Function parse_mode

src/blackd/__init__.py:246–294

(headers: MultiMapping[str])

def parse_mode(headers: MultiMapping[str]) -> black.Mode:
    try:
        line_length = int(headers.get(LINE_LENGTH_HEADER, black.DEFAULT_LINE_LENGTH))
    except ValueError:
        raise HeaderError("Invalid line length header value") from None

    if PYTHON_VARIANT_HEADER in headers:
        value = headers[PYTHON_VARIANT_HEADER]
        try:
            pyi, versions = parse_python_variant_header(value)
        except InvalidVariantHeader as e:
            raise HeaderError(
                f"Invalid value for {PYTHON_VARIANT_HEADER}: {e.args[0]}",
            ) from None
    else:
        pyi = False
        versions = set()

    skip_string_normalization = bool(
        headers.get(SKIP_STRING_NORMALIZATION_HEADER, False)
    )
    skip_magic_trailing_comma = bool(headers.get(SKIP_MAGIC_TRAILING_COMMA, False))
    skip_source_first_line = bool(headers.get(SKIP_SOURCE_FIRST_LINE, False))

    preview = bool(headers.get(PREVIEW, False))
    unstable = bool(headers.get(UNSTABLE, False))
    enable_features: set[black.Preview] = set()
    enable_unstable_features = headers.get(ENABLE_UNSTABLE_FEATURE, "").split(",")
    for piece in enable_unstable_features:
        piece = piece.strip()
        if piece:
            try:
                enable_features.add(black.Preview[piece])
            except KeyError:
                raise HeaderError(
                    f"Invalid value for {ENABLE_UNSTABLE_FEATURE}: {piece}",
                ) from None

    return black.FileMode(
        target_versions=versions,
        is_pyi=pyi,
        line_length=line_length,
        skip_source_first_line=skip_source_first_line,
        string_normalization=not skip_string_normalization,
        magic_trailing_comma=not skip_magic_trailing_comma,
        preview=preview,
        unstable=unstable,
        enabled_features=enable_features,
    )


def parse_python_variant_header(value: str) -> tuple[bool, set[black.TargetVersion]]: