Function sort_as_subsets

lib/sqlalchemy/util/topological.py:30–55

(
    tuples: Collection[Tuple[_T, _T]], allitems: Collection[_T]
)

def sort_as_subsets(
    tuples: Collection[Tuple[_T, _T]], allitems: Collection[_T]
) -> Iterator[Sequence[_T]]:
    edges: DefaultDict[_T, Set[_T]] = util.defaultdict(set)
    for parent, child in tuples:
        edges[child].add(parent)

    todo = list(allitems)
    todo_set = set(allitems)

    while todo_set:
        output = []
        for node in todo:
            if todo_set.isdisjoint(edges[node]):
                output.append(node)

        if not output:
            raise CircularDependencyError(
                "Circular dependency detected.",
                find_cycles(tuples, allitems),
                _gen_edges(edges),
            )

        todo_set.difference_update(output)
        todo = [t for t in todo if t in todo_set]
        yield output


def sort(