view mercurial/txnutil.py @ 47765:184d83ef2e59 stable

tests: demonstrate bug in `hg fix` with incorrectly dirty working copy

If the parent commit needs formatting but the working copy already has
the correct formatting, then the working copy will be reported as
modified even though it's clean (because the size in the dirstate is
incorrect). Because the bug only occurs when the size changes, I
modified the formatter used in the test case to remove repeated
spaces.

Differential Revision: https://phab.mercurial-scm.org/D11208

# 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)