hgext/fsmonitor/pywatchman/encoding.py

diff: make sure we output stat even when --git is not passed (issue4037) (BC)

Before this patch, `hg diff --stat` will give an empty output. It will not show
the stat information. I debugged and found that the underlying code does not
return the diff header and due to that, other code paths fails to parse that as
a diff.

I looked into why we don't return diff headers in quiet mode and found the
behavior is from 8f8bb77d560e70bcc95577e4dfa877df18d876ab which does not have
any mention about why it is done. We also show the diff headers in git, so I
think it's fine showing diff header in normal diff in quiet mode.

Differential Revision: https://phab.mercurial-scm.org/D6007

# Copyright 2016-present Facebook, Inc.
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from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
# no unicode literals

'''Module to deal with filename encoding on the local system, as returned by
Watchman.'''

import sys

from . import (
    compat,
)

if compat.PYTHON3:
    default_local_errors = 'surrogateescape'

    def get_local_encoding():
        if sys.platform == 'win32':
            # Watchman always returns UTF-8 encoded strings on Windows.
            return 'utf-8'
        # On the Python 3 versions we support, sys.getfilesystemencoding never
        # returns None.
        return sys.getfilesystemencoding()
else:
    # Python 2 doesn't support surrogateescape, so use 'strict' by
    # default. Users can register a custom surrogateescape error handler and use
    # that if they so desire.
    default_local_errors = 'strict'

    def get_local_encoding():
        if sys.platform == 'win32':
            # Watchman always returns UTF-8 encoded strings on Windows.
            return 'utf-8'
        fsencoding = sys.getfilesystemencoding()
        if fsencoding is None:
            # This is very unlikely to happen, but if it does, just use UTF-8
            fsencoding = 'utf-8'
        return fsencoding

def encode_local(s):
    return s.encode(get_local_encoding(), default_local_errors)

def decode_local(bs):
    return bs.decode(get_local_encoding(), default_local_errors)