annotate setup.py @ 42670:a7f1a0b3f461

module-policy: update rust extension import to use the new module policy

Differential Revision: https://phab.mercurial-scm.org/D6677

#
# 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
import sysconfig
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    pip_message = ('This may be due to an out of date pip.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                'Your pip version is out of date, please install '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)

if sys.version_info[0] >= 3:
    DYLIB_SUFFIX = sysconfig.get_config_vars()['EXT_SUFFIX']
else:
    # deprecated in Python 3
    DYLIB_SUFFIX = sysconfig.get_config_vars()['SO']

# 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
    rust = hgrustext is not None
    cffi = ispypy

    global_options = Distribution.global_options + [
        ('pure', None, "use pure (slow) Python code instead of C extensions"),
        ('rust', None, "use Rust extensions additionally to 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'
buildextnegops['no-rust'] = 'rust'

class hgbuildext(build_ext):
    user_options = build_ext.user_options + [
        ('zstd', None, 'compile zstd bindings [default]'),
        ('no-zstd', None, 'do not compile zstd bindings'),
        ('rust', None,
         'compile Rust extensions if they are in use '
         '(requires Cargo) [default]'),
        ('no-rust', None, 'do not compile Rust extensions'),
    ]

    boolean_options = build_ext.boolean_options + ['zstd', 'rust']
    negative_opt = buildextnegops

    def initialize_options(self):
        self.zstd = True
        self.rust = 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']

        # Build Rust standalon extensions if it'll be used
        # and its build is not explictely disabled (for external build
        # as Linux distributions would do)
        if self.distribution.rust and self.rust and hgrustext != 'direct-ffi':
            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 (self.distribution.rust and self.rust
            and 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)

        rust = self.distribution.rust
        if self.distribution.pure:
            modulepolicy = 'py'
        elif self.build_lib == '.':
            # in-place build should run without rebuilding and Rust extensions
            modulepolicy = 'rust+c-allow' if rust else 'allow'
        else:
            modulepolicy = 'rust+c' if rust else '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)
        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')

    @staticmethod
    def rustdylibsuffix():
        """Return the suffix for shared libraries produced by rustc.

        See also: https://doc.rust-lang.org/reference/linkage.html
        """
        if sys.platform == 'darwin':
            return '.dylib'
        elif os.name == 'nt':
            return '.dll'
        else:
            return '.so'

    def rustbuild(self):
        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', 'rustc', '-vv', '--release']
        if sys.version_info[0] == 3 and self.py3_features is not None:
            cargocmd.extend(('--features', self.py3_features,
                             '--no-default-features'))
        cargocmd.append('--')
        if sys.platform == 'darwin':
            cargocmd.extend(("-C", "link-arg=-undefined",
                             "-C", "link-arg=dynamic_lookup"))
        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)

    def rustbuild(self):
        if hgrustext == 'direct-ffi':
            RustExtension.rustbuild(self)

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('.'))
        target[-1] += DYLIB_SUFFIX
        shutil.copy2(os.path.join(self.rusttargetdir,
                                  self.dylibname + self.rustdylibsuffix()),
                     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']),
    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)