Function _rhs

src/black/linegen.py:759–784

Wraps calls to `right_hand_split`. The calls increasingly `omit` right-hand trailers (bracket pairs with content), meaning the trailers get glued together to split on another bracket pair instead.

(
            self: object, line: Line, features: Collection[Feature], mode: Mode
        )

    else:

        def _rhs(
            self: object, line: Line, features: Collection[Feature], mode: Mode
        ) -> Iterator[Line]:
            """Wraps calls to `right_hand_split`.

            The calls increasingly `omit` right-hand trailers (bracket pairs with
            content), meaning the trailers get glued together to split on another
            bracket pair instead.
            """
            for omit in generate_trailers_to_omit(line, mode.line_length):
                lines = list(right_hand_split(line, mode, features, omit=omit))
                # Note: this check is only able to figure out if the first line of the
                # *current* transformation fits in the line length.  This is true only
                # for simple cases.  All others require running more transforms via
                # `transform_line()`.  This check doesn't know if those would succeed.
                if is_line_short_enough(lines[0], mode=mode) or (
                    omit and _over_length_only_due_to_subscript_comment(lines[0], mode)
                ):
                    yield from lines
                    return

            # All splits failed, best effort split with no omits.
            # This mostly happens to multiline strings that are by definition
            # reported as not fitting a single line, as well as lines that contain
            # trailing commas (those have to be exploded).
            yield from right_hand_split(line, mode, features=features)

        # HACK: nested functions (like _rhs) compiled by mypyc don't retain their
        # __name__ attribute which is needed in `run_transformer` further down.