mercurial/scmposix.py

help: show "[no-]" only for default-on Flags

As Anton (av6) pointed out, the "[no-]" is confusing for action flags
like `hg bookmark --delete`. We could come up with a way of indicating
which flags are action flags (e.g. use None for the default value
instead of False). However, it's probably also unlikely that users
will want to negate even non-action flags like --hidden.

One of the more common flags where the "[no-]" prefix would be useful
is `hg evolve --update`. The reason it's helpful there is that it
defaults to on. So I think we can simply include "[no-]" only for
flags that are on by default (and thus require the user to add the
"[no-]" for the option to have any effect).

Note that there are use cases for negating flags that already off by
default. For example, you may have an alias for `hg log -G --hidden -T
foo` and now want to pass "--no-hidden" to that alias. However, I
think that users who want that are likely to be advanced enough that
they've already learnt about the "no-" prefix by seeing it somewhere
else.

Differential Revision: https://phab.mercurial-scm.org/D5454

from __future__ import absolute_import

import array
import errno
import fcntl
import os
import sys

from . import (
    encoding,
    pycompat,
    util,
)

# BSD 'more' escapes ANSI color sequences by default. This can be disabled by
# $MORE variable, but there's no compatible option with Linux 'more'. Given
# OS X is widely used and most modern Unix systems would have 'less', setting
# 'less' as the default seems reasonable.
fallbackpager = 'less'

def _rcfiles(path):
    rcs = [os.path.join(path, 'hgrc')]
    rcdir = os.path.join(path, 'hgrc.d')
    try:
        rcs.extend([os.path.join(rcdir, f)
                    for f, kind in util.listdir(rcdir)
                    if f.endswith(".rc")])
    except OSError:
        pass
    return rcs

def systemrcpath():
    path = []
    if pycompat.sysplatform == 'plan9':
        root = 'lib/mercurial'
    else:
        root = 'etc/mercurial'
    # old mod_python does not set sys.argv
    if len(getattr(sys, 'argv', [])) > 0:
        p = os.path.dirname(os.path.dirname(pycompat.sysargv[0]))
        if p != '/':
            path.extend(_rcfiles(os.path.join(p, root)))
    path.extend(_rcfiles('/' + root))
    return path

def userrcpath():
    if pycompat.sysplatform == 'plan9':
        return [encoding.environ['home'] + '/lib/hgrc']
    elif pycompat.isdarwin:
        return [os.path.expanduser('~/.hgrc')]
    else:
        confighome = encoding.environ.get('XDG_CONFIG_HOME')
        if confighome is None or not os.path.isabs(confighome):
            confighome = os.path.expanduser('~/.config')

        return [os.path.expanduser('~/.hgrc'),
                os.path.join(confighome, 'hg', 'hgrc')]

def termsize(ui):
    try:
        import termios
        TIOCGWINSZ = termios.TIOCGWINSZ  # unavailable on IRIX (issue3449)
    except (AttributeError, ImportError):
        return 80, 24

    for dev in (ui.ferr, ui.fout, ui.fin):
        try:
            try:
                fd = dev.fileno()
            except AttributeError:
                continue
            if not os.isatty(fd):
                continue
            arri = fcntl.ioctl(fd, TIOCGWINSZ, '\0' * 8)
            height, width = array.array(r'h', arri)[:2]
            if width > 0 and height > 0:
                return width, height
        except ValueError:
            pass
        except IOError as e:
            if e[0] == errno.EINVAL:
                pass
            else:
                raise
    return 80, 24