Repository: psf/black
File: src/black/mode.py (Python)

Code before:
    string_normalization: bool = True
    is_pyi: bool = False
    is_ipynb: bool = False
    magic_trailing_comma: bool = True
    experimental_string_processing: bool = False
    preview: bool = False

    def __post_init__(self) -> None:
        if self.experimental_string_processing:
            warn(
                "`experimental string processing` has been included in `preview`"
                " and deprecated. Use `preview` instead.",
                Deprecated,
            )

    def __contains__(self, feature: Preview) -> bool:
        """
        Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.

        The argument is not checked and features are not differentiated.
        They only exist to make development easier by clarifying intent.
        """
        if feature is Preview.string_processing:
            return self.preview or self.experimental_string_processing
        return self.preview

    def get_cache_key(self) -> str:
        if self.target_versions:
            version_str = ",".join(
                str(version.value)
                for version in sorted(self.target_versions, key=attrgetter("value"))
            )
        else:
            version_str = "-"
        parts = [
            version_str,
            str(self.line_length),
            str(int(self.string_normalization)),
            str(int(self.is_pyi)),
            str(int(self.is_ipynb)),
            str(int(self.magic_trailing_comma)),
            str(int(self.experimental_string_processing)),
            str(int(self.preview)),
        ]
        return ".".join(parts)


Review comment (suggestion):
Looks like mypy (correctly) detects that this line is unreachable. Maybe to satisfy it we can add a feature we know we'll add to `--preview`, such as power operand hugging.

Code after:
    line_length: int = DEFAULT_LINE_LENGTH
    string_normalization: bool = True
    is_pyi: bool = False
    is_ipynb: bool = False
    magic_trailing_comma: bool = True
    experimental_string_processing: bool = False
    preview: bool = False

    def __post_init__(self) -> None:
        if self.experimental_string_processing:
            warn(
                "`experimental string processing` has been included in `preview`"
                " and deprecated. Use `preview` instead.",
                Deprecated,
            )

    def __contains__(self, feature: Preview) -> bool:
        """
        Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.

        The argument is not checked and features are not differentiated.
        They only exist to make development easier by clarifying intent.
        """
        if feature is Preview.string_processing:
            return self.preview or self.experimental_string_processing
        return self.preview

    def get_cache_key(self) -> str:
        if self.target_versions:
            version_str = ",".join(
                str(version.value)
                for version in sorted(self.target_versions, key=attrgetter("value"))
            )
        else:
            version_str = "-"
        parts = [
            version_str,
            str(self.line_length),
            str(int(self.string_normalization)),
            str(int(self.is_pyi)),
            str(int(self.is_ipynb)),
            str(int(self.magic_trailing_comma)),
            str(int(self.experimental_string_processing)),
            str(int(self.preview)),
        ]
        return ".".join(parts)