Function _make_hash_script

src/attr/_make.py:1611–1680

(
    cls: type, attrs: list[Attribute], frozen: bool, cache_hash: bool
)

def _make_hash_script(
    cls: type, attrs: list[Attribute], frozen: bool, cache_hash: bool
) -> tuple[str, dict]:
    attrs = tuple(
        a for a in attrs if a.hash is True or (a.hash is None and a.eq is True)
    )

    tab = "        "

    type_hash = hash(_generate_unique_filename(cls, "hash"))
    # If eq is custom generated, we need to include the functions in globs
    globs = {}

    hash_def = "def __hash__(self"
    hash_func = "hash(("
    closing_braces = "))"
    if not cache_hash:
        hash_def += "):"
    else:
        hash_def += ", *"

        hash_def += ", _cache_wrapper=__import__('attr._make')._make._CacheHashWrapper):"
        hash_func = "_cache_wrapper(" + hash_func
        closing_braces += ")"

    method_lines = [hash_def]

    def append_hash_computation_lines(prefix, indent):
        """
        Generate the code for actually computing the hash code.
        Below this will either be returned directly or used to compute
        a value which is then cached, depending on the value of cache_hash
        """

        method_lines.extend(
            [
                indent + prefix + hash_func,
                indent + f"        {type_hash},",
            ]
        )

        for a in attrs:
            if a.eq_key:
                cmp_name = f"_{a.name}_key"
                globs[cmp_name] = a.eq_key
                method_lines.append(
                    indent + f"        {cmp_name}(self.{a.name}),"
                )
            else:
                method_lines.append(indent + f"        self.{a.name},")

        method_lines.append(indent + "    " + closing_braces)

    if cache_hash:
        method_lines.append(tab + f"if self.{_HASH_CACHE_FIELD} is None:")
        if frozen:
            append_hash_computation_lines(
                f"object.__setattr__(self, '{_HASH_CACHE_FIELD}', ", tab * 2