python 2
                 getattr(e, 'read', lambda: None)()
                 continue
 
             ct = res.headers.get(r'Content-Type')
             if ct == r'application/mercurial-cbor':
                 ui.write(_('cbor> %s\n') %
                          stringutil.pprint(cborutil.decodeall(body),
                                            bprefix=True,
                                            indent=2))
 
         elif action == 'close':
             peer.close()
         elif action == 'readavailable':
             if not stdout or not stderr:
                 raise error.Abort(_('readavailable not available on this peer'))
 
             stdin.close()
             stdout.read()
             stderr.read()
 
         elif action == 'readline':
             if not stdout:
                 raise error.Abort(_('readline not available on this peer'))
             stdout.readline()
         elif action == 'ereadline':
             if not stderr:
                 raise error.Abort(_('ereadline not available on this peer'))
             stderr.readline()
         elif action.startswith('read '):
             count = int(action.split(' ', 1)[1])
             if not stdout:
                 raise error.Abort(_('read not available on this peer'))
             stdout.read(count)
         elif action.startswith('eread '):
             count = int(action.split(' ', 1)[1])
             if not stderr:
                 raise error.Abort(_('eread not available on this peer'))
             stderr.read(count)
         else:
             raise error.Abort(_('unknown action: %s') % action)
 
     if batchedcommands is not None:
         raise error.Abort(_('unclosed "batchbegin" request'))
 
     if peer:
         peer.close()
 
     if proc:
         proc.kill()

mercurial/policy.py

@@ -1,109 +1,146 b''
 # policy.py - module policy logic for Mercurial.
 #
 # Copyright 2015 Gregory Szorc <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import os
 import sys
 
 # Rules for how modules can be loaded. Values are:
 #
 #    c - require C extensions
+#    rust+c - require Rust and C extensions
+#    rust+c-allow - allow Rust and C extensions with fallback to pure Python
+#                   for each
 #    allow - allow pure Python implementation when C loading fails
 #    cffi - required cffi versions (implemented within pure module)
 #    cffi-allow - allow pure Python implementation if cffi version is missing
 #    py - only load pure Python modules
 #
 # By default, fall back to the pure modules so the in-place build can
 # run without recompiling the C extensions. This will be overridden by
 # __modulepolicy__ generated by setup.py.
 policy = b'allow'
 _packageprefs = {
     # policy: (versioned package, pure package)
     b'c': (r'cext', None),
     b'allow': (r'cext', r'pure'),
     b'cffi': (r'cffi', None),
     b'cffi-allow': (r'cffi', r'pure'),
     b'py': (None, r'pure'),
+    # For now, rust policies impact importrust only
+    b'rust+c': (r'cext', None),
+    b'rust+c-allow': (r'cext', r'pure'),
 }
 
 try:
     from . import __modulepolicy__
     policy = __modulepolicy__.modulepolicy
 except ImportError:
     pass
 
 # PyPy doesn't load C extensions.
 #
 # The canonical way to do this is to test platform.python_implementation().
 # But we don't import platform and don't bloat for it here.
 if r'__pypy__' in sys.builtin_module_names:
     policy = b'cffi'
 
 # Environment variable can always force settings.
 if sys.version_info[0] >= 3:
     if r'HGMODULEPOLICY' in os.environ:
         policy = os.environ[r'HGMODULEPOLICY'].encode(r'utf-8')
 else:
     policy = os.environ.get(r'HGMODULEPOLICY', policy)
 
 def _importfrom(pkgname, modname):
     # from .<pkgname> import <modname> (where . is looked through this module)
     fakelocals = {}
     pkg = __import__(pkgname, globals(), fakelocals, [modname], level=1)
     try:
         fakelocals[modname] = mod = getattr(pkg, modname)
     except AttributeError:
         raise ImportError(r'cannot import name %s' % modname)
     # force import; fakelocals[modname] may be replaced with the real module
     getattr(mod, r'__doc__', None)
     return fakelocals[modname]
 
 # keep in sync with "version" in C modules
 _cextversions = {
     (r'cext', r'base85'): 1,
     (r'cext', r'bdiff'): 3,
     (r'cext', r'mpatch'): 1,
     (r'cext', r'osutil'): 4,
     (r'cext', r'parsers'): 13,
 }
 
 # map import request to other package or module
 _modredirects = {
     (r'cext', r'charencode'): (r'cext', r'parsers'),
     (r'cffi', r'base85'): (r'pure', r'base85'),
     (r'cffi', r'charencode'): (r'pure', r'charencode'),
     (r'cffi', r'parsers'): (r'pure', r'parsers'),
 }
 
 def _checkmod(pkgname, modname, mod):
     expected = _cextversions.get((pkgname, modname))
     actual = getattr(mod, r'version', None)
     if actual != expected:
         raise ImportError(r'cannot import module %s.%s '
                           r'(expected version: %d, actual: %r)'
                           % (pkgname, modname, expected, actual))
 
 def importmod(modname):
     """Import module according to policy and check API version"""
     try:
         verpkg, purepkg = _packageprefs[policy]
     except KeyError:
         raise ImportError(r'invalid HGMODULEPOLICY %r' % policy)
     assert verpkg or purepkg
     if verpkg:
         pn, mn = _modredirects.get((verpkg, modname), (verpkg, modname))
         try:
             mod = _importfrom(pn, mn)
             if pn == verpkg:
                 _checkmod(pn, mn, mod)
             return mod
         except ImportError:
             if not purepkg:
                 raise
     pn, mn = _modredirects.get((purepkg, modname), (purepkg, modname))
     return _importfrom(pn, mn)
+
+def _isrustpermissive():
+    """Assuming the policy is a Rust one, tell if it's permissive."""
+    return policy.endswith(b'-allow')
+
+def importrust(modname, member=None, default=None):
+    """Import Rust module according to policy and availability.
+
+    If policy isn't a Rust one, this returns `default`.
+
+    If either the module or its member is not available, this returns `default`
+    if policy is permissive and raises `ImportError` if not.
+    """
+    if not policy.startswith(b'rust'):
+        return default
+
+    try:
+        mod = _importfrom(r'rustext', modname)
+    except ImportError:
+        if _isrustpermissive():
+            return default
+        raise
+    if member is None:
+        return mod
+
+    try:
+        return getattr(mod, member)
+    except AttributeError:
+        if _isrustpermissive():
+            return default
+        raise ImportError(r"Cannot import name %s" % member)

setup.py

@@ -1,1477 +1,1484 b''
 #
 # This is the mercurial setup script.
 #
 # 'python setup.py install', or
 # 'python setup.py --help' for more options
 
 import os
 
 supportedpy = '~= 2.7'
 if os.environ.get('HGALLOWPYTHON3', ''):
     # Mercurial will never work on Python 3 before 3.5 due to a lack
     # of % formatting on bytestrings, and can't work on 3.6.0 or 3.6.1
     # due to a bug in % formatting in bytestrings.
     # We cannot support Python 3.5.0, 3.5.1, 3.5.2 because of bug in
     # codecs.escape_encode() where it raises SystemError on empty bytestring
     # bug link: https://bugs.python.org/issue25270
     #
     # TODO: when we actually work on Python 3, use this string as the
     # actual supportedpy string.
     supportedpy = ','.join([
         '>=2.7',
         '!=3.0.*',
         '!=3.1.*',
         '!=3.2.*',
         '!=3.3.*',
         '!=3.4.*',
         '!=3.5.0',
         '!=3.5.1',
         '!=3.5.2',
         '!=3.6.0',
         '!=3.6.1',
     ])
 
 import sys, platform
 if sys.version_info[0] >= 3:
     printf = eval('print')
     libdir_escape = 'unicode_escape'
     def sysstr(s):
         return s.decode('latin-1')
 else:
     libdir_escape = 'string_escape'
     def printf(*args, **kwargs):
         f = kwargs.get('file', sys.stdout)
         end = kwargs.get('end', '\n')
         f.write(b' '.join(args) + end)
     def sysstr(s):
         return s
 
 # Attempt to guide users to a modern pip - this means that 2.6 users
 # should have a chance of getting a 4.2 release, and when we ratchet
 # the version requirement forward again hopefully everyone will get
 # something that works for them.
 if sys.version_info < (2, 7, 0, 'final'):
     pip_message = ('This may be due to an out of date pip. '
                    'Make sure you have pip >= 9.0.1.')
     try:
         import pip
         pip_version = tuple([int(x) for x in pip.__version__.split('.')[:3]])
         if pip_version < (9, 0, 1) :
             pip_message = (
                 'Your pip version is out of date, please install '
                 'pip >= 9.0.1. pip {} detected.'.format(pip.__version__))
         else:
             # pip is new enough - it must be something else
             pip_message = ''
     except Exception:
         pass
     error = """
 Mercurial does not support Python older than 2.7.
 Python {py} detected.
 {pip}
 """.format(py=sys.version_info, pip=pip_message)
     printf(error, file=sys.stderr)
     sys.exit(1)
 
 # We don't yet officially support Python 3. But we want to allow developers to
 # hack on. Detect and disallow running on Python 3 by default. But provide a
 # backdoor to enable working on Python 3.
 if sys.version_info[0] != 2:
     badpython = True
 
     # Allow Python 3 from source checkouts.
     if os.path.isdir('.hg') or 'HGPYTHON3' in os.environ:
         badpython = False
 
     if badpython:
         error = """
 Python {py} detected.
 
 Mercurial currently has beta support for Python 3 and use of Python 2.7 is
 recommended for the best experience.
 
 Please re-run with Python 2.7 for a faster, less buggy experience.
 
 If you would like to beta test Mercurial with Python 3, this error can
 be suppressed by defining the HGPYTHON3 environment variable when invoking
 this command. No special environment variables or configuration changes are
 necessary to run `hg` with Python 3.
 
 See https://www.mercurial-scm.org/wiki/Python3 for more on Mercurial's
 Python 3 support.
 """.format(py='.'.join('%d' % x for x in sys.version_info[0:2]))
 
         printf(error, file=sys.stderr)
         sys.exit(1)
 
 # Solaris Python packaging brain damage
 try:
     import hashlib
     sha = hashlib.sha1()
 except ImportError:
     try:
         import sha
         sha.sha # silence unused import warning
     except ImportError:
         raise SystemExit(
             "Couldn't import standard hashlib (incomplete Python install).")
 
 try:
     import zlib
     zlib.compressobj # silence unused import warning
 except ImportError:
     raise SystemExit(
         "Couldn't import standard zlib (incomplete Python install).")
 
 # The base IronPython distribution (as of 2.7.1) doesn't support bz2
 isironpython = False
 try:
     isironpython = (platform.python_implementation()
                     .lower().find("ironpython") != -1)
 except AttributeError:
     pass
 
 if isironpython:
     sys.stderr.write("warning: IronPython detected (no bz2 support)\n")
 else:
     try:
         import bz2
         bz2.BZ2Compressor # silence unused import warning
     except ImportError:
         raise SystemExit(
             "Couldn't import standard bz2 (incomplete Python install).")
 
 ispypy = "PyPy" in sys.version
 
 hgrustext = os.environ.get('HGWITHRUSTEXT')
 # TODO record it for proper rebuild upon changes
 # (see mercurial/__modulepolicy__.py)
 if hgrustext != 'cpython' and hgrustext is not None:
     hgrustext = 'direct-ffi'
 
 import ctypes
 import errno
 import stat, subprocess, time
 import re
 import shutil
 import tempfile
 from distutils import log
 # We have issues with setuptools on some platforms and builders. Until
 # those are resolved, setuptools is opt-in except for platforms where
 # we don't have issues.
 issetuptools = (os.name == 'nt' or 'FORCE_SETUPTOOLS' in os.environ)
 if issetuptools:
     from setuptools import setup
 else:
     from distutils.core import setup
 from distutils.ccompiler import new_compiler
 from distutils.core import Command, Extension
 from distutils.dist import Distribution
 from distutils.command.build import build
 from distutils.command.build_ext import build_ext
 from distutils.command.build_py import build_py
 from distutils.command.build_scripts import build_scripts
 from distutils.command.install import install
 from distutils.command.install_lib import install_lib
 from distutils.command.install_scripts import install_scripts
 from distutils.spawn import spawn, find_executable
 from distutils import file_util
 from distutils.errors import (
     CCompilerError,
     DistutilsError,
     DistutilsExecError,
 )
 from distutils.sysconfig import get_python_inc, get_config_var
 from distutils.version import StrictVersion
 
 # Explain to distutils.StrictVersion how our release candidates are versionned
 StrictVersion.version_re = re.compile(r'^(\d+)\.(\d+)(\.(\d+))?-?(rc(\d+))?$')
 
 def write_if_changed(path, content):
     """Write content to a file iff the content hasn't changed."""
     if os.path.exists(path):
         with open(path, 'rb') as fh:
             current = fh.read()
     else:
         current = b''
 
     if current != content:
         with open(path, 'wb') as fh:
             fh.write(content)
 
 scripts = ['hg']
 if os.name == 'nt':
     # We remove hg.bat if we are able to build hg.exe.
     scripts.append('contrib/win32/hg.bat')
 
 def cancompile(cc, code):
     tmpdir = tempfile.mkdtemp(prefix='hg-install-')
     devnull = oldstderr = None
     try:
         fname = os.path.join(tmpdir, 'testcomp.c')
         f = open(fname, 'w')
         f.write(code)
         f.close()
         # Redirect stderr to /dev/null to hide any error messages
         # from the compiler.
         # This will have to be changed if we ever have to check
         # for a function on Windows.
         devnull = open('/dev/null', 'w')
         oldstderr = os.dup(sys.stderr.fileno())
         os.dup2(devnull.fileno(), sys.stderr.fileno())
         objects = cc.compile([fname], output_dir=tmpdir)
         cc.link_executable(objects, os.path.join(tmpdir, "a.out"))
         return True
     except Exception:
         return False
     finally:
         if oldstderr is not None:
             os.dup2(oldstderr, sys.stderr.fileno())
         if devnull is not None:
             devnull.close()
         shutil.rmtree(tmpdir)
 
 # simplified version of distutils.ccompiler.CCompiler.has_function
 # that actually removes its temporary files.
 def hasfunction(cc, funcname):
     code = 'int main(void) { %s(); }\n' % funcname
     return cancompile(cc, code)
 
 def hasheader(cc, headername):
     code = '#include <%s>\nint main(void) { return 0; }\n' % headername
     return cancompile(cc, code)
 
 # py2exe needs to be installed to work
 try:
     import py2exe
     py2exe.Distribution # silence unused import warning
     py2exeloaded = True
     # import py2exe's patched Distribution class
     from distutils.core import Distribution
 except ImportError:
     py2exeloaded = False
 
 def runcmd(cmd, env, cwd=None):
     p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE, env=env, cwd=cwd)
     out, err = p.communicate()
     return p.returncode, out, err
 
 class hgcommand(object):
     def __init__(self, cmd, env):
         self.cmd = cmd
         self.env = env
 
     def run(self, args):
         cmd = self.cmd + args
         returncode, out, err = runcmd(cmd, self.env)
         err = filterhgerr(err)
         if err or returncode != 0:
             printf("stderr from '%s':" % (' '.join(cmd)), file=sys.stderr)
             printf(err, file=sys.stderr)
             return ''
         return out
 
 def filterhgerr(err):
     # If root is executing setup.py, but the repository is owned by
     # another user (as in "sudo python setup.py install") we will get
     # trust warnings since the .hg/hgrc file is untrusted. That is
     # fine, we don't want to load it anyway.  Python may warn about
     # a missing __init__.py in mercurial/locale, we also ignore that.
     err = [e for e in err.splitlines()
            if (not e.startswith(b'not trusting file')
                and not e.startswith(b'warning: Not importing')
                and not e.startswith(b'obsolete feature not enabled')
                and not e.startswith(b'*** failed to import extension')
                and not e.startswith(b'devel-warn:')
                and not (e.startswith(b'(third party extension')
                         and e.endswith(b'or newer of Mercurial; disabling)')))]
     return b'\n'.join(b'  ' + e for e in err)
 
 def findhg():
     """Try to figure out how we should invoke hg for examining the local
     repository contents.
 
     Returns an hgcommand object."""
     # By default, prefer the "hg" command in the user's path.  This was
     # presumably the hg command that the user used to create this repository.
     #
     # This repository may require extensions or other settings that would not
     # be enabled by running the hg script directly from this local repository.
     hgenv = os.environ.copy()
     # Use HGPLAIN to disable hgrc settings that would change output formatting,
     # and disable localization for the same reasons.
     hgenv['HGPLAIN'] = '1'
     hgenv['LANGUAGE'] = 'C'
     hgcmd = ['hg']
     # Run a simple "hg log" command just to see if using hg from the user's
     # path works and can successfully interact with this repository.  Windows
     # gives precedence to hg.exe in the current directory, so fall back to the
     # python invocation of local hg, where pythonXY.dll can always be found.
     check_cmd = ['log', '-r.', '-Ttest']
     if os.name != 'nt':
         try:
             retcode, out, err = runcmd(hgcmd + check_cmd, hgenv)
         except EnvironmentError:
             retcode = -1
         if retcode == 0 and not filterhgerr(err):
             return hgcommand(hgcmd, hgenv)
 
     # Fall back to trying the local hg installation.
     hgenv = localhgenv()
     hgcmd = [sys.executable, 'hg']
     try:
         retcode, out, err = runcmd(hgcmd + check_cmd, hgenv)
     except EnvironmentError:
         retcode = -1
     if retcode == 0 and not filterhgerr(err):
         return hgcommand(hgcmd, hgenv)
 
     raise SystemExit('Unable to find a working hg binary to extract the '
                      'version from the repository tags')
 
 def localhgenv():
     """Get an environment dictionary to use for invoking or importing
     mercurial from the local repository."""
     # Execute hg out of this directory with a custom environment which takes
     # care to not use any hgrc files and do no localization.
     env = {'HGMODULEPOLICY': 'py',
            'HGRCPATH': '',
            'LANGUAGE': 'C',
            'PATH': ''} # make pypi modules that use os.environ['PATH'] happy
     if 'LD_LIBRARY_PATH' in os.environ:
         env['LD_LIBRARY_PATH'] = os.environ['LD_LIBRARY_PATH']
     if 'SystemRoot' in os.environ:
         # SystemRoot is required by Windows to load various DLLs.  See:
         # https://bugs.python.org/issue13524#msg148850
         env['SystemRoot'] = os.environ['SystemRoot']
     return env
 
 version = ''
 
 if os.path.isdir('.hg'):
     hg = findhg()
     cmd = ['log', '-r', '.', '--template', '{tags}\n']
     numerictags = [t for t in sysstr(hg.run(cmd)).split() if t[0:1].isdigit()]
     hgid = sysstr(hg.run(['id', '-i'])).strip()
     if not hgid:
         # Bail out if hg is having problems interacting with this repository,
         # rather than falling through and producing a bogus version number.
         # Continuing with an invalid version number will break extensions
         # that define minimumhgversion.
         raise SystemExit('Unable to determine hg version from local repository')
     if numerictags: # tag(s) found
         version = numerictags[-1]
         if hgid.endswith('+'): # propagate the dirty status to the tag
             version += '+'
     else: # no tag found
         ltagcmd = ['parents', '--template', '{latesttag}']
         ltag = sysstr(hg.run(ltagcmd))
         changessincecmd = ['log', '-T', 'x\n', '-r', "only(.,'%s')" % ltag]
         changessince = len(hg.run(changessincecmd).splitlines())
         version = '%s+%s-%s' % (ltag, changessince, hgid)
     if version.endswith('+'):
         version += time.strftime('%Y%m%d')
 elif os.path.exists('.hg_archival.txt'):
     kw = dict([[t.strip() for t in l.split(':', 1)]
                for l in open('.hg_archival.txt')])
     if 'tag' in kw:
         version = kw['tag']
     elif 'latesttag' in kw:
         if 'changessincelatesttag' in kw:
             version = '%(latesttag)s+%(changessincelatesttag)s-%(node).12s' % kw
         else:
             version = '%(latesttag)s+%(latesttagdistance)s-%(node).12s' % kw
     else:
         version = kw.get('node', '')[:12]
 
 if version:
     versionb = version
     if not isinstance(versionb, bytes):
         versionb = versionb.encode('ascii')
 
     write_if_changed('mercurial/__version__.py', b''.join([
         b'# this file is autogenerated by setup.py\n'
         b'version = b"%s"\n' % versionb,
     ]))
 
 try:
     oldpolicy = os.environ.get('HGMODULEPOLICY', None)
     os.environ['HGMODULEPOLICY'] = 'py'
     from mercurial import __version__
     version = __version__.version
 except ImportError:
     version = b'unknown'
 finally:
     if oldpolicy is None:
         del os.environ['HGMODULEPOLICY']
     else:
         os.environ['HGMODULEPOLICY'] = oldpolicy
 
 class hgbuild(build):
     # Insert hgbuildmo first so that files in mercurial/locale/ are found
     # when build_py is run next.
     sub_commands = [('build_mo', None)] + build.sub_commands
 
 class hgbuildmo(build):
 
     description = "build translations (.mo files)"
 
     def run(self):
         if not find_executable('msgfmt'):
             self.warn("could not find msgfmt executable, no translations "
                      "will be built")
             return
 
         podir = 'i18n'
         if not os.path.isdir(podir):
             self.warn("could not find %s/ directory" % podir)
             return
 
         join = os.path.join
         for po in os.listdir(podir):
             if not po.endswith('.po'):
                 continue
             pofile = join(podir, po)
             modir = join('locale', po[:-3], 'LC_MESSAGES')
             mofile = join(modir, 'hg.mo')
             mobuildfile = join('mercurial', mofile)
             cmd = ['msgfmt', '-v', '-o', mobuildfile, pofile]
             if sys.platform != 'sunos5':
                 # msgfmt on Solaris does not know about -c
                 cmd.append('-c')
             self.mkpath(join('mercurial', modir))
             self.make_file([pofile], mobuildfile, spawn, (cmd,))
 
 
 class hgdist(Distribution):
     pure = False
     cffi = ispypy
 
     global_options = Distribution.global_options + [
         ('pure', None, "use pure (slow) Python code instead of C extensions"),
     ]
 
     def has_ext_modules(self):
         # self.ext_modules is emptied in hgbuildpy.finalize_options which is
         # too late for some cases
         return not self.pure and Distribution.has_ext_modules(self)
 
 # This is ugly as a one-liner. So use a variable.
 buildextnegops = dict(getattr(build_ext, 'negative_options', {}))
 buildextnegops['no-zstd'] = 'zstd'
 
 class hgbuildext(build_ext):
     user_options = build_ext.user_options + [
         ('zstd', None, 'compile zstd bindings [default]'),
         ('no-zstd', None, 'do not compile zstd bindings'),
     ]
 
     boolean_options = build_ext.boolean_options + ['zstd']
     negative_opt = buildextnegops
 
     def initialize_options(self):
         self.zstd = True
         return build_ext.initialize_options(self)
 
     def build_extensions(self):
         ruststandalones = [e for e in self.extensions
                            if isinstance(e, RustStandaloneExtension)]
         self.extensions = [e for e in self.extensions
                            if e not in ruststandalones]
         # Filter out zstd if disabled via argument.
         if not self.zstd:
             self.extensions = [e for e in self.extensions
                                if e.name != 'mercurial.zstd']
 
         for rustext in ruststandalones:
             rustext.build('' if self.inplace else self.build_lib)
 
         return build_ext.build_extensions(self)
 
     def build_extension(self, ext):
         if isinstance(ext, RustExtension):
             ext.rustbuild()
         try:
             build_ext.build_extension(self, ext)
         except CCompilerError:
             if not getattr(ext, 'optional', False):
                 raise
             log.warn("Failed to build optional extension '%s' (skipping)",
                      ext.name)
 
 class hgbuildscripts(build_scripts):
     def run(self):
         if os.name != 'nt' or self.distribution.pure:
             return build_scripts.run(self)
 
         exebuilt = False
         try:
             self.run_command('build_hgexe')
             exebuilt = True
         except (DistutilsError, CCompilerError):
             log.warn('failed to build optional hg.exe')
 
         if exebuilt:
             # Copying hg.exe to the scripts build directory ensures it is
             # installed by the install_scripts command.
             hgexecommand = self.get_finalized_command('build_hgexe')
             dest = os.path.join(self.build_dir, 'hg.exe')
             self.mkpath(self.build_dir)
             self.copy_file(hgexecommand.hgexepath, dest)
 
             # Remove hg.bat because it is redundant with hg.exe.
             self.scripts.remove('contrib/win32/hg.bat')
 
         return build_scripts.run(self)
 
 class hgbuildpy(build_py):
     def finalize_options(self):
         build_py.finalize_options(self)
 
         if self.distribution.pure:
             self.distribution.ext_modules = []
         elif self.distribution.cffi:
             from mercurial.cffi import (
                 bdiffbuild,
                 mpatchbuild,
             )
             exts = [mpatchbuild.ffi.distutils_extension(),
                     bdiffbuild.ffi.distutils_extension()]
             # cffi modules go here
             if sys.platform == 'darwin':
                 from mercurial.cffi import osutilbuild
                 exts.append(osutilbuild.ffi.distutils_extension())
             self.distribution.ext_modules = exts
         else:
             h = os.path.join(get_python_inc(), 'Python.h')
             if not os.path.exists(h):
                 raise SystemExit('Python headers are required to build '
                                  'Mercurial but weren\'t found in %s' % h)
 
     def run(self):
         basepath = os.path.join(self.build_lib, 'mercurial')
         self.mkpath(basepath)
 
         if self.distribution.pure:
             modulepolicy = 'py'
         elif self.build_lib == '.':
-            # in-place build should run without rebuilding C extensions
-            modulepolicy = 'allow'
+            # in-place build should run without rebuilding C
+            # and Rust extensions
+            if hgrustext == 'cpython':
+                modulepolicy = 'rust+c-allow'
+            else:
+                modulepolicy = 'allow'
         else:
-            modulepolicy = 'c'
+            if hgrustext == 'cpython':
+                modulepolicy = 'rust+c'
+            else:
+                modulepolicy = 'c'
 
         content = b''.join([
             b'# this file is autogenerated by setup.py\n',
             b'modulepolicy = b"%s"\n' % modulepolicy.encode('ascii'),
         ])
         write_if_changed(os.path.join(basepath, '__modulepolicy__.py'),
                          content)
 
         build_py.run(self)
 
 class buildhgextindex(Command):
     description = 'generate prebuilt index of hgext (for frozen package)'
     user_options = []
     _indexfilename = 'hgext/__index__.py'
 
     def initialize_options(self):
         pass
 
     def finalize_options(self):
         pass
 
     def run(self):
         if os.path.exists(self._indexfilename):
             with open(self._indexfilename, 'w') as f:
                 f.write('# empty\n')
 
         # here no extension enabled, disabled() lists up everything
         code = ('import pprint; from mercurial import extensions; '
                 'pprint.pprint(extensions.disabled())')
         returncode, out, err = runcmd([sys.executable, '-c', code],
                                       localhgenv())
         if err or returncode != 0:
             raise DistutilsExecError(err)
 
         with open(self._indexfilename, 'wb') as f:
             f.write(b'# this file is autogenerated by setup.py\n')
             f.write(b'docs = ')
             f.write(out)
 
 class buildhgexe(build_ext):
     description = 'compile hg.exe from mercurial/exewrapper.c'
     user_options = build_ext.user_options + [
         ('long-paths-support', None, 'enable support for long paths on '
                                      'Windows (off by default and '
                                      'experimental)'),
     ]
 
     LONG_PATHS_MANIFEST = """
     <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
     <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
         <application>
             <windowsSettings
             xmlns:ws2="http://schemas.microsoft.com/SMI/2016/WindowsSettings">
                 <ws2:longPathAware>true</ws2:longPathAware>
             </windowsSettings>
         </application>
     </assembly>"""
 
     def initialize_options(self):
         build_ext.initialize_options(self)
         self.long_paths_support = False
 
     def build_extensions(self):
         if os.name != 'nt':
             return
         if isinstance(self.compiler, HackedMingw32CCompiler):
             self.compiler.compiler_so = self.compiler.compiler # no -mdll
             self.compiler.dll_libraries = [] # no -lmsrvc90
 
         # Different Python installs can have different Python library
         # names. e.g. the official CPython distribution uses pythonXY.dll
         # and MinGW uses libpythonX.Y.dll.
         _kernel32 = ctypes.windll.kernel32
         _kernel32.GetModuleFileNameA.argtypes = [ctypes.c_void_p,
                                                  ctypes.c_void_p,
                                                  ctypes.c_ulong]
         _kernel32.GetModuleFileNameA.restype = ctypes.c_ulong
         size = 1000
         buf = ctypes.create_string_buffer(size + 1)
         filelen = _kernel32.GetModuleFileNameA(sys.dllhandle, ctypes.byref(buf),
                                                size)
 
         if filelen > 0 and filelen != size:
             dllbasename = os.path.basename(buf.value)
             if not dllbasename.lower().endswith(b'.dll'):
                 raise SystemExit('Python DLL does not end with .dll: %s' %
                                  dllbasename)
             pythonlib = dllbasename[:-4]
         else:
             log.warn('could not determine Python DLL filename; '
                      'assuming pythonXY')
 
             hv = sys.hexversion
             pythonlib = 'python%d%d' % (hv >> 24, (hv >> 16) & 0xff)
 
         log.info('using %s as Python library name' % pythonlib)
         with open('mercurial/hgpythonlib.h', 'wb') as f:
             f.write(b'/* this file is autogenerated by setup.py */\n')
             f.write(b'#define HGPYTHONLIB "%s"\n' % pythonlib)
 
         macros = None
         if sys.version_info[0] >= 3:
             macros = [('_UNICODE', None), ('UNICODE', None)]
 
         objects = self.compiler.compile(['mercurial/exewrapper.c'],
                                          output_dir=self.build_temp,
                                          macros=macros)
         dir = os.path.dirname(self.get_ext_fullpath('dummy'))
         self.hgtarget = os.path.join(dir, 'hg')
         self.compiler.link_executable(objects, self.hgtarget,
                                       libraries=[],
                                       output_dir=self.build_temp)
         if self.long_paths_support:
             self.addlongpathsmanifest()
 
     def addlongpathsmanifest(self):
         r"""Add manifest pieces so that hg.exe understands long paths
 
         This is an EXPERIMENTAL feature, use with care.
         To enable long paths support, one needs to do two things:
         - build Mercurial with --long-paths-support option
         - change HKLM\SYSTEM\CurrentControlSet\Control\FileSystem\
                  LongPathsEnabled to have value 1.
 
         Please ignore 'warning 81010002: Unrecognized Element "longPathAware"';
         it happens because Mercurial uses mt.exe circa 2008, which is not
         yet aware of long paths support in the manifest (I think so at least).
         This does not stop mt.exe from embedding/merging the XML properly.
 
         Why resource #1 should be used for .exe manifests? I don't know and
         wasn't able to find an explanation for mortals. But it seems to work.
         """
         exefname = self.compiler.executable_filename(self.hgtarget)
         fdauto, manfname = tempfile.mkstemp(suffix='.hg.exe.manifest')
         os.close(fdauto)
         with open(manfname, 'w') as f:
             f.write(self.LONG_PATHS_MANIFEST)
         log.info("long paths manifest is written to '%s'" % manfname)
         inputresource = '-inputresource:%s;#1' % exefname
         outputresource = '-outputresource:%s;#1' % exefname
         log.info("running mt.exe to update hg.exe's manifest in-place")
         # supplying both -manifest and -inputresource to mt.exe makes
         # it merge the embedded and supplied manifests in the -outputresource
         self.spawn(['mt.exe', '-nologo', '-manifest', manfname,
                     inputresource, outputresource])
         log.info("done updating hg.exe's manifest")
         os.remove(manfname)
 
     @property
     def hgexepath(self):
         dir = os.path.dirname(self.get_ext_fullpath('dummy'))
         return os.path.join(self.build_temp, dir, 'hg.exe')
 
 class hgbuilddoc(Command):
     description = 'build documentation'
     user_options = [
         ('man', None, 'generate man pages'),
         ('html', None, 'generate html pages'),
     ]
 
     def initialize_options(self):
         self.man = None
         self.html = None
 
     def finalize_options(self):
         # If --man or --html are set, only generate what we're told to.
         # Otherwise generate everything.
         have_subset = self.man is not None or self.html is not None
 
         if have_subset:
             self.man = True if self.man else False
             self.html = True if self.html else False
         else:
             self.man = True
             self.html = True
 
     def run(self):
         def normalizecrlf(p):
             with open(p, 'rb') as fh:
                 orig = fh.read()
 
             if b'\r\n' not in orig:
                 return
 
             log.info('normalizing %s to LF line endings' % p)
             with open(p, 'wb') as fh:
                 fh.write(orig.replace(b'\r\n', b'\n'))
 
         def gentxt(root):
             txt = 'doc/%s.txt' % root
             log.info('generating %s' % txt)
             res, out, err = runcmd(
                 [sys.executable, 'gendoc.py', root],
                 os.environ,
                 cwd='doc')
             if res:
                 raise SystemExit('error running gendoc.py: %s' %
                                  '\n'.join([out, err]))
 
             with open(txt, 'wb') as fh:
                 fh.write(out)
 
         def gengendoc(root):
             gendoc = 'doc/%s.gendoc.txt' % root
 
             log.info('generating %s' % gendoc)
             res, out, err = runcmd(
                 [sys.executable, 'gendoc.py', '%s.gendoc' % root],
                 os.environ,
                 cwd='doc')
             if res:
                 raise SystemExit('error running gendoc: %s' %
                                  '\n'.join([out, err]))
 
             with open(gendoc, 'wb') as fh:
                 fh.write(out)
 
         def genman(root):
             log.info('generating doc/%s' % root)
             res, out, err = runcmd(
                 [sys.executable, 'runrst', 'hgmanpage', '--halt', 'warning',
                  '--strip-elements-with-class', 'htmlonly',
                  '%s.txt' % root, root],
                 os.environ,
                 cwd='doc')
             if res:
                 raise SystemExit('error running runrst: %s' %
                                  '\n'.join([out, err]))
 
             normalizecrlf('doc/%s' % root)
 
         def genhtml(root):
             log.info('generating doc/%s.html' % root)
             res, out, err = runcmd(
                 [sys.executable, 'runrst', 'html', '--halt', 'warning',
                  '--link-stylesheet', '--stylesheet-path', 'style.css',
                  '%s.txt' % root, '%s.html' % root],
                 os.environ,
                 cwd='doc')
             if res:
                 raise SystemExit('error running runrst: %s' %
                                  '\n'.join([out, err]))
 
             normalizecrlf('doc/%s.html' % root)
 
         # This logic is duplicated in doc/Makefile.
         sources = set(f for f in os.listdir('mercurial/help')
                       if re.search(r'[0-9]\.txt$', f))
 
         # common.txt is a one-off.
         gentxt('common')
 
         for source in sorted(sources):
             assert source[-4:] == '.txt'
             root = source[:-4]
 
             gentxt(root)
             gengendoc(root)
 
             if self.man:
                 genman(root)
             if self.html:
                 genhtml(root)
 
 class hginstall(install):
 
     user_options = install.user_options + [
         ('old-and-unmanageable', None,
          'noop, present for eggless setuptools compat'),
         ('single-version-externally-managed', None,
          'noop, present for eggless setuptools compat'),
     ]
 
     # Also helps setuptools not be sad while we refuse to create eggs.
     single_version_externally_managed = True
 
     def get_sub_commands(self):
         # Screen out egg related commands to prevent egg generation.  But allow
         # mercurial.egg-info generation, since that is part of modern
         # packaging.
         excl = set(['bdist_egg'])
         return filter(lambda x: x not in excl, install.get_sub_commands(self))
 
 class hginstalllib(install_lib):
     '''
     This is a specialization of install_lib that replaces the copy_file used
     there so that it supports setting the mode of files after copying them,
     instead of just preserving the mode that the files originally had.  If your
     system has a umask of something like 027, preserving the permissions when
     copying will lead to a broken install.
 
     Note that just passing keep_permissions=False to copy_file would be
     insufficient, as it might still be applying a umask.
     '''
 
     def run(self):
         realcopyfile = file_util.copy_file
         def copyfileandsetmode(*args, **kwargs):
             src, dst = args[0], args[1]
             dst, copied = realcopyfile(*args, **kwargs)
             if copied:
                 st = os.stat(src)
                 # Persist executable bit (apply it to group and other if user
                 # has it)
                 if st[stat.ST_MODE] & stat.S_IXUSR:
                     setmode = int('0755', 8)
                 else:
                     setmode = int('0644', 8)
                 m = stat.S_IMODE(st[stat.ST_MODE])
                 m = (m & ~int('0777', 8)) | setmode
                 os.chmod(dst, m)
         file_util.copy_file = copyfileandsetmode
         try:
             install_lib.run(self)
         finally:
             file_util.copy_file = realcopyfile
 
 class hginstallscripts(install_scripts):
     '''
     This is a specialization of install_scripts that replaces the @LIBDIR@ with
     the configured directory for modules. If possible, the path is made relative
     to the directory for scripts.
     '''
 
     def initialize_options(self):
         install_scripts.initialize_options(self)
 
         self.install_lib = None
 
     def finalize_options(self):
         install_scripts.finalize_options(self)
         self.set_undefined_options('install',
                                    ('install_lib', 'install_lib'))
 
     def run(self):
         install_scripts.run(self)
 
         # It only makes sense to replace @LIBDIR@ with the install path if
         # the install path is known. For wheels, the logic below calculates
         # the libdir to be "../..". This is because the internal layout of a
         # wheel archive looks like:
         #
         #   mercurial-3.6.1.data/scripts/hg
         #   mercurial/__init__.py
         #
         # When installing wheels, the subdirectories of the "<pkg>.data"
         # directory are translated to system local paths and files therein
         # are copied in place. The mercurial/* files are installed into the
         # site-packages directory. However, the site-packages directory
         # isn't known until wheel install time. This means we have no clue
         # at wheel generation time what the installed site-packages directory
         # will be. And, wheels don't appear to provide the ability to register
         # custom code to run during wheel installation. This all means that
         # we can't reliably set the libdir in wheels: the default behavior
         # of looking in sys.path must do.
 
         if (os.path.splitdrive(self.install_dir)[0] !=
             os.path.splitdrive(self.install_lib)[0]):
             # can't make relative paths from one drive to another, so use an
             # absolute path instead
             libdir = self.install_lib
         else:
             common = os.path.commonprefix((self.install_dir, self.install_lib))
             rest = self.install_dir[len(common):]
             uplevel = len([n for n in os.path.split(rest) if n])
 
             libdir = uplevel * ('..' + os.sep) + self.install_lib[len(common):]
 
         for outfile in self.outfiles:
             with open(outfile, 'rb') as fp:
                 data = fp.read()
 
             # skip binary files
             if b'\0' in data:
                 continue
 
             # During local installs, the shebang will be rewritten to the final
             # install path. During wheel packaging, the shebang has a special
             # value.
             if data.startswith(b'#!python'):
                 log.info('not rewriting @LIBDIR@ in %s because install path '
                          'not known' % outfile)
                 continue
 
             data = data.replace(b'@LIBDIR@', libdir.encode(libdir_escape))
             with open(outfile, 'wb') as fp:
                 fp.write(data)
 
 # virtualenv installs custom distutils/__init__.py and
 # distutils/distutils.cfg files which essentially proxy back to the
 # "real" distutils in the main Python install. The presence of this
 # directory causes py2exe to pick up the "hacked" distutils package
 # from the virtualenv and "import distutils" will fail from the py2exe
 # build because the "real" distutils files can't be located.
 #
 # We work around this by monkeypatching the py2exe code finding Python
 # modules to replace the found virtualenv distutils modules with the
 # original versions via filesystem scanning. This is a bit hacky. But
 # it allows us to use virtualenvs for py2exe packaging, which is more
 # deterministic and reproducible.
 #
 # It's worth noting that the common StackOverflow suggestions for this
 # problem involve copying the original distutils files into the
 # virtualenv or into the staging directory after setup() is invoked.
 # The former is very brittle and can easily break setup(). Our hacking
 # of the found modules routine has a similar result as copying the files
 # manually. But it makes fewer assumptions about how py2exe works and
 # is less brittle.
 
 # This only catches virtualenvs made with virtualenv (as opposed to
 # venv, which is likely what Python 3 uses).
 py2exehacked = py2exeloaded and getattr(sys, 'real_prefix', None) is not None
 
 if py2exehacked:
     from distutils.command.py2exe import py2exe as buildpy2exe
     from py2exe.mf import Module as py2exemodule
 
     class hgbuildpy2exe(buildpy2exe):
         def find_needed_modules(self, mf, files, modules):
             res = buildpy2exe.find_needed_modules(self, mf, files, modules)
 
             # Replace virtualenv's distutils modules with the real ones.
             modules = {}
             for k, v in res.modules.items():
                 if k != 'distutils' and not k.startswith('distutils.'):
                     modules[k] = v
 
             res.modules = modules
 
             import opcode
             distutilsreal = os.path.join(os.path.dirname(opcode.__file__),
                                          'distutils')
 
             for root, dirs, files in os.walk(distutilsreal):
                 for f in sorted(files):
                     if not f.endswith('.py'):
                         continue
 
                     full = os.path.join(root, f)
 
                     parents = ['distutils']
 
                     if root != distutilsreal:
                         rel = os.path.relpath(root, distutilsreal)
                         parents.extend(p for p in rel.split(os.sep))
 
                     modname = '%s.%s' % ('.'.join(parents), f[:-3])
 
                     if modname.startswith('distutils.tests.'):
                         continue
 
                     if modname.endswith('.__init__'):
                         modname = modname[:-len('.__init__')]
                         path = os.path.dirname(full)
                     else:
                         path = None
 
                     res.modules[modname] = py2exemodule(modname, full,
                                                         path=path)
 
             if 'distutils' not in res.modules:
                 raise SystemExit('could not find distutils modules')
 
             return res
 
 cmdclass = {'build': hgbuild,
             'build_doc': hgbuilddoc,
             'build_mo': hgbuildmo,
             'build_ext': hgbuildext,
             'build_py': hgbuildpy,
             'build_scripts': hgbuildscripts,
             'build_hgextindex': buildhgextindex,
             'install': hginstall,
             'install_lib': hginstalllib,
             'install_scripts': hginstallscripts,
             'build_hgexe': buildhgexe,
             }
 
 if py2exehacked:
     cmdclass['py2exe'] = hgbuildpy2exe
 
 packages = ['mercurial',
             'mercurial.cext',
             'mercurial.cffi',
             'mercurial.hgweb',
             'mercurial.pure',
             'mercurial.thirdparty',
             'mercurial.thirdparty.attr',
             'mercurial.thirdparty.zope',
             'mercurial.thirdparty.zope.interface',
             'mercurial.utils',
             'mercurial.revlogutils',
             'mercurial.testing',
             'hgext', 'hgext.convert', 'hgext.fsmonitor',
             'hgext.fastannotate',
             'hgext.fsmonitor.pywatchman',
             'hgext.infinitepush',
             'hgext.highlight',
             'hgext.largefiles', 'hgext.lfs', 'hgext.narrow',
             'hgext.remotefilelog',
             'hgext.zeroconf', 'hgext3rd',
             'hgdemandimport']
 if sys.version_info[0] == 2:
     packages.extend(['mercurial.thirdparty.concurrent',
                      'mercurial.thirdparty.concurrent.futures'])
 
 if 'HG_PY2EXE_EXTRA_INSTALL_PACKAGES' in os.environ:
     # py2exe can't cope with namespace packages very well, so we have to
     # install any hgext3rd.* extensions that we want in the final py2exe
     # image here. This is gross, but you gotta do what you gotta do.
     packages.extend(os.environ['HG_PY2EXE_EXTRA_INSTALL_PACKAGES'].split(' '))
 
 common_depends = ['mercurial/bitmanipulation.h',
                   'mercurial/compat.h',
                   'mercurial/cext/util.h']
 common_include_dirs = ['mercurial']
 
 osutil_cflags = []
 osutil_ldflags = []
 
 # platform specific macros
 for plat, func in [('bsd', 'setproctitle')]:
     if re.search(plat, sys.platform) and hasfunction(new_compiler(), func):
         osutil_cflags.append('-DHAVE_%s' % func.upper())
 
 for plat, macro, code in [
     ('bsd|darwin', 'BSD_STATFS', '''
      #include <sys/param.h>
      #include <sys/mount.h>
      int main() { struct statfs s; return sizeof(s.f_fstypename); }
      '''),
     ('linux', 'LINUX_STATFS', '''
      #include <linux/magic.h>
      #include <sys/vfs.h>
      int main() { struct statfs s; return sizeof(s.f_type); }
      '''),
 ]:
     if re.search(plat, sys.platform) and cancompile(new_compiler(), code):
         osutil_cflags.append('-DHAVE_%s' % macro)
 
 if sys.platform == 'darwin':
     osutil_ldflags += ['-framework', 'ApplicationServices']
 
 xdiff_srcs = [
     'mercurial/thirdparty/xdiff/xdiffi.c',
     'mercurial/thirdparty/xdiff/xprepare.c',
     'mercurial/thirdparty/xdiff/xutils.c',
 ]
 
 xdiff_headers = [
     'mercurial/thirdparty/xdiff/xdiff.h',
     'mercurial/thirdparty/xdiff/xdiffi.h',
     'mercurial/thirdparty/xdiff/xinclude.h',
     'mercurial/thirdparty/xdiff/xmacros.h',
     'mercurial/thirdparty/xdiff/xprepare.h',
     'mercurial/thirdparty/xdiff/xtypes.h',
     'mercurial/thirdparty/xdiff/xutils.h',
 ]
 
 class RustCompilationError(CCompilerError):
     """Exception class for Rust compilation errors."""
 
 class RustExtension(Extension):
     """Base classes for concrete Rust Extension classes.
     """
 
     rusttargetdir = os.path.join('rust', 'target', 'release')
 
     def __init__(self, mpath, sources, rustlibname, subcrate,
                  py3_features=None, **kw):
         Extension.__init__(self, mpath, sources, **kw)
         if hgrustext is None:
             return
         srcdir = self.rustsrcdir = os.path.join('rust', subcrate)
         self.py3_features = py3_features
 
         # adding Rust source and control files to depends so that the extension
         # gets rebuilt if they've changed
         self.depends.append(os.path.join(srcdir, 'Cargo.toml'))
         cargo_lock = os.path.join(srcdir, 'Cargo.lock')
         if os.path.exists(cargo_lock):
             self.depends.append(cargo_lock)
         for dirpath, subdir, fnames in os.walk(os.path.join(srcdir, 'src')):
             self.depends.extend(os.path.join(dirpath, fname)
                                 for fname in fnames
                                 if os.path.splitext(fname)[1] == '.rs')
 
     def rustbuild(self):
         if hgrustext is None:
             return
         env = os.environ.copy()
         if 'HGTEST_RESTOREENV' in env:
             # Mercurial tests change HOME to a temporary directory,
             # but, if installed with rustup, the Rust toolchain needs
             # HOME to be correct (otherwise the 'no default toolchain'
             # error message is issued and the build fails).
             # This happens currently with test-hghave.t, which does
             # invoke this build.
 
             # Unix only fix (os.path.expanduser not really reliable if
             # HOME is shadowed like this)
             import pwd
             env['HOME'] = pwd.getpwuid(os.getuid()).pw_dir
 
         cargocmd = ['cargo', 'build', '-vv', '--release']
         if sys.version_info[0] == 3 and self.py3_features is not None:
             cargocmd.extend(('--features', self.py3_features,
                              '--no-default-features'))
         try:
             subprocess.check_call(cargocmd, env=env, cwd=self.rustsrcdir)
         except OSError as exc:
             if exc.errno == errno.ENOENT:
                 raise RustCompilationError("Cargo not found")
             elif exc.errno == errno.EACCES:
                 raise RustCompilationError(
                     "Cargo found, but permisssion to execute it is denied")
             else:
                 raise
         except subprocess.CalledProcessError:
             raise RustCompilationError(
                 "Cargo failed. Working directory: %r, "
                 "command: %r, environment: %r"
                 % (self.rustsrcdir, cargocmd, env))
 
 class RustEnhancedExtension(RustExtension):
     """A C Extension, conditionally enhanced with Rust code.
 
     If the HGRUSTEXT environment variable is set to something else
     than 'cpython', the Rust sources get compiled and linked within the
     C target shared library object.
     """
 
     def __init__(self, mpath, sources, rustlibname, subcrate, **kw):
         RustExtension.__init__(self, mpath, sources, rustlibname, subcrate,
                                **kw)
         if hgrustext != 'direct-ffi':
             return
         self.extra_compile_args.append('-DWITH_RUST')
         self.libraries.append(rustlibname)
         self.library_dirs.append(self.rusttargetdir)
 
 class RustStandaloneExtension(RustExtension):
 
     def __init__(self, pydottedname, rustcrate, dylibname, **kw):
         RustExtension.__init__(self, pydottedname, [], dylibname, rustcrate,
                                **kw)
         self.dylibname = dylibname
 
     def build(self, target_dir):
         self.rustbuild()
         target = [target_dir]
         target.extend(self.name.split('.'))
         ext = '.so'  # TODO Unix only
         target[-1] += ext
         shutil.copy2(os.path.join(self.rusttargetdir, self.dylibname + ext),
                      os.path.join(*target))
 
 
 extmodules = [
     Extension('mercurial.cext.base85', ['mercurial/cext/base85.c'],
               include_dirs=common_include_dirs,
               depends=common_depends),
     Extension('mercurial.cext.bdiff', ['mercurial/bdiff.c',
                                        'mercurial/cext/bdiff.c'] + xdiff_srcs,
               include_dirs=common_include_dirs,
               depends=common_depends + ['mercurial/bdiff.h'] + xdiff_headers),
     Extension('mercurial.cext.mpatch', ['mercurial/mpatch.c',
                                         'mercurial/cext/mpatch.c'],
               include_dirs=common_include_dirs,
               depends=common_depends),
     RustEnhancedExtension(
         'mercurial.cext.parsers', ['mercurial/cext/charencode.c',
                                    'mercurial/cext/dirs.c',
                                    'mercurial/cext/manifest.c',
                                    'mercurial/cext/parsers.c',
                                    'mercurial/cext/pathencode.c',
                                    'mercurial/cext/revlog.c'],
         'hgdirectffi',
         'hg-direct-ffi',
         include_dirs=common_include_dirs,
         depends=common_depends + ['mercurial/cext/charencode.h',
                                   'mercurial/cext/revlog.h',
                                   'rust/hg-core/src/ancestors.rs',
                                   'rust/hg-core/src/lib.rs']),
     Extension('mercurial.cext.osutil', ['mercurial/cext/osutil.c'],
               include_dirs=common_include_dirs,
               extra_compile_args=osutil_cflags,
               extra_link_args=osutil_ldflags,
               depends=common_depends),
     Extension(
         'mercurial.thirdparty.zope.interface._zope_interface_coptimizations', [
         'mercurial/thirdparty/zope/interface/_zope_interface_coptimizations.c',
         ]),
     Extension('hgext.fsmonitor.pywatchman.bser',
               ['hgext/fsmonitor/pywatchman/bser.c']),
     ]
 
 if hgrustext == 'cpython':
     extmodules.append(
         RustStandaloneExtension('mercurial.rustext', 'hg-cpython', 'librusthg',
                                 py3_features='python3')
     )
 
 
 sys.path.insert(0, 'contrib/python-zstandard')
 import setup_zstd
 extmodules.append(setup_zstd.get_c_extension(
     name='mercurial.zstd',
     root=os.path.abspath(os.path.dirname(__file__))))
 
 try:
     from distutils import cygwinccompiler
 
     # the -mno-cygwin option has been deprecated for years
     mingw32compilerclass = cygwinccompiler.Mingw32CCompiler
 
     class HackedMingw32CCompiler(cygwinccompiler.Mingw32CCompiler):
         def __init__(self, *args, **kwargs):
             mingw32compilerclass.__init__(self, *args, **kwargs)
             for i in 'compiler compiler_so linker_exe linker_so'.split():
                 try:
                     getattr(self, i).remove('-mno-cygwin')
                 except ValueError:
                     pass
 
     cygwinccompiler.Mingw32CCompiler = HackedMingw32CCompiler
 except ImportError:
     # the cygwinccompiler package is not available on some Python
     # distributions like the ones from the optware project for Synology
     # DiskStation boxes
     class HackedMingw32CCompiler(object):
         pass
 
 if os.name == 'nt':
     # Allow compiler/linker flags to be added to Visual Studio builds.  Passing
     # extra_link_args to distutils.extensions.Extension() doesn't have any
     # effect.
     from distutils import msvccompiler
 
     msvccompilerclass = msvccompiler.MSVCCompiler
 
     class HackedMSVCCompiler(msvccompiler.MSVCCompiler):
         def initialize(self):
             msvccompilerclass.initialize(self)
             # "warning LNK4197: export 'func' specified multiple times"
             self.ldflags_shared.append('/ignore:4197')
             self.ldflags_shared_debug.append('/ignore:4197')
 
     msvccompiler.MSVCCompiler = HackedMSVCCompiler
 
 packagedata = {'mercurial': ['locale/*/LC_MESSAGES/hg.mo',
                              'help/*.txt',
                              'help/internals/*.txt',
                              'default.d/*.rc',
                              'dummycert.pem']}
 
 def ordinarypath(p):
     return p and p[0] != '.' and p[-1] != '~'
 
 for root in ('templates',):
     for curdir, dirs, files in os.walk(os.path.join('mercurial', root)):
         curdir = curdir.split(os.sep, 1)[1]
         dirs[:] = filter(ordinarypath, dirs)
         for f in filter(ordinarypath, files):
             f = os.path.join(curdir, f)
             packagedata['mercurial'].append(f)
 
 datafiles = []
 
 # distutils expects version to be str/unicode. Converting it to
 # unicode on Python 2 still works because it won't contain any
 # non-ascii bytes and will be implicitly converted back to bytes
 # when operated on.
 assert isinstance(version, bytes)
 setupversion = version.decode('ascii')
 
 extra = {}
 
 py2exepackages = [
     'hgdemandimport',
     'hgext3rd',
     'hgext',
     'email',
     # implicitly imported per module policy
     # (cffi wouldn't be used as a frozen exe)
     'mercurial.cext',
     #'mercurial.cffi',
     'mercurial.pure',
 ]
 
 py2exeexcludes = []
 py2exedllexcludes = ['crypt32.dll']
 
 if issetuptools:
     extra['python_requires'] = supportedpy
 
 if py2exeloaded:
     extra['console'] = [
         {'script':'hg',
          'copyright':'Copyright (C) 2005-2019 Matt Mackall and others',
          'product_version':version}]
     # Sub command of 'build' because 'py2exe' does not handle sub_commands.
     # Need to override hgbuild because it has a private copy of
     # build.sub_commands.
     hgbuild.sub_commands.insert(0, ('build_hgextindex', None))
     # put dlls in sub directory so that they won't pollute PATH
     extra['zipfile'] = 'lib/library.zip'
 
     # We allow some configuration to be supplemented via environment
     # variables. This is better than setup.cfg files because it allows
     # supplementing configs instead of replacing them.
     extrapackages = os.environ.get('HG_PY2EXE_EXTRA_PACKAGES')
     if extrapackages:
         py2exepackages.extend(extrapackages.split(' '))
 
     excludes = os.environ.get('HG_PY2EXE_EXTRA_EXCLUDES')
     if excludes:
         py2exeexcludes.extend(excludes.split(' '))
 
     dllexcludes = os.environ.get('HG_PY2EXE_EXTRA_DLL_EXCLUDES')
     if dllexcludes:
         py2exedllexcludes.extend(dllexcludes.split(' '))
 
 if os.name == 'nt':
     # Windows binary file versions for exe/dll files must have the
     # form W.X.Y.Z, where W,X,Y,Z are numbers in the range 0..65535
     setupversion = setupversion.split(r'+', 1)[0]
 
 if sys.platform == 'darwin' and os.path.exists('/usr/bin/xcodebuild'):
     version = runcmd(['/usr/bin/xcodebuild', '-version'], {})[1].splitlines()
     if version:
         version = version[0]
         if sys.version_info[0] == 3:
             version = version.decode('utf-8')
         xcode4 = (version.startswith('Xcode') and
                   StrictVersion(version.split()[1]) >= StrictVersion('4.0'))
         xcode51 = re.match(r'^Xcode\s+5\.1', version) is not None
     else:
         # xcodebuild returns empty on OS X Lion with XCode 4.3 not
         # installed, but instead with only command-line tools. Assume
         # that only happens on >= Lion, thus no PPC support.
         xcode4 = True
         xcode51 = False
 
     # XCode 4.0 dropped support for ppc architecture, which is hardcoded in
     # distutils.sysconfig
     if xcode4:
         os.environ['ARCHFLAGS'] = ''
 
     # XCode 5.1 changes clang such that it now fails to compile if the
     # -mno-fused-madd flag is passed, but the version of Python shipped with
     # OS X 10.9 Mavericks includes this flag. This causes problems in all
     # C extension modules, and a bug has been filed upstream at
     # http://bugs.python.org/issue21244. We also need to patch this here
     # so Mercurial can continue to compile in the meantime.
     if xcode51:
         cflags = get_config_var('CFLAGS')
         if cflags and re.search(r'-mno-fused-madd\b', cflags) is not None:
             os.environ['CFLAGS'] = (
                 os.environ.get('CFLAGS', '') + ' -Qunused-arguments')
 
 setup(name='mercurial',
       version=setupversion,
       author='Matt Mackall and many others',
       author_email='[e-mail]',
       url='https://mercurial-scm.org/',
       download_url='https://mercurial-scm.org/release/',
       description=('Fast scalable distributed SCM (revision control, version '
                    'control) system'),
       long_description=('Mercurial is a distributed SCM tool written in Python.'
                         ' It is used by a number of large projects that require'
                         ' fast, reliable distributed revision control, such as '
                         'Mozilla.'),
       license='GNU GPLv2 or any later version',
       classifiers=[
           'Development Status :: 6 - Mature',
           'Environment :: Console',
           'Intended Audience :: Developers',
           'Intended Audience :: System Administrators',
           'License :: OSI Approved :: GNU General Public License (GPL)',
           'Natural Language :: Danish',
           'Natural Language :: English',
           'Natural Language :: German',
           'Natural Language :: Italian',
           'Natural Language :: Japanese',
           'Natural Language :: Portuguese (Brazilian)',
           'Operating System :: Microsoft :: Windows',
           'Operating System :: OS Independent',
           'Operating System :: POSIX',
           'Programming Language :: C',
           'Programming Language :: Python',
           'Topic :: Software Development :: Version Control',
       ],
       scripts=scripts,
       packages=packages,
       ext_modules=extmodules,
       data_files=datafiles,
       package_data=packagedata,
       cmdclass=cmdclass,
       distclass=hgdist,
       options={
           'py2exe': {
               'bundle_files': 3,
               'dll_excludes': py2exedllexcludes,
               'excludes': py2exeexcludes,
               'packages': py2exepackages,
           },
           'bdist_mpkg': {
               'zipdist': False,
               'license': 'COPYING',
               'readme': 'contrib/packaging/macosx/Readme.html',
               'welcome': 'contrib/packaging/macosx/Welcome.html',
           },
       },
       **extra)