# obsutil.py - utility functions for obsolescence

#

# Copyright 2017 Boris Feld <boris.feld@octobus.net>

#

# 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

def closestpredecessors(repo, nodeid):

    """yield the list of next predecessors pointing on visible changectx nodes

    This function respect the repoview filtering, filtered revision will be

    considered missing.

    """

    precursors = repo.obsstore.precursors

    stack = [nodeid]

    seen = set(stack)

    while stack:

        current = stack.pop()

        currentpreccs = precursors.get(current, ())

        for prec in currentpreccs:

            precnodeid = prec[0]

            # Basic cycle protection

            if precnodeid in seen:

                continue

            seen.add(precnodeid)

            if precnodeid in repo:

                yield precnodeid

            else:

                stack.append(precnodeid)