setup.py

sparse-revlog: set max delta chain length to on thousand

The new snapshot system used in the sparse-revlog case gave us some small size
benefit so far. However its most important property is to gracefully handle
harder limit on delta chainlength.

Long delta chain has a very detrimental impact on read (and write) performance
in revlog. Being able to shorter them provide a great boost. However, shorting
delta used to result significantly lower compression ratio. The intermediate
snapshots effectively suppress most of this effect (even all in some case).

# Effect on the test repository

The repository we use for test is not "realistic" but can still show this in
action using an unreasonably low chain limit. Limiting the chain length show a
sizeable increase but stay under control: +6% for limit=15; +15% for limit=10.
Without the snapshot system the increase is significantly bigger: +45% for
limit=15; +80% for limit=10. Even slightly larger than without delta chain
limit, the resulting size is still smaller than before we started doing
snapshots.

Here is a table for comparison. *Since the repository is not branchy, the
initial sparse-revlog version does not bring much benefit compare to the
non-sparse one):

       chain length limit |     none   |   limit=15  |   limit=10  |
    without sparse-revlog | 62 818 987 | 112 664 615 | 131 222 574 |
    without snapshot      | 74 365 490 | 108 211 410 | 133 857 764 |
    with    snapshot      | 59 230 936 |  63 002 924 |  68 415 329 |


# Effect On Real Life Repositories

The series provides significant benefits on all kind of repositories.

Using `hg debugupgraderepo -o redeltaparent --run`, we recomputed delta chain
for various repositories with different settings:
  - delta chain length: unlimited or 1000 limit
  - sparse-revlog:      enabled or disabled
  - this series:        applied or not applied

We can observe multiple types of effect:

 - On very branchy repositories:
   * The delta chain limit as low impact on the repo size.
   * Intermediate snapshot greatly reduces manifest size:
     - pypy:     -80%
     - netbeans: -95%
   * The delta chain limit is effective, without a size impact:
     - netbeans average:      613 -> 282
     - private #1 average:  1 068 -> 307

 - On more linear repository:
   * Intermediate snapshot limit the impact of delta chain limit:
     - mozilla:
         without the series: +360%
         with the series:     +25%
   * The delta chain limit provides large improvement:
     - mozilla's average chain length:
        unlimited: 15 338
        limited:      469
   * Despite the chain length limit, the manifest size is reduced:
     - mercurial: -25%
     - mozilla:   -30%

It is clear that the use of chains of intermediate snapshots provide large
benefits both in storage size and delta chains quality. We should now switch our
effort toward making sure the write performance are acceptable. Then,
`sparse-revlog` will be a suitable format for all new repository.

# Raw Statistic

  * no-sparse:   general delta repository not using sparse-revlog
  * no-snapshot: sparse-revlog repository not using this series
  * snapshot:    sparse-revlog repository using this series

mercurial

    Manifest Size:
        limit       | none        |        1000
        ------------|-------------|------------
        no-sparse   |   8 021 373 |  8 199 366
        no-snapshot |   8 103 561 |  8 259 719
        snapshot    |   6 137 116 |  6 126 433

    Manifest Chain length data
        limit       ||       none        ||       1000        ||
        value       || average |   max   || average |   max   ||
        ------------||---------|---------||---------|---------||
        no-sparse   ||     307 |    1456 ||     279 |    1000 ||
        no-snapshot ||     312 |    1456 ||     283 |    1000 ||
        snapshot    ||     248 |    1208 ||     241 |    1000 ||

    Full Store Size
        limit       | none        |        1000
        ------------|-------------|------------
        no-sparse   |  51 013 198 | 51 201 574
        no-snapshot |  50 930 795 | 51 141 006
        snapshot    |  48 072 037 | 48 093 572

pypy

    Manifest Size:
        limit       | none        |        1000
        ------------|-------------|------------
        no-sparse   | 193 987 784 | 193 987 784
        no-snapshot | 163 171 745 | 163 312 229
        snapshot    |  34 605 900 |  34 600 750

    Manifest Chain length data
        limit       ||       none        ||       1000        ||
        value       || average |   max   || average |   max   ||
        ------------||---------|---------||---------|---------||
        no-sparse   ||     101 |     692 ||     101 |     692 ||
        no-snapshot ||     151 |    1307 ||     148 |    1000 ||
        snapshot    ||     128 |    1309 ||     125 |    1000 ||

    Full Store Size
        limit       | none        |        1000
        ------------|-------------|------------
        no-sparse   | 495 931 473 | 495 931 473
        no-snapshot | 465 441 017 | 465 581 501
        snapshot    | 355 467 301 | 355 472 451

Mozilla

    Manifest Size:
        limit       | none           |        1000
        ------------|----------------|---------------
        no-sparse   |    416 757 148 |  1 869 009 668
        no-snapshot |    401 592 370 |  1 843 493 795
        snapshot    |    224 359 521 |    284 615 500

    Manifest Chain length data
        limit       ||       none        ||       1000        ||
        value       || average |   max   || average |   max   ||
        ------------||---------|---------||---------|---------||
        no-sparse   ||  15 333 |  58 980 ||     468 |   1 000 ||
        no-snapshot ||  15 336 |  58 980 ||     469 |   1 000 ||
        snapshot    ||  15 338 |  58 983 ||     469 |   1 000 ||

    Full Store Size
        limit       | none           |        1000
        ------------|----------------|---------------
        no-sparse   |  2 712 477 887 | 4 164 995 451
        no-snapshot |  2 698 887 835 | 4 141 054 304
        snapshot    |  2 518 130 385 | 2 578 587 596

Netbeans

    Manifest Size:
        limit       | none           |        1000
        ------------|----------------|---------------
        no-sparse   |  4 766 794 101 |  4 870 642 687
        no-snapshot |  4 334 806 082 |  4 428 681 309
        snapshot    |    232 659 666 |    240 330 665

    Manifest Chain length data
        limit       ||       none        ||       1000        ||
        value       || average |   max   || average |   max   ||
        ------------||---------|---------||---------|---------||
        no-sparse   ||     597 |   6802  ||     254 |   1 000 ||
        no-snapshot ||     648 |   6 802 ||     305 |   1 000 ||
        snapshot    ||     613 |   6 804 ||     282 |   1 000 ||

    Full Store Size
        limit       | none           |        1000
        ------------|----------------|---------------
        no-sparse   |  5 807 347 998 |  5 911 196 584
        no-snapshot |  5 375 398 602 |  5 469 273 829
        snapshot    |  1 282 519 928 |  1 290 190 927

Private repo #1

    Manifest Size:
        limit       | none            |        1000
        ------------|-----------------|---------------
        no-sparse   | 41 389 010 840  | 41 398 162 091
        no-snapshot |  9 737 319 435  | 10 223 773 150
        snapshot    |    744 215 807  |    747 961 822

    Manifest Chain length data
        limit       ||       none        ||       1000        ||
        value       || average |   max   || average |   max   ||
        ------------||---------|---------||---------|---------||
        no-sparse   ||     245 |   8 885 ||     81  |   1 000 ||
        no-snapshot ||   1 225 |   8 885 ||    336  |   1 000 ||
        snapshot    ||   1 068 |   7 909 ||    307  |   1 000 ||

    Full Store Size
        limit       | none           |        1000
        ------------|----------------|---------------
        no-sparse   | 49 646 065 126 | 49 655 216 377
        no-snapshot | 17 924 862 856 | 18 411 316 571
        snapshot    |  9 009 024 710 |  9 012 770 725

Private repo #2

  We currently have less data available for that repository.
    * Before is a sparse-revlog repository without this series
    * After is a sparse-revlog repository with this series + 1000 chain limit


  Manifest Size:
    Before: 1 531 485 040 bytes
    After:  1 091 422 451 bytes
  Manifest Chain:
    Before: 2 218 avg; 6 575 Max
    After:    442 avg; 1 000 Max

  Full Store Size
    Before: 15 203 955 615
    after:   8 207 180 693

#
# 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.
    #
    # 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.*',
        '!=3.6.0',
        '!=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 = """
Mercurial only supports Python 2.7.
Python {py} detected.
Please re-run with Python 2.7.
""".format(py=sys.version_info)

        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

import ctypes
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

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):
    p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE, env=env)
    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:'))]
    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.
    check_cmd = ['log', '-r.', '-Ttest']
    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):
        # Filter out zstd if disabled via argument.
        if not self.zstd:
            self.extensions = [e for e in self.extensions
                               if e.name != 'mercurial.zstd']

        return build_ext.build_extensions(self)

    def build_extension(self, ext):
        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'
        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, 'w') as f:
            f.write('# this file is autogenerated by setup.py\n')
            f.write('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('.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('/* this file is autogenerated by setup.py */\n')
            f.write('#define HGPYTHONLIB "%s"\n' % pythonlib)
        objects = self.compiler.compile(['mercurial/exewrapper.c'],
                                         output_dir=self.build_temp)
        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):
        """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 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)

cmdclass = {'build': hgbuild,
            '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,
            }

packages = ['mercurial',
            'mercurial.cext',
            'mercurial.cffi',
            'mercurial.hgweb',
            'mercurial.pure',
            'mercurial.thirdparty',
            'mercurial.thirdparty.attr',
            'mercurial.thirdparty.cbor',
            'mercurial.thirdparty.cbor.cbor2',
            'mercurial.thirdparty.concurrent',
            'mercurial.thirdparty.concurrent.futures',
            'mercurial.thirdparty.zope',
            'mercurial.thirdparty.zope.interface',
            'mercurial.utils',
            'mercurial.revlogutils',
            'hgext', 'hgext.convert', 'hgext.fsmonitor',
            'hgext.fastannotate',
            'hgext.fsmonitor.pywatchman',
            'hgext.infinitepush',
            'hgext.highlight',
            'hgext.largefiles', 'hgext.lfs', 'hgext.narrow',
            'hgext.zeroconf', 'hgext3rd',
            'hgdemandimport']

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',
]

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),
    Extension('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'],
              include_dirs=common_include_dirs,
              depends=common_depends + ['mercurial/cext/charencode.h']),
    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']),
    ]

sys.path.insert(0, 'contrib/python-zstandard')
import setup_zstd
extmodules.append(setup_zstd.get_c_extension(name='mercurial.zstd'))

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 = {}

if issetuptools:
    extra['python_requires'] = supportedpy
if py2exeloaded:
    extra['console'] = [
        {'script':'hg',
         'copyright':'Copyright (C) 2005-2018 Matt Mackall and others',
         'product_version':version}]
    # sub command of 'build' because 'py2exe' does not handle sub_commands
    build.sub_commands.insert(0, ('build_hgextindex', None))
    # put dlls in sub directory so that they won't pollute PATH
    extra['zipfile'] = 'lib/library.zip'

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 = version.split('+', 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': {
              'packages': [
                  'hgdemandimport',
                  'hgext',
                  'email',
                  # implicitly imported per module policy
                  # (cffi wouldn't be used as a frozen exe)
                  'mercurial.cext',
                  #'mercurial.cffi',
                  'mercurial.pure',
              ],
          },
          'bdist_mpkg': {
              'zipdist': False,
              'license': 'COPYING',
              'readme': 'contrib/packaging/macosx/Readme.html',
              'welcome': 'contrib/packaging/macosx/Welcome.html',
          },
      },
      **extra)