view mercurial/txnutil.py @ 45085:a0192a03216d

rebase: remove now unnecessary logic to allow empty commit when branch changes

This was a workaround for a bug in the empty commit check in repo.commit(),
where the parent branch name was incorrectly compared with the wdir branch name
instead of the branch name passed via `extra`. The bug was fixed in D8724.

The workaround was introduced in b2415e94b2f5.

Differential Revision: https://phab.mercurial-scm.org/D8725

# 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(b'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(b'%s.pending' % filename, **kwargs), True)
        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise
    return (vfs(filename, **kwargs), False)