evolve: abort if deciding resolution parent is ambiguous While solving content-divergence, it could be hard to decide which cset should be treated as a resolution parent if there are multiple successors of divergent cset. i.e split case. But we are planning to make some update in handling this split case: 1) consider highest one if all splitted csets are in a single topological branch 2) still need to decide if 1) doesn't apply

import hghave

@hghave.check("docgraph-ext", "Extension to generate graph from repository")
def docgraph():
    try:
        import hgext.docgraph
        hgext.docgraph.cmdtable # trigger import
    except ImportError:
        try:
            import hgext3rd.docgraph
            hgext3rd.docgraph.cmdtable # trigger import
        except ImportError:
            return False
    return True