view mercurial/txnutil.py @ 44746:c36a3fcfc36b stable

upgrade: properly filter action depending on planned work

The `determineactions` function filters out deficiency that are not scheduled to
be fixed by the target repository configuration. However it only did so for
requirement we currently support, letting other actions for unsupported
requirement through even if the target repo configuration did not request it.

As a result the output of the command was easily polluted by experimental
feature with no upgrade support.

We rework the code to still filter out requirement based action without the
faulty filtering.

Differential Revision: https://phab.mercurial-scm.org/D8427

# 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)