mercurial/obsutil.py

check-concurrency: expose the feature as 'concurrent-push-mode'

We move the feature to a proper configuration and document it. The config goes
in the 'server' section because it feels like something the server owner would
want to decide. We pick and open field because it seems likely that other
checking levels will emerge in the future. (eg: server like the mozilla-try
server will likely wants a "none" value)

The option name contains 'push' since this affects 'push' only. The option value
'check-related' is preferred over one explicitly containing 'allow' or 'deny'
because the client still have a strong decision power here. Here, the server is
just advising the client on the check mode to use.

# obsutil.py - utility functions for obsolescence
#
# Copyright 2017 Boris Feld <[e-mail]>
#
# 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)