view mercurial/txnutil.py @ 32405:bdc4861ffe59

fsmonitor: fix silly "*kwargs" bug in merge.update() override

Everyone knows that it's supposed to be spelled with two asterisks.

It started failing in fad5e299cfc7 (update: accept --merge to allow
merging across topo branches (issue5125), 2017-02-13) because until
then there was only one argument that was covered by the kwargs, so
*kwargs or **kwargs both worked (or at least that's what I think with
my limited understanding of Python).

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import errno

from . import (
    encoding,
)

def mayhavepending(root):
    '''return whether 'root' may have pending changes, which are
    visible to this process.
    '''
    return root == encoding.environ.get('HG_PENDING')

def trypending(root, vfs, filename, **kwargs):
    '''Open  file to be read according to HG_PENDING environment variable

    This opens '.pending' of specified 'filename' only when HG_PENDING
    is equal to 'root'.

    This returns '(fp, is_pending_opened)' tuple.
    '''
    if mayhavepending(root):
        try:
            return (vfs('%s.pending' % filename, **kwargs), True)
        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise
    return (vfs(filename, **kwargs), False)