def import_from_node()

in usort/translate.py [0:0]

• 34 lines of code
• 16 McCabe index (conditional complexity)

def import_from_node(node: cst.SimpleStatementLine, config: Config) -> SortableImport:
    # TODO: This duplicates (differently) what's in the LibCST import metadata visitor.

    stem: Optional[str] = None
    items: List[SortableImportItem] = []
    comments = import_comments_from_node(node)

    # There are 4 basic types of import
    # Additionally some forms z can have leading dots for relative
    # imports, and there can be multiple on the right-hand side.
    #
    if isinstance(node.body[0], cst.Import):
        # import z
        # import z as y
        items = [item_from_node(name) for name in node.body[0].names]

    elif isinstance(node.body[0], cst.ImportFrom):
        # from z import x
        # from z import x as y

        # This is treated as a barrier and should never get this far.
        assert not isinstance(node.body[0].names, cst.ImportStar)

        stem = with_dots(node.body[0].module) if node.body[0].module else ""

        if node.body[0].relative:
            stem = "." * len(node.body[0].relative) + stem

        for name in node.body[0].names:
            items.append(item_from_node(name, stem, comments.initial))
            comments.initial = []

    else:
        raise TypeError

    # assume that "following" comments are actually meant for an item after that
    prev: Optional[SortableImportItem] = None
    for item in items:
        if prev is not None and prev.comments.following:
            item.comments.before.extend(prev.comments.following)
            prev.comments.following.clear()
        prev = item
    # following comments on the last item should maybe be on the import itself
    if prev is not None and prev.comments.following:
        comments.final.extend(prev.comments.following)
        prev.comments.following.clear()

    imp = SortableImport(
        stem=stem,
        items=items,
        comments=comments,
        config=config,
        node=node,
        indent="",
    )
    return imp