Function check_stability_and_equivalence

src/black/__init__.py:1075–1099

Perform stability and equivalence checks. Raise AssertionError if source and destination contents are not equivalent, or if a second pass of the formatter would format the content differently.

(
    src_contents: str,
    dst_contents: str,
    *,
    mode: Mode,
    lines: Collection[tuple[int, int]] = (),
)

def check_stability_and_equivalence(
    src_contents: str,
    dst_contents: str,
    *,
    mode: Mode,
    lines: Collection[tuple[int, int]] = (),
) -> None:
    """Perform stability and equivalence checks.

    Raise AssertionError if source and destination contents are not
    equivalent, or if a second pass of the formatter would format the
    content differently.
    """
    try:
        assert_equivalent(src_contents, dst_contents)
    except SourceASTParseError:
        raise
    except ASTSafetyError:
        if _target_versions_exceed_runtime(mode.target_versions):
            raise ASTSafetyError(
                "failed to verify equivalence of the formatted output:"
                f" {_version_mismatch_message(mode.target_versions)}"
            ) from None
        raise
    assert_stable(src_contents, dst_contents, mode=mode, lines=lines)


def format_file_contents(