comparison mercurial/obsutil.py @ 33143:d09ae850296d

obsutil: move 'exclusivemarkers' to the new modules

We have a new 'obsutil' module now. We move the high level utility there to
bring 'obsolete.py' back to a more reasonable size.

33142:4f49810a1011

            if precnodeid in repo:
                yield precnodeid
            else:
                stack.append(precnodeid)

def successorssets(repo, initialnode, cache=None):
    """Return set of all latest successors of initial nodes

    The successors set of a changeset A are the group of revisions that succeed

33143:d09ae850296d

            if precnodeid in repo:
                yield precnodeid
            else:
                stack.append(precnodeid)

def _filterprunes(markers):
    """return a set with no prune markers"""
    return set(m for m in markers if m[1])

def exclusivemarkers(repo, nodes):
    """set of markers relevant to "nodes" but no other locally-known nodes

    This function compute the set of markers "exclusive" to a locally-known
    node. This means we walk the markers starting from <nodes> until we reach a
    locally-known precursors outside of <nodes>. Element of <nodes> with
    locally-known successors outside of <nodes> are ignored (since their
    precursors markers are also relevant to these successors).

    For example:

        # (A0 rewritten as A1)
        #
        # A0 <-1- A1 # Marker "1" is exclusive to A1

        or

        # (A0 rewritten as AX; AX rewritten as A1; AX is unkown locally)
        #
        # <-1- A0 <-2- AX <-3- A1 # Marker "2,3" are exclusive to A1

        or

        # (A0 has unknown precursors, A0 rewritten as A1 and A2 (divergence))
        #
        #          <-2- A1 # Marker "2" is exclusive to A0,A1
        #        /
        # <-1- A0
        #        \
        #         <-3- A2 # Marker "3" is exclusive to A0,A2
        #
        # in addition:
        #
        #  Markers "2,3" are exclusive to A1,A2
        #  Markers "1,2,3" are exclusive to A0,A1,A2

        See test/test-obsolete-bundle-strip.t for more examples.

    An example usage is strip. When stripping a changeset, we also want to
    strip the markers exclusive to this changeset. Otherwise we would have
    "dangling"" obsolescence markers from its precursors: Obsolescence markers
    marking a node as obsolete without any successors available locally.

    As for relevant markers, the prune markers for children will be followed.
    Of course, they will only be followed if the pruned children is
    locally-known. Since the prune markers are relevant to the pruned node.
    However, while prune markers are considered relevant to the parent of the
    pruned changesets, prune markers for locally-known changeset (with no
    successors) are considered exclusive to the pruned nodes. This allows
    to strip the prune markers (with the rest of the exclusive chain) alongside
    the pruned changesets.
    """
    # running on a filtered repository would be dangerous as markers could be
    # reported as exclusive when they are relevant for other filtered nodes.
    unfi = repo.unfiltered()

    # shortcut to various useful item
    nm = unfi.changelog.nodemap
    precursorsmarkers = unfi.obsstore.precursors
    successormarkers = unfi.obsstore.successors
    childrenmarkers = unfi.obsstore.children

    # exclusive markers (return of the function)
    exclmarkers = set()
    # we need fast membership testing
    nodes = set(nodes)
    # looking for head in the obshistory
    #
    # XXX we are ignoring all issues in regard with cycle for now.
    stack = [n for n in nodes if not _filterprunes(successormarkers.get(n, ()))]
    stack.sort()
    # nodes already stacked
    seennodes = set(stack)
    while stack:
        current = stack.pop()
        # fetch precursors markers
        markers = list(precursorsmarkers.get(current, ()))
        # extend the list with prune markers
        for mark in successormarkers.get(current, ()):
            if not mark[1]:
                markers.append(mark)
        # and markers from children (looking for prune)
        for mark in childrenmarkers.get(current, ()):
            if not mark[1]:
                markers.append(mark)
        # traverse the markers
        for mark in markers:
            if mark in exclmarkers:
                # markers already selected
                continue

            # If the markers is about the current node, select it
            #
            # (this delay the addition of markers from children)
            if mark[1] or mark[0] == current:
                exclmarkers.add(mark)

            # should we keep traversing through the precursors?
            prec = mark[0]

            # nodes in the stack or already processed
            if prec in seennodes:
                continue

            # is this a locally known node ?
            known = prec in nm
            # if locally-known and not in the <nodes> set the traversal
            # stop here.
            if known and prec not in nodes:
                continue

            # do not keep going if there are unselected markers pointing to this
            # nodes. If we end up traversing these unselected markers later the
            # node will be taken care of at that point.
            precmarkers = _filterprunes(successormarkers.get(prec))
            if precmarkers.issubset(exclmarkers):
                seennodes.add(prec)
                stack.append(prec)

    return exclmarkers

def successorssets(repo, initialnode, cache=None):
    """Return set of all latest successors of initial nodes

    The successors set of a changeset A are the group of revisions that succeed