view mercurial/scmwindows.py @ 45047:40120de810ba stable

demandimport: ignore `lzma` module for demandimport

This makes importing the module fail if the `_lzma` module is not present.

This makes e.g. tarfile correctly recognize if LZMA support is not present. It
changes the exception

    File "/usr/lib/python3.6/tarfile.py", line 1694, in xzopen
      fileobj = lzma.LZMAFile(fileobj or name, mode, preset=preset)
  AttributeError: module 'lzma' has no attribute 'LZMAFile'

to the more correct exception

    File "/usr/lib/python3.6/tarfile.py", line 1692, in xzopen
      raise CompressionError("lzma module is not available")
  tarfile.CompressionError: lzma module is not available

Also, it prevents that the error "abort: No module named '_lzma'!" is shown when
a development warning is to be shown. The reason why that happened is that for
showing the warning, we get information about the stack frames from the inspect
module, which accesses the `__file__` attribute of all modules in `sys.modules`
to build some cache, causing all modules (including `lzma`) to be imported.

from __future__ import absolute_import

import os

from . import (
    encoding,
    pycompat,
    util,
    win32,
)

try:
    import _winreg as winreg  # pytype: disable=import-error

    winreg.CloseKey
except ImportError:
    # py2 only
    import winreg  # pytype: disable=import-error

# MS-DOS 'more' is the only pager available by default on Windows.
fallbackpager = b'more'


def systemrcpath():
    '''return default os-specific hgrc search path'''
    rcpath = []
    filename = win32.executablepath()
    # Use mercurial.ini found in directory with hg.exe
    progrc = os.path.join(os.path.dirname(filename), b'mercurial.ini')
    rcpath.append(progrc)

    def _processdir(progrcd):
        if os.path.isdir(progrcd):
            for f, kind in util.listdir(progrcd):
                if f.endswith(b'.rc'):
                    rcpath.append(os.path.join(progrcd, f))

    # Use hgrc.d found in directory with hg.exe
    _processdir(os.path.join(os.path.dirname(filename), b'hgrc.d'))

    # treat a PROGRAMDATA directory as equivalent to /etc/mercurial
    programdata = encoding.environ.get(b'PROGRAMDATA')
    if programdata:
        programdata = os.path.join(programdata, b'Mercurial')
        _processdir(os.path.join(programdata, b'hgrc.d'))

        ini = os.path.join(programdata, b'mercurial.ini')
        if os.path.isfile(ini):
            rcpath.append(ini)

        ini = os.path.join(programdata, b'hgrc')
        if os.path.isfile(ini):
            rcpath.append(ini)

    # next look for a system rcpath in the registry
    value = util.lookupreg(
        b'SOFTWARE\\Mercurial', None, winreg.HKEY_LOCAL_MACHINE
    )
    if value and isinstance(value, bytes):
        value = util.localpath(value)
        for p in value.split(pycompat.ospathsep):
            if p.lower().endswith(b'mercurial.ini'):
                rcpath.append(p)
            else:
                _processdir(p)
    return rcpath


def userrcpath():
    '''return os-specific hgrc search path to the user dir'''
    home = os.path.expanduser(b'~')
    path = [os.path.join(home, b'mercurial.ini'), os.path.join(home, b'.hgrc')]
    userprofile = encoding.environ.get(b'USERPROFILE')
    if userprofile and userprofile != home:
        path.append(os.path.join(userprofile, b'mercurial.ini'))
        path.append(os.path.join(userprofile, b'.hgrc'))
    return path


def termsize(ui):
    return win32.termsize()