view mercurial/txnutil.py @ 33276:89796a25d4bb

template: add successors template

Add a 'successorssets' template that returns the list of all closest known
sucessorssets for a changectx. The elements of the list are changesets.

The "closest successors" are the first locally known revisions encountered
while, walking successors markers. It uses successorsets previously modified
to support the closest argument.

This logic respect repository filtering. So hidden revision will be skipped by
this logic unless --hidden is specified. Since we only display the visible
predecessors, this template will not display anything in most case. It makes a
good candidate for inclusion in the default log output.

I updated the test-obsmarker-template.t test file introduced with the
predecessors template to test successorssets template.

# 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)