view mercurial/txnutil.py @ 33196:439b4d005b4a

tests: demonstrate inconsistencies with dirty state in various commands

Not only is the output of these commands inconsistent with respect to each
other when a file is deleted, they are internally inconsistent depending upon
whether the deleted file is in the top level repo or a subrepo.  It seemed
easier to show the problems, rather than describe them.  The original goal was
to fix the summary command with respect to deleted files.  I haven't fixed any
of the other issues yet, in case anybody believes the current subrepo behavior
is correct.

I think a natural understanding of clean/dirty is that they are two opposite
values of a single binary repo state.  If `hg update --clean -r .` changes a
file, then naturally that repo was dirty, and `hg update --check` should have
blocked it.  Deleted files are special, in that they don't block a commit.  But
they make the filesystem content not the same as a clean checkout.

# 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)